GB 700-1988 碳素结构钢

普通碳素结构钢板一、Q234A材质：Q235A标准：GB/T700-1988Q235A概述特性及适用范围：Q235A韧性和塑性较好，有一定的伸长率，具有良好的焊接性能和热加工性。

Q235A一般在热轧状态下使用，用其轧制的型钢、钢筋、钢板、钢管可用于制造各种焊接结构件、桥梁及一般不重要的机器零件，如螺栓、拉杆、铆钉、套环和连杆等。

Q235A图片表示方法：①由Q+数字+质量等级符号+脱氧方法符号组成。

它的钢号冠以“Q”，代表钢材的屈服点，后面的数字表示屈服点数值，单位是MPa例如Q235表示屈服点（σs）为235 MPa的碳素结构钢。

②必要时钢号后面可标出表示质量等级和脱氧方法的符号。

质量等级符号分别为A、B、C、D。

脱氧方法符号：F表示沸腾钢；b表示半镇静钢：Z表示镇静钢；TZ表示特殊镇静钢，镇静钢可不标符号，即Z和TZ都可不标。

例如Q235-AF表示A级沸腾钢。

③专门用途的碳素钢，例如桥用钢。

化学成份碳 C ：0.14～0.22硅 Si：≤0.30锰 Mn：0.30～0.65硫 S ：≤0.050磷 P ：≤0.045铬 Cr：允许残余含量≤0.030镍 Ni：允许残余含量≤0.030铜 Cu：允许残余含量≤0.030注：脱氧方法:F、b、Z力学性能抗拉强度σb (MPa)：375～460屈服强度σs (MPa)：≤16时:≥235; >16～40时:≥225; >40～60时: ≥215; >60～100 时: ≥205; > 100～150 时: ≥195; >150时: ≥185伸长率δ5 (%)：≤16时:≥26;>16～40时:≥25;>40～60时:≥24;>60～100时:≥23;>100～150时:≥22;>150时:≥21试样尺寸：试样厚度(直径)热处理规范及金相组织热处理规范：热轧。

金相组织：铁素体+珠光体。

交货状态:一般以热轧（包括控轧）状态交货。

《碳素结构钢》(GB700—88)标准编制情况综述唐一凡(冶金工业信息标准研究院北京 100730)摘要：重点介绍《碳素结构钢》(GB700-88)修订的必要性，介绍修订后的标准，并进行评述。

(GB700—88)对原普碳钢标准是一次大的改革，采用了国际先进标准和国外技术路线，提锰降碳，减少磷硫含量；分质量等级，按不同质量等级分别规定不同的化学成分和性能指标，提高了基础标准的通用性，适应市场经济发展需要；钢的牌号表示方法改为用屈服点、质量等级、脱氧程度表示，反映了工程结构钢的特点，便于使用选材。

新标准与国际接轨，便于与国际进行技术交流和我国产品进入国际市场。

关键词：碳素结构钢标准修订A COMPILATION SUMMARY OF“CARBON STRUCTURAL STEEL” (GB700—88)Tang yifan(Information Standard Institute of Ministry of Metallurgical Industry Beijing100730)ABSTRACT This paper highlights the necessity of revising“Carbon Structural Steel”(GB700-88)，introduces the revised standards and gives a review．The content of Mn is raised and the contents of C,P and S are decreased using the international advanced standards and the foreign technical line．The different chemical composition and performance index are specified according t0 different quality classifications，which can meet the development market economy．The yield point, quality grade and deoxidation are used to express the brands Of steels，which reflects the features Of engineering structural steels．The new standards are also favorable for technical exchange internationally for China’s products to enter international market．KEY WORDS carbon structural steel standard revision普通碳素钢量大面广，占钢总产量75％左右，广泛用于国民经济各个部门。

材料名称：碳素结构钢牌号：Q195标准：GB/T 700-1988●特性及适用范围：属于乙类碳素钢，伸长率较高，塑性和焊接性能良好。

可用于制造各种焊接结构、桥梁结构和焊接机器结构；也可做铆钉、道钉和一般不重要的机器零件和螺栓、拉杆、连杆、螺母、轴套和销子等。

●化学成份：碳 C ：0.06～0.12硅Si：≤0.30锰Mn：0.25～0.50硫S ：≤0.050磷P：≤0.045铬Cr：允许残余含量≤0.030镍Ni：允许残余含量≤0.030铜Cu：允许残余含量≤0.030注：脱氧方法:F、b、Z●力学性能：抗拉强度σb (MPa)：315～390屈服强度σs (MPa)：≤16时:≥195; ＞16～40时:≥185 (供参考, 不作为供货条件)伸长率δ5 (％)：≤16时:≥33;＞16～40时:≥32试样尺寸：试样厚度(直径)●热处理规范及金相组织：热处理规范：热轧。

金相组织：铁素体+珠光体。

●交货状态：一般以热轧（包括控轧）状态交货。

根据需方要求，经双方协议，也可以正火处理状态交货。

名称＝碳素结构钢0-----------------------------------------------------------0牌号=Q1950材料状态=热扎00σb\Mpa=315～3900σs\Mpa=1950δ5\%=3300试样\毛坯尺寸\mm=≤16mm00化学成分=组成元素比例(%)：碳C:0.06～0.12；锰Mn：0.25～0.50；磷P：≤0.045；硫S：≤0.050；硅Si：≤0.300特性及应用=用途：载荷小的零件、铁丝、垫铁、垫圈开口销、拉杆、冲压件及焊接件。

；脱氧方法：F、b、Z00名称＝碳素结构钢0-----------------------------------------------------------0牌号=Q235-A0材料状态=热扎00σb\Mpa=375～4600σs\Mpa=2350δ5\%=2600试样\毛坯尺寸\mm=≤160化学成分=组成元素比例(%)：碳C:0.14～0.22；锰Mn：0.30～0.65；磷P：≤0.045；硫S：≤0.050；硅Si：≤0.3000特性及应用=用途：金属结构件，心部强度要求不高的的渗碳或氰化零件，拉杆、连杆、吊钩、车钩、螺栓、螺母、套筒、轴及焊接件。

之巴公井开创作H 40National standard of the People's Republic of ChinaGB/T 700-2006WordStr GB/T 700-1988碳素结构钢Carbon structural steels(ISO 630:1995, Structural steels –Plates, wide flats, bars, sections and profiles, NEQ)Issue date: Nov 1, 2006 Implementation date: Feb 1, 2007Issued by: General Administration of Quality Supervision,Inspection and Quarantine of the People’s Republic ofChinaStandardization Administration of the People's Republicof China (SAC)ForewordThis standard is not equivalent to ISO 630:1995Structural Steels in the respect of consistency. The maindifferences between the two standards are as follows:-No grades are specified corresponding to the yieldstrength levels of 185N/mm2 and 355N/mm2;-Grades Q195 and Q215 are specified corresponding to levels 195N/mm2 and 215N/mm2;-The phosphorus contents of class A steels of Q235 and Q275 are decreased by 0.005%;The thickness of Q235 class B steel is divided into two levels according to the deoxidization method and the carbon content is 0.20% in both levels;-Q235 class B steel of which the thickness is smaller than 25mm may not be subject to test with the consent of the buyer if the supplier can ensure that the impact absorbed energy is up to standard;-The yield strength of Q275 steel of which the thickness is bigger than 80mm~100mm is increased by 10N/mm2;-Cold bending test is added;-Detailed batching rules are specified according to the situation of China.This standard WordStrs GB/T 700-1988 Carbon Structural Steels and has the following changes in comparison with GB/T 700-1988:-Semi-killed steel is cancelled in “deoxidizationmethod”;-Grades Q255 and Q275 in GB/T 700-1988 are cancelled;-Grade E275 in ISO 630:1995 is newly added and changed to the new grade Q275;-The lower limits of carbon and manganese contents of each grade are cancelled, and the upper limit of manganese content is increased;-The limit of silicon content of rimmed steel and killed steel is cancelled;-silicon content is changed from 0.30% to 0.35% (except for Q195);-The phosphorus and sulphur contents of grade Q195 are decreased respectively from 0.045% and 0.050% to0.035% and 0.040%;-The regulation for the elongation after fracture of the thickness (or diameter) level of not bigger than 16mm is cancelled;-“The upper limit of the tensile strength of wide strip steel (including sheared steel plate) is not used as a term of delivery” and “Q235 class B steel of which the thickness is smaller than 25mm may not be subject to test with the consent of the buyer if thesupplier can ensure that the impact absorbed energy is up to standard” are added in the footnotes of Table 2; -The regulation for the nitrogen content in the steel is modified;-The regulation for impact test is modified and the figure of the minimum impact absorbed energy of the samples of which the thickness is 5mm-10mm is added;-The basis of batching is changed from “the same furnace and kettle number”to “the same furnace number” and the limitation for the furnace number of mixed batch is cancelled.Annex A of this standard is normative.This standard was proposed by China Iron and Steel Association.This standard is under the jurisdiction of National Technical Committee for Steel Standardization.This standard was drafted by China Metallurgical Information & Standardization Institute, Capital Iron and Steel Company, Handan Iron & Steel Group and Benxi Iron & Steel Group Co., Ltd.The main drafters of this standard are Tang Yifan, Luan Yan, Wang Liping, Sun Ping, Zhang Xianfeng and Dai Qiang.This standard was first issued in January 1965, first revised in October 1979 and revised for the second time in June 1988.Carbon structural steels1 ScopeThis standard specifies the grade, dimension, shape, weight and permissible deviation, technical requirements, test methods, inspection rules, packing, marking and quality certificate of carbon structural steel.This standard is applicable to the structural hot rolled steel sheets, steel strips, sectional steels and bar steels generally used for welding, riveting and bolting engineering in delivery state.The chemical composition specified by this standard is also applicable to steel ingots, continuous casting billets, steel billets and their products.2 Normative referencesThe following normative documents contain provisions which, through reference in this text，constitute provisions of this standard. For dated references, subsequent amendments (not including corrections) to, or revisions of, any of these publications do not apply. However parties to agreements based on this standard areencouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below.For undated references, the latest edition of the normative document referred to applies.GB/T 222-2006Permissible tolerances for chemical composition of steel productsGB/T 223.3 Methods for chemical analysis of iron, steel and alloy--The diantipyryl methane phosphomolybdate gravimetric method for the determination of phosphorus contentGB/T 223.10 Methods for chemical analysis of iron, steel and alloy--The cupferron separation-chrome azurol S photometric method for the determination of aluminum contentGB/T 223.11 Methods for chemical analysis of iron,steel and alloy--The ammonium persulfate oxidation volumetric method for the determination of chromium contentGB/T 223.18 Methods for chemical analysis of iron, steel and alloy--The sodium thiosulfate separation iodimetric method for the determination of copper contentGB/T 223.19 Methods for chemical analysis of iron, steel and alloy--Theneocuproine-chloroformextractionphotometric method for the determination of copper contentGB/T 223.24 Methods for chemical analysis of iron, steel and alloy--The extraction separation-dimethylglyoxime spectrophotometric method for the determination of nickel contentGB/T 223.32 Methods for chemical analysis of iron, steel and alloy--The hypophosphite reduction-iodimetric method for the determination of arsenic contentGB/T 223.37 Methods for chemical analysis of iron, steel and alloy--The indophenol blue photometric method for the determination of nitrogen content after distillation separationGB/T 223.58 Methods for chemical analysis of iron, steel and alloy--The sodium arsenite-sodium nitrite titrimetric method for the determination of manganese contentGB/T 223.59 Methods for chemical analysis of iron,steel and alloy--The reduced molybdoantimonyl phosphoric acid photometric method for the determination of phosphorus contentGB/T 223.60 Methods for chemical analysis of iron, steel and alloy--The perchloric aciddehydration gravimetricmethod for the determination of silicon contentGB/T 223.63 Methods for chemical analysis of iron, steel and alloy--The sodium (potassium) periodate photometric method for the determination of manganese contentGB/T 223.64 Methods for chemical analysis of iron, steel and alloy--The flame atomic absorption spectrometric method for the determination of manganese contentGB/T 223.68 Methods for chemical analysis of iron, steel and alloy--The potassium iodate titration method after combustion in the pipe furnace for the determination of sulfur contentGB/T 223.71 Methods for chemical analysis of iron,steel and alloy--The gravimetric method after combustion in the pipe furnace for the determination of carbon contentGB/T 223.72 Methods for chemical analysis of iron,steel and alloy—The alumina chromatographic separation-barium sulfate gravimetric method for the determination of sulphur contentGB/T 228 Metallic materials-Tensile testing at ambient temperature (GB/T 228-2002, eqv ISO 6892:1998)GB/T 229 Metallic materials - Charpy notch impact test (GB/T 229-1994, eqv ISO 83:1976, eqv ISO 148:1983)GB/T 232 Metallic materials--Bend test (GB/T 232-1999, eqv ISO 7438:1985)GB/T 247 General rule of acceptance, package, mark and certification for steel plates (sheets) and stripsGB/T 2101 General regulation of the checkout, package, mark and quality certificate of profiled barGB/T 2975 Steel and steel products – Location and preparation of test pieces for mechanical testing (GB/T 2975-1998, eqv ISO 377:1997)GB/T 4336 Standard test method for spark discharge atomic emission spectrometric analysis of carbon and low-alloy steel (routine method)GB/T 20066 Steel and iron--Sampling and preparation of samples for the determination of chemical composition (GB/T 20066-2006, ISO 14284:1996, IDT)3 Denotation of the grade and symbols3.1 Denotation of the gradeThe grade of steel is composed of the letter representing yield strength, value of yield strength, symbol of quality grade and symbol of deoxidization method in turn. For example: Q235AF.3.2 SymbolsQ- First letter of Chinese phonetic spelling for the “Qu” word of steel yield strength;A, B, C, D-are respectively quality grade;F- First letter of Chinese phonetic spelling for the “Fei” word of rimmed steel;Z- First letter of Chinese phonetic spelling for the “Zhen” word of killed steel;TZ- First letters of Chinese spelling for the “Tezhen” word of special killed steel.In the denotation of grade components, symbols “Z” and “TZ” can be omitted.4 Dimension, shape, weight and permissible deviationThe dimension, shape, weight and permissible deviation of steel sheets, steel strips, sectional steels and bar steels shall meet the specification of the corresponding standards respectively.5 Technical requirements5.1 Grade and chemical compositionThe grade and chemical composition (smelting analysis) of the steel shall conform to Table 1.Table 15.1.1.1 Class D steels shall have the element with sufficiently refined grains, of which the content shall be indicated in the quality certificate. When aluminum deoxidization is used, the content of acid soluble alumnium in the steel shall not be lower than 0.015% or, alternatively, the total aluminum content shall not be lower than 0.020%.5.1.1.2 The contents of residual elements chromium, nickel and copper in the steel shall not be higher than 0.30% respectively, the nitrogen content shall not be higher than 0.008%. The contents of these elements may not be subject to analysis if they can be guaranteed by the supplier.The nitrogen content is allowed to exceed the value specified in 5.1.1.2. However, with every 0.001%increment of nitrogen content, the maximum phosphorus content shall decrease by 0.005%, the maximum nitrogen content obtained through smelting analysis shall not be higher than 0.012%. If the content of acid soluble aluminum in the steel is not lower than 0.015% or the total aluminum content is not lower than 0.020%, the upper limit of nitrogen content may not be limited. The elements for nitrogen fixation shall be indicated in the quality certificate.5.1.1.2.2 With the consent of the buyer, the copper content of class A steel may not be higher than 0.35%. In this case, the supplier shall analyze the copper content and indicate its content in the quality certificate.5.1.1.3 The arsenic content in the steel shall not be higher than 0.080%. For the steels smelted with arsenic mineral smelting pig iron, the arsenic content shall be specified through negotiation between both parties. If the raw material does not contain arsenic, the analysis of arsenic may not be carried out.If it can be ensured that the mechanical properties of the steel meet the specification of this standard, the carbon, manganese and silicon contents of the Class Asteel of each grade may not be used as terms of delivery. However, their contents shall be indicated in the quality certificate.In case commercial continuous casting billets, steel ingots and steel billets are supplied, the lower limits of carbon and manganese contents of each grade can be specified according to therequirements of the buyer in order to ensure that the performances of rolled steels meet the requirements of this standard.The permissible deviation of the chemical composition of steel product, continuous casting billet and steel billet shall meet the specification of Table 1 of GB/T 222-2006. The nitrogen content is permitted to exceed the specified value. However, it must meet the requirement of clause 5.1.1.2.1. The maximum nitrogen content obtained through product analysis shall not be higher than 0.014%. If the aluminum content in the steel reaches the value specified in and is specified in the quality certificate, the upper limit of nitrogen content may not be limited.The chemical composition deviation of the products and billets of rimmed steel is not guaranteed.Smelting methodThe steel is smelted in oxygen converteror electric furnace. The smelting method is generally selected by the supplier unless the buyer has special requirements and they are noted in the contract.Delivery stateThe steels are generally delivered in hot rolled, controlled rolled or normalized state.Mechanical propertyThe results of tensile and impact tests of the steel shall meet the specification of Table 2. The result of bending test shall meet the specification of Table 3.The thickness (diameter) of the steel products made of Q195 and Q235 class B rimmed steels shall not be bigger than 25mm.When carrying out tensile and cold bending tests, longitudinal samples shall be taken for sectional steels and bar steels, transverse samples shall be taken for steel sheets and steel strips. The elongation after fracture is allowed to be 2% lower (absolute value) than the value specified in Table 2. If the transverse sampling of narrow steel strips is limited by the width, longitudinal samples can be taken.Inspection may not be carried out if the supplier can ensure that the cold bending test meets the specification of Table 3. If Class A steel passes the cold bending test, the upper limit of tensile strength may not be used as a term of delivery.The steel products of which the thickness is not smaller than 12mm or the diameter is not smaller than 16mm shall be subject to impact test. The dimension of sample is 10mm×10mm×55mm. Through negotiation between both parties, the steels of which the thickness is 6mm-12mm or the diameter is 12mm-16mm can be subject to impact test. The dimension of sample is 10mm××55mm or 10mm×5mm×55mm or 10mm×product thickness×55mm. The specified impact absorbed energy is given in Annex A. For example, if the sample of 10mm×5mm×55mm is used, the test result shall not be smaller than 50% of the specified value.The Charpy (V-notch) impact absorbed energy shall be obtained by calculating the arithmetic mean of the single values of three samples in one group. The single value of one sample is allowed to be less than the specified value. However, itshall not be less than 70% of the specified value.If the above condition is not met, carry out the test on another three samples taken from the same product, the mean value of the six samples shall not be less than the specified value. The values of two samples are allowed to be less than the specified value. However, only one sample is allowed to be less than 70% of the specified value.Table 2Table 35.5 Surface qualityThe surface quality of steel products shall respectively meet the specifications of the relevant product standards for steel sheets, steel strips, sectional steels and bar steels.6 Test methodsThe inspection items, sampling number, sampling methods and test methods for each eatch of steel products shall meet the specifications of Table 4.Table 46.2 In tensile and cold bending tests, the longitudinal axis of the samples of steel sheets and steel strips shall be perpendicular to the rolling direction, while the longitudinal axis of the samples of sectional steels, bar steels and narrow steel strips limited by the width shall be parallel to the rolling direction.The longitudinal axis of the impact sample shall be parallel to the rolling direction. The impact sample can reserve one rolled surface.7 Inspection rules7.1 The inspection and acceptance of the steel products shall be carried out by the technical supervision department of the supplier. The buyer has the right to carry out inspection and acceptance on any inspection item specified in this standard or the contract.7.2 The steel products shall be accepted in batches, each batch comprised of the steel products of the same grade, same furnace number, same quality grade, same variety, same dimension and same delivery state. The weight of each batch shall not be greater than 60t.For the steel products rolled with the steels smelted in the steel-making furnaces of which the nominal capacityis small, the Class A or Class B steels of the same furnace number and same grade and manufactured by the same smelting, pouring and deoxidization methods are allowed to form a mixed batch. However, the carbon content difference between the various furnace numbers of each batch shall not be bigger than 0.02%, the manganese content difference shall not be bigger than 0.15%.7.3 If the Charpy (V-notch) impact test result of the steel product does not meet the specification of 5.4.6, the sampling product shall be rejected. Take another two sampling products from the remaining part of this inspection batch and select a new group of three samples from each sampling product. The retest results of these two groups of samples shall be eligible. Otherwise, this batch of product shall not be delivered.7.4 The retest and inspection rules of other inspection items of steel products shall meet the specifications of GB/T 247 and GB/T 2101.8 Packing, marking and quality certificateThe packing, marking and quality certificate of the steel product shall meet the specifications of GB/T 247 and GB/T 2101.Annex A(Normative)Impact absorbed energy of small-sized impact sampleImpact absorbed energy of notched sampleWidth of sample/mm Figure A.1 Minimum impact absorbed energy of the samplesof which the width is 5mm-10mm。

碳素结构钢（GB/T700-1988）
碳素结构钢（GB/1700-1988）
（1）牌号和化学成分见表1。

表1 碳素结构钢的牌号和化学成分
注：F表示沸腾钢，b表示半镇静钢，z表示镇静钢，TZ表示特殊镇静钢。

①Q235A、B级沸腾钢Mn含量上限WMn=0.60%。

②沸腾钢Si含量Wsi不大于0.07%，半镇静钢Si含量Wsi不大于O.17%，镇静钢Si含量WSi限值为0.12%。

（2）力学和工艺性能见表2～表4。

表2 碳素结构钢的屈服点
注：Q195的屈服点仅供参考，不作为交货条件。

表3 碳素结构钢的抗拉强度、伸长率和冲击性能
表4 碳素结构钢的冷弯性能
注：8为试样宽度，a为钢材厚度或直径。

（3）用途见表5。

表5 碳素结构钢的特性和应用
qq空间新浪微博百度搜藏人人网更多。

我国碳素结构钢标准的规定碳素结构钢钢中除含有主要为了脱氧而加入的硅、锰元素外，不含其他有意加入的合金元素。

钢中硫、磷杂质含量较高，一般来说普通质量碳素结构钢的硫的质量分数不大于0.050%、磷的质量分数不大于0.045%；优质碳素结构钢硫和磷的质量分数不大于0.040%。

这类钢通常以热轧状态交货和使用，主要用于工程结构。

根据国家标准GB/T 13304-1991《钢分类》，碳素结构钢属于非合金钢，是非合金钢中的一种。

非合金钢还包括优质碳素结构钢、碳素工具钢、碳素弹簧钢、易切削碳素钢，以及其他一些具有特殊性能和用途的钢。

按化学成分非合金钢各元素规定含量的界限值。

当标准、技术条件或订货单中对钢的熔炼分析化学成分规定最低值或范围时，应以最低值作为规定时进行分类；若规定最高值时，应以最高值的0.7倍作为规定含量进行分类。

根据GB/T 700-1988《碳素结构钢》化学成分的规定，其所包括的各种牌号钢均属于非合金钢。

1。

牌号和化学成分表1 碳素结构钢的牌号和化学成分说明： 1.Q235A，B级沸腾钢锰质量分数上限为0.60%。

2.“F”沸腾钢，“b”半镇静钢、“Z”镇静钢，“TZ”特殊镇静钢。

(2)力学和工艺性能表2 碳素结构钢的屈服点注：Q195的屈服点仅供参考，不作为交货条件表3 碳素结构钢的抗拉强度、伸长率和冲击性能表3-4碳素结构钢的冷弯性能注：8为试样宽度，a为钢材厚度或直径。

(3)用途表4 碳素结构钢的特性和应用碳素结构钢的特性和用途1、牌号Q195，含碳量低，强度不高，塑性、韧性、加工性能和焊接性能好。

用于轧制薄板和盘条。

冷、热轧薄钢板及以其为原料制成的镀锌、镀锡及塑料复合薄钢板大量用于屋面板、装饰板、通用除尘管道、包装容器、铁桶、仪表壳、开关箱、防护罩、火车车厢等。

盘条则多冷拔成低碳钢丝或经镀锌制成镀锌低碳钢丝，用于捆绑、张拉固定或用作钢丝网、铆钉等。

2、牌号Q215，强度稍高于Q195钢，用途与Q195大体相同。

GB 700-88
用途适用于一般结构钢和工程用热轧钢板钢带型钢棒钢产品可供焊接铆接栓接构件用一般在供应状态下使用
Si硅S硫P磷
C碳锰
F b Z
F b Z
F b Z
0.17
3物理性能
屈服强度
s
屈服强度
s
伸长率冲击试验
伸长率5%
直径) (mm)抗拉强度b
为钢材厚度(直径)
4技术要求
4.1当采用5mm*10mm*55mm小尺寸试样做冲击试验时其试验结果应不小于规定值的50%
4.2用沸腾钢制各牌号的B级钢材其厚度直径一般不大于25mm
4.3在保证钢材物理性能符合本标准规定情况下各牌号A级的碳锰含量和各牌号其他等级钢碳锰含量下限可以不作为交货条件但其含量熔炼分析应在质量证明书中注明
4.4在供应商品钢锭包括连铸坯钢坯时供方应保证化学成分熔炼分析符合本表规定但为保证轧制钢材各项性能符合本标准要求各牌号A B级钢
的化学成分可以根据需方要求进行适当调整另定协议。

《碳素结构钢》(GB700—88)标准编制情况综述唐一凡(冶金工业信息标准研究院北京 100730)摘要：重点介绍《碳素结构钢》(GB700-88)修订的必要性，介绍修订后的标准，并进行评述。

(GB700—88)对原普碳钢标准是一次大的改革，采用了国际先进标准和国外技术路线，提锰降碳，减少磷硫含量；分质量等级，按不同质量等级分别规定不同的化学成分和性能指标，提高了基础标准的通用性，适应市场经济发展需要；钢的牌号表示方法改为用屈服点、质量等级、脱氧程度表示，反映了工程结构钢的特点，便于使用选材。

新标准与国际接轨，便于与国际进行技术交流和我国产品进入国际市场。

关键词：碳素结构钢标准修订A COMPILATION SUMMARY OF“CARBON STRUCTURAL STEEL” (GB700—88)Tang yifan(Information Standard Institute of Ministry of Metallurgical Industry Beijing100730)ABSTRACT This paper highlights the necessity of revising“Carbon Structural Steel”(GB700-88)，introduces the revised standards and gives a review．The content of Mn is raised and the contents of C,P and S are decreased using the international advanced standards and the foreign technical line．The different chemical composition and performance index are specified according t0 different quality classifications，which can meet the development market economy．The yield point, quality grade and deoxidation are used to express the brands Of steels，which reflects the features Of engineering structural steels．The new standards are also favorable for technical exchange internationally for China’s products to enter international market．KEY WORDS carbon structural steel standard revision普通碳素钢量大面广，占钢总产量75％左右，广泛用于国民经济各个部门。

之南宫帮珍创作H 40National standard of the People's Republic of ChinaGB/T 700-2006WordStr GB/T 700-1988碳素结构钢Carbon structural steels(ISO 630:1995, Structural steels –Plates, wide flats, bars, sections and profiles, NEQ)Issue date: Nov 1, 2006 Implementation date: Feb 1, 2007Issued by: General Administration of Quality Supervision,Inspection and Quarantine of the People’s Republic ofChinaStandardization Administration of the People's Republicof China (SAC)ForewordThis standard is not equivalent to ISO 630:1995Structural Steels in the respect of consistency. The maindifferences between the two standards are as follows:-No grades are specified corresponding to the yield strength levels of 185N/mm2 and 355N/mm2;-Grades Q195 and Q215 are specified corresponding to levels 195N/mm2 and 215N/mm2;-The phosphorus contents of class A steels of Q235 and Q275 are decreased by 0.005%;The thickness of Q235 class B steel is divided into two levels according to the deoxidization method and the carbon content is 0.20% in both levels;-Q235 class B steel of which the thickness is smaller than 25mm may not be subject to test with the consent of the buyer if the supplier can ensure that the impact absorbed energy is up to standard;-The yield strength of Q275 steel of which the thickness is bigger than 80mm~100mm is increased by 10N/mm2;-Cold bending test is added;-Detailed batching rules are specified according to the situation of China.This standard WordStrs GB/T 700-1988 Carbon Structural Steels and has the following changes in comparison with GB/T 700-1988:-Semi-killed steel is cancelled in “deoxidization method”;-Grades Q255 and Q275 in GB/T 700-1988 are cancelled;-Grade E275 in ISO 630:1995 is newly added and changed to the new grade Q275;-The lower limits of carbon and manganese contents of each grade are cancelled, and the upper limit of manganese content is increased;-The limit of silicon content of rimmed steel and killed steel is cancelled;-silicon content is changed from 0.30% to 0.35% (except for Q195);-The phosphorus and sulphur contents of grade Q195 are decreased respectively from 0.045% and 0.050% to0.035% and 0.040%;-The regulation for the elongation after fracture of the thickness (or diameter) level of not bigger than 16mm is cancelled;-“The upper limit of the tensile strength of wide strip steel (including sheared steel plate) is not used as a term of delivery” and “Q235 class B steel of which the thickness is smaller than 25mm may not besubject to test with the consent of the buyer if the supplier can ensure that the impact absorbed energy is up to standard” are added in the footnotes of Table 2; -The regulation for the nitrogen content in the steel is modified;-The regulation for impact test is modified and the figure of the minimum impact absorbed energy of the samples of which the thickness is 5mm-10mm is added;-The basis of batching is changed from “the same furnace and kettle number”to “the same furnace number” and the limitation for the furnace number of mixed batch is cancelled.Annex A of this standard is normative.This standard was proposed by China Iron and Steel Association.This standard is under the jurisdiction of National Technical Committee for Steel Standardization.This standard was drafted by China Metallurgical Information & Standardization Institute, Capital Iron and Steel Company, Handan Iron & Steel Group and Benxi Iron & Steel Group Co., Ltd.The main drafters of this standard are Tang Yifan, LuanYan, Wang Liping, Sun Ping, Zhang Xianfeng and Dai Qiang. This standard was first issued in January 1965, first revised in October 1979 and revised for the second time in June 1988.Carbon structural steels1 ScopeThis standard specifies the grade, dimension, shape, weight and permissible deviation, technical requirements, test methods, inspection rules, packing, marking and quality certificate of carbon structural steel.This standard is applicable to the structural hot rolled steel sheets, steel strips, sectional steels and bar steels generally used for welding, riveting and bolting engineering in delivery state.The chemical composition specified by this standard is also applicable to steel ingots, continuous casting billets, steel billets and their products.2 Normative referencesThe following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (not including corrections) to, or revisions of, any of these publications do not apply.However parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below.For undated references, the latest edition of the normative document referred to applies.GB/T 222-2006Permissible tolerances for chemical composition of steel productsGB/T 223.3 Methods for chemical analysis of iron, steel and alloy--The diantipyryl methane phosphomolybdate gravimetric method for the determination of phosphorus contentGB/T 223.10 Methods for chemical analysis of iron, steel and alloy--The cupferron separation-chrome azurol S photometric method for the determination of aluminum contentGB/T 223.11 Methods for chemical analysis of iron,steel and alloy--The ammonium persulfate oxidation volumetric method for the determination of chromium contentGB/T 223.18 Methods for chemical analysis of iron, steel and alloy--The sodium thiosulfate separation iodimetric method for the determination of copper contentGB/T 223.19 Methods for chemical analysis of iron, steeland alloy--Theneocuproine-chloroformextraction photometric method for the determination of copper contentGB/T 223.24 Methods for chemical analysis of iron, steel and alloy--The extraction separation-dimethylglyoxime spectrophotometric method for the determination of nickel contentGB/T 223.32 Methods for chemical analysis of iron, steel and alloy--The hypophosphite reduction-iodimetric method for the determination of arsenic contentGB/T 223.37 Methods for chemical analysis of iron, steel and alloy--The indophenol blue photometric method for the determination of nitrogen content after distillation separationGB/T 223.58 Methods for chemical analysis of iron, steel and alloy--The sodium arsenite-sodium nitrite titrimetric method for the determination of manganese contentGB/T 223.59 Methods for chemical analysis of iron,steel and alloy--The reduced molybdoantimonyl phosphoric acid photometric method for the determination of phosphorus contentGB/T 223.60 Methods for chemical analysis of iron, steeland alloy--The perchloric aciddehydration gravimetric method for the determination of silicon contentGB/T 223.63 Methods for chemical analysis of iron, steel and alloy--The sodium (potassium) periodate photometric method for the determination of manganese contentGB/T 223.64 Methods for chemical analysis of iron, steel and alloy--The flame atomic absorption spectrometric method for the determination of manganese contentGB/T 223.68 Methods for chemical analysis of iron, steel and alloy--The potassium iodate titration method after combustion in the pipe furnace for the determination of sulfur contentGB/T 223.71 Methods for chemical analysis of iron,steel and alloy--The gravimetric method after combustion in the pipe furnace for the determination of carbon contentGB/T 223.72 Methods for chemical analysis of iron,steel and alloy—The alumina chromatographic separation-barium sulfate gravimetric method for the determination of sulphur contentGB/T 228 Metallic materials-Tensile testing at ambient temperature (GB/T 228-2002, eqv ISO 6892:1998)GB/T 229 Metallic materials - Charpy notch impact test(GB/T 229-1994, eqv ISO 83:1976, eqv ISO 148:1983)GB/T 232 Metallic materials--Bend test (GB/T 232-1999, eqv ISO 7438:1985)GB/T 247 General rule of acceptance, package, mark and certification for steel plates (sheets) and stripsGB/T 2101 General regulation of the checkout, package, mark and quality certificate of profiled barGB/T 2975 Steel and steel products – Location and preparation of test pieces for mechanical testing (GB/T 2975-1998, eqv ISO 377:1997)GB/T 4336 Standard test method for spark discharge atomic emission spectrometric analysis of carbon and low-alloy steel (routine method)GB/T 20066 Steel and iron--Sampling and preparation of samples for the determination of chemical composition (GB/T 20066-2006, ISO 14284:1996, IDT)3 Denotation of the grade and symbols3.1 Denotation of the gradeThe grade of steel is composed of the letter representing yield strength, value of yield strength, symbol of quality grade and symbol of deoxidization method in turn. For example: Q235AF.3.2 SymbolsQ- First letter of Chinese phonetic spelling for the “Qu” word of steel yield strength;A, B, C, D-are respectively quality grade;F- First letter of Chinese phonetic spelling for the “Fei” word of rimmed steel;Z- First letter of Chinese phonetic spelling for the “Zhen” word of killed steel;TZ- First letters of Chinese spelling for the “Tezhen” word of special killed steel.In the denotation of grade components, symbols “Z” and “TZ” can be omitted.4 Dimension, shape, weight and permissible deviationThe dimension, shape, weight and permissible deviation of steel sheets, steel strips, sectional steels and bar steels shall meet the specification of the corresponding standards respectively.5 Technical requirements5.1 Grade and chemical compositionThe grade and chemical composition (smelting analysis) of the steel shall conform to Table 1.Table 15.1.1.1 Class D steels shall have the element with sufficiently refined grains, of which the content shall be indicated in the quality certificate. When aluminum deoxidization is used, the content of acid soluble alumnium in the steel shall not be lower than 0.015% or, alternatively, the total aluminum content shall not be lower than 0.020%.5.1.1.2 The contents of residual elements chromium, nickel and copper in the steel shall not be higher than 0.30% respectively, the nitrogen content shall not be higher than 0.008%. The contents of these elements may not be subject to analysis if they can be guaranteed by the supplier.The nitrogen content is allowed to exceed the valuespecified in 5.1.1.2. However, with every 0.001% increment of nitrogen content, the maximum phosphorus content shall decrease by 0.005%, the maximum nitrogen content obtained through smelting analysis shall not be higher than 0.012%. If the content of acid soluble aluminum in the steel is not lower than 0.015% or the total aluminum content is not lower than 0.020%, the upper limit of nitrogen content may not be limited. The elements for nitrogen fixation shall be indicated in the quality certificate.5.1.1.2.2 With the consent of the buyer, the copper content of class A steel may not be higher than 0.35%. In this case, the supplier shall analyze the copper content and indicate its content in the quality certificate.5.1.1.3 The arsenic content in the steel shall not be higher than 0.080%. For the steels smelted with arsenic mineral smelting pig iron, the arsenic content shall be specified through negotiation between both parties. If the raw material does not contain arsenic, the analysis of arsenic may not be carried out.If it can be ensured that the mechanical properties of the steel meet the specification of this standard, thecarbon, manganese and silicon contents of the Class A steel of each grade may not be used as terms of delivery. However, their contents shall be indicated in the quality certificate.In case commercial continuous casting billets, steel ingots and steel billets are supplied, the lower limits of carbon and manganese contents of each grade can be specified according to therequirements of the buyer in order to ensure that the performances of rolled steels meet the requirements of this standard.The permissible deviation of the chemical composition of steel product, continuous casting billet and steel billet shall meet the specification of Table 1 of GB/T 222-2006. The nitrogen content is permitted to exceed the specified value. However, it must meet the requirement of clause 5.1.1.2.1. The maximum nitrogen content obtained through product analysis shall not be higher than 0.014%. If the aluminum content in the steel reaches the value specified in and is specified in the quality certificate, the upper limit of nitrogen content may not be limited.The chemical composition deviation of the products and billets of rimmed steel is not guaranteed.Smelting methodThe steel is smelted in oxygen converteror electric furnace. The smelting method is generally selected by the supplier unless the buyer has special requirements and they are noted in the contract.Delivery stateThe steels are generally delivered in hot rolled, controlled rolled or normalized state.Mechanical propertyThe results of tensile and impact tests of the steel shall meet the specification of Table 2. The result of bending test shall meet the specification of Table 3.The thickness (diameter) of the steel products made of Q195 and Q235 class B rimmed steels shall not be bigger than 25mm.When carrying out tensile and cold bending tests, longitudinal samples shall be taken for sectional steels and bar steels, transverse samples shall be taken for steel sheets and steel strips. The elongation after fracture is allowed to be 2% lower (absolute value) than the value specified in Table 2. If the transverse sampling of narrow steel strips is limited by the width,longitudinal samples can be taken.Inspection may not be carried out if the supplier can ensure that the cold bending test meets the specification of Table 3. If Class A steel passes the cold bending test, the upper limit of tensile strength may not be used as a term of delivery.The steel products of which the thickness is not smaller than 12mm or the diameter is not smaller than 16mm shall be subject to impact test. The dimension of sample is 10mm×10mm×55mm. Through negotiation between both parties, the steels of which the thickness is 6mm-12mm or the diameter is 12mm-16mm can be subject to impact test. The dimension of sample is 10mm××55mm or 10mm×5mm×55mm or 10mm×product thickness×55mm. The specified impact absorbed energy is given in Annex A. For example, if the sample of 10mm×5mm×55mm is used, the test result shall not be smaller than 50% of the specified value.The Charpy (V-notch) impact absorbed energy shall be obtained by calculating the arithmetic mean of the single values of three samples in one group. The single value of one sample is allowed to be less than the specified value. However, itshall not be less than 70% of the specifiedvalue.If the above condition is not met, carry out the test on another three samples taken from the same product, the mean value of the six samples shall not be less than the specified value. The values of two samples are allowed to be less than the specified value. However, only one sample is allowed to be less than 70% of the specified value.Table 2Table 35.5 Surface qualityThe surface quality of steel products shall respectively meet the specifications of the relevant product standards for steel sheets, steel strips, sectional steels and bar steels.6 Test methodsThe inspection items, sampling number, sampling methods and test methods for each eatch of steel products shall meet the specifications of Table 4.Table 46.2 In tensile and cold bending tests, the longitudinal axis of the samples of steel sheets and steel strips shall be perpendicular to the rolling direction, while the longitudinal axis of the samples of sectional steels, bar steels and narrow steel strips limited by the width shall be parallel to the rolling direction.The longitudinal axis of the impact sample shall be parallel to the rolling direction. The impact sample can reserve one rolled surface.7 Inspection rules7.1 The inspection and acceptance of the steel products shall be carried out by the technical supervision department of the supplier. The buyer has the right to carry out inspection and acceptance on any inspection item specified in this standard or the contract.7.2 The steel products shall be accepted in batches, each batch comprised of the steel products of the same grade, same furnace number, same quality grade, same variety, same dimension and same delivery state. The weight of each batch shall not be greater than 60t.For the steel products rolled with the steels smelted in the steel-making furnaces of which the nominal capacityis small, the Class A or Class B steels of the same furnace number and same grade and manufactured by the same smelting, pouring and deoxidization methods are allowed to form a mixed batch. However, the carbon content difference between the various furnace numbers of each batch shall not be bigger than 0.02%, the manganese content difference shall not be bigger than 0.15%.7.3 If the Charpy (V-notch) impact test result of the steel product does not meet the specification of 5.4.6, the sampling product shall be rejected. Take another two sampling products from the remaining part of this inspection batch and select a new group of three samples from each sampling product. The retest results of these two groups of samples shall be eligible. Otherwise, this batch of product shall not be delivered.7.4 The retest and inspection rules of other inspection items of steel products shall meet the specifications of GB/T 247 and GB/T 2101.8 Packing, marking and quality certificateThe packing, marking and quality certificate of the steel product shall meet the specifications of GB/T 247 and GB/T 2101.Annex A(Normative)Impact absorbed energy of small-sized impact sampleImpact absorbed energy of notched sampleWidth of sample/mm Figure A.1 Minimum impact absorbed energy of the samples创作时间：二零二一年六月三十日of which the width is 5mm-10mm创作时间：二零二一年六月三十日。

GB 700-88
用途适用于一般结构钢和工程用热轧钢板钢带型钢棒钢产品可供焊接铆接栓接构件用一般在供应状态下使用
Si硅S硫P磷
C碳锰
F b Z
F b Z
F b Z
0.17
物理性能
屈服强度
s
屈服强度
s
伸长率冲击试验
伸长率5%
直径) (mm)抗拉强度b
为钢材厚度(直径)
技术要求
4.1当采用5mm*10mm*55mm小尺寸试样做冲击试验时其试验结果应不小于规定值的50%
4.2用沸腾钢制各牌号的B级钢材其厚度直径一般不大于25mm
4.3在保证钢材物理性能符合本标准规定情况下各牌号A级的碳锰含量和各牌号其他等级钢碳锰含量下限可以不作为交货条件但其含量熔炼分析应在质量证明书中注明
4.4在供应商品钢锭包括连铸坯钢坯时供方应保证化学成分熔炼分析符合本表规定但为保证轧制钢材各项性能符合本标准要求各牌号A B级钢
的化学成分可以根据需方要求进行适当调整另定协议。

ICS 77.140.45H 40National standard of the People's Republic of ChinaGB/T 700-2006Replace GB/T 700-1988碳素结构钢Carbon structural steels(ISO 630:1995, Structural steels –Plates, wide flats, bars, sections and profiles, NEQ)Issue date: Nov 1, 2006 Implementation date: Feb 1, 2007Issued by: General Administration of Quality Supervision, Inspection and Quarantine of the People’sRepublic of ChinaStandardization Administration of the People's Republicof China (SAC)ForewordThis standard is not equivalent to ISO 630:1995Structural Steels in the respect of consistency. Themain differences between the two standards are as follows:-No grades are specified corresponding to the yield strength levels of 185N/mm2 and 355N/mm2;-Grades Q195 and Q215 are specified corresponding to levels 195N/mm2 and 215N/mm2;-The phosphorus contents of class A steels of Q235 and Q275 are decreased by 0.005%;The thickness of Q235 class B steel is divided into two levels according to the deoxidization method and the carbon content is 0.20% in both levels;-Q235 class B steel of which the thickness is smaller than 25mm may not be subject to test with the consent of the buyer if the supplier can ensure that the impact absorbed energy is up to standard;-The yield strength of Q275 steel of which the thickness is bigger than 80mm~100mm is increased by 10N/mm2;-Cold bending test is added;-Detailed batching rules are specified according to the situation of China.This standard replaces GB/T 700-1988 Carbon StructuralSteels and has the following changes in comparison with GB/T 700-1988:-Semi-killed steel is cancelled in “deoxidization method”;-Grades Q255 and Q275 in GB/T 700-1988 are cancelled; -Grade E275 in ISO 630:1995 is newly added and changed to the new grade Q275;-The lower limits of carbon and manganese contents of each grade are cancelled, and the upper limit of manganese content is increased;-The limit of silicon content of rimmed steel and killed steel is cancelled;-silicon content is changed from 0.30% to 0.35% (except for Q195);-The phosphorus and sulphur contents of grade Q195 are decreased respectively from 0.045% and 0.050% to0.035% and 0.040%;-The regulation for the elongation after fracture of the thickness (or diameter) level of not bigger than 16mm is cancelled;-“The upper limit of the tensile strength of wide strip steel (including sheared steel plate) is notused as a term of delivery”and “Q235 class B steel of which the thickness is smaller than 25mm may not be subject to test with the consent of the buyer if the supplier can ensure that the impact absorbed energy is up to standard” are added in the footnotes of Table 2;-The regulation for the nitrogen content in the steel is modified;-The regulation for impact test is modified and the figure of the minimum impact absorbed energy of the samples of which the thickness is 5mm-10mm is added; -The basis of batching is changed from “the same furnace and kettle number”to “the same furnace number”and the limitation for the furnace number of mixed batch is cancelled.Annex A of this standard is normative.This standard was proposed by China Iron and Steel Association.This standard is under the jurisdiction of National Technical Committee for Steel Standardization.This standard was drafted by China Metallurgical Information & Standardization Institute, Capital Ironand Steel Company, Handan Iron & Steel Group and Benxi Iron & Steel Group Co., Ltd.The main drafters of this standard are Tang Yifan, Luan Yan, Wang Liping, Sun Ping, Zhang Xianfeng and Dai Qiang.This standard was first issued in January 1965, first revised in October 1979 and revised for the second time in June 1988.Carbon structural steels1 ScopeThis standard specifies the grade, dimension, shape, weight and permissible deviation, technical requirements, test methods, inspection rules, packing, marking and quality certificate of carbon structural steel.This standard is applicable to the structural hot rolled steel sheets, steel strips, sectional steels and bar steels generally used for welding, riveting and bolting engineering in delivery state.The chemical composition specified by this standard is also applicable to steel ingots, continuous casting billets, steel billets and their products.2 Normative referencesThe following normative documents contain provisions which, through reference in this text，constitute provisions of this standard. For dated references, subsequent amendments (not including corrections) to, or revisions of, any of these publications do not apply. However parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below.For undated references, the latest edition of the normative document referred to applies.GB/T 222-2006Permissible tolerances for chemical composition of steel productsGB/T 223.3 Methods for chemical analysis of iron, steel and alloy--The diantipyryl methane phosphomolybdate gravimetric method for the determination of phosphorus contentGB/T 223.10 Methods for chemical analysis of iron, steel and alloy--The cupferron separation-chrome azurol S photometric method for the determination of aluminum contentGB/T 223.11 Methods for chemical analysis of iron,steel and alloy--The ammonium persulfate oxidation volumetric method for the determination of chromium contentGB/T 223.18 Methods for chemical analysis of iron, steel and alloy--The sodium thiosulfate separation iodimetric method for the determination of copper contentGB/T 223.19 Methods for chemical analysis of iron,steel and alloy--Theneocuproine-chloroformextraction photometric method for the determination of copper contentGB/T 223.24 Methods for chemical analysis of iron,steel and alloy--The extraction separation-dimethylglyoxime spectrophotometric method for the determination of nickel contentGB/T 223.32 Methods for chemical analysis of iron,steel and alloy--The hypophosphite reduction-iodimetric method for the determination of arsenic contentGB/T 223.37 Methods for chemical analysis of iron,steel and alloy--The indophenol blue photometric method for the determination of nitrogen content after distillation separationGB/T 223.58 Methods for chemical analysis of iron,steel and alloy--The sodium arsenite-sodium nitrite titrimetric method for the determination of manganese contentGB/T 223.59 Methods for chemical analysis of iron,steel and alloy--The reduced molybdoantimonyl phosphoric acid photometric method for the determination of phosphorus contentGB/T 223.60 Methods for chemical analysis of iron,steel and alloy--The perchloric aciddehydration gravimetric method for the determination of silicon contentGB/T 223.63 Methods for chemical analysis of iron,steel and alloy--The sodium (potassium) periodate photometric method for the determination of manganese contentGB/T 223.64 Methods for chemical analysis of iron,steel and alloy--The flame atomic absorption spectrometric method for the determination of manganese contentGB/T 223.68 Methods for chemical analysis of iron,steel and alloy--The potassium iodate titration methodafter combustion in the pipe furnace for the determination of sulfur contentGB/T 223.71 Methods for chemical analysis of iron,steel and alloy--The gravimetric method after combustion in the pipe furnace for the determination of carbon contentGB/T 223.72 Methods for chemical analysis of iron,steel and alloy—The alumina chromatographic separation-barium sulfate gravimetric method for the determination of sulphur contentGB/T 228 Metallic materials-Tensile testing at ambient temperature (GB/T 228-2002, eqv ISO 6892:1998)GB/T 229 Metallic materials - Charpy notch impact test (GB/T 229-1994, eqv ISO 83:1976, eqv ISO 148:1983)GB/T 232 Metallic materials--Bend test (GB/T 232-1999, eqv ISO 7438:1985)GB/T 247 General rule of acceptance, package, mark and certification for steel plates (sheets) and stripsGB/T 2101 General regulation of the checkout, package, mark and quality certificate of profiled barGB/T 2975 Steel and steel products – Location and preparation of test pieces for mechanical testing (GB/T2975-1998, eqv ISO 377:1997)GB/T 4336 Standard test method for spark discharge atomic emission spectrometric analysis of carbon and low-alloy steel (routine method)GB/T 20066 Steel and iron--Sampling and preparation of samples for the determination of chemical composition (GB/T 20066-2006, ISO 14284:1996, IDT)3 Denotation of the grade and symbols3.1 Denotation of the gradeThe grade of steel is composed of the letter representing yield strength, value of yield strength, symbol of quality grade and symbol of deoxidization method in turn. For example: Q235AF.3.2 SymbolsQ- First letter of Chinese phonetic spelling for the “Qu” word of ste el yield strength;A, B, C, D-are respectively quality grade;F- First letter of Chinese phonetic spelling for the “Fei” word of rimmed steel;Z- First letter of Chinese phonetic spelling for the “Zhen” word of killed steel;TZ- First letters of Chinese spelling for the“Tezhen” word of special killed steel.In the denotation of grade components, symbols “Z” and “TZ” can be omitted.4 Dimension, shape, weight and permissible deviation The dimension, shape, weight and permissible deviation of steel sheets, steel strips, sectional steels and bar steels shall meet the specification of the corresponding standards respectively.5 Technical requirements5.1 Grade and chemical composition5.1.1The grade and chemical composition (smelting analysis) of the steel shall conform to Table 1.Table 15.1.1.1 Class D steels shall have the element withsufficiently refined grains, of which the content shall be indicated in the quality certificate. When aluminum deoxidization is used, the content of acid soluble alumnium in the steel shall not be lower than 0.015% or, alternatively, the total aluminum content shall not be lower than 0.020%.5.1.1.2 The contents of residual elements chromium, nickel and copper in the steel shall not be higher than 0.30% respectively, the nitrogen content shall not be higher than 0.008%. The contents of these elements may not be subject to analysis if they can be guaranteed by the supplier.5.1.1.2.1 The nitrogen content is allowed to exceed the value specified in 5.1.1.2. However, with every 0.001% increment of nitrogen content, the maximum phosphorus content shall decrease by 0.005%, the maximum nitrogen content obtained through smelting analysis shall not be higher than 0.012%. If the content of acid soluble aluminum in the steel is not lower than 0.015% or the total aluminum content is not lower than 0.020%, the upper limit of nitrogen content may not be limited. The elements for nitrogen fixation shall be indicated inthe quality certificate.5.1.1.2.2 With the consent of the buyer, the copper content of class A steel may not be higher than 0.35%. In this case, the supplier shall analyze the copper content and indicate its content in the quality certificate.5.1.1.3 The arsenic content in the steel shall not be higher than 0.080%. For the steels smelted with arsenic mineral smelting pig iron, the arsenic content shall be specified through negotiation between both parties. If the raw material does not contain arsenic, the analysis of arsenic may not be carried out.5.1.1.4If it can be ensured that the mechanical properties of the steel meet the specification of this standard, the carbon, manganese and silicon contents of the Class A steel of each grade may not be used as terms of delivery. However, their contents shall be indicated in the quality certificate.5.1.1.5 In case commercial continuous casting billets, steel ingots and steel billets are supplied, the lower limits of carbon and manganese contents of each grade can be specified according to therequirements of thebuyer in order to ensure that the performances of rolled steels meet the requirements of this standard. 5.1.2The permissible deviation of the chemical composition of steel product, continuous casting billet and steel billet shall meet the specification of Table 1 of GB/T 222-2006.The nitrogen content is permitted to exceed the specified value. However, it must meet the requirement of clause 5.1.1.2.1. The maximum nitrogen content obtained through product analysis shall not be higher than 0.014%. If the aluminum content in the steel reaches the value specified in 5.1.1.2.1and is specified in the quality certificate, the upper limit of nitrogen content may not be limited.The chemical composition deviation of the products and billets of rimmed steel is not guaranteed.5.2 Smelting methodThe steel is smelted in oxygen converteror electric furnace. The smelting method is generally selected by the supplier unless the buyer has special requirements and they are noted in the contract.5.3 Delivery stateThe steels are generally delivered in hot rolled, controlled rolled or normalized state.5.4 Mechanical property5.4.1The results of tensile and impact tests of the steel shall meet the specification of Table 2. The result of bending test shall meet the specification of Table 3.5.4.2The thickness (diameter) of the steel products made of Q195 and Q235 class B rimmed steels shall not be bigger than 25mm.5.4.3 When carrying out tensile and cold bending tests, longitudinal samples shall be taken for sectional steels and bar steels, transverse samples shall be taken for steel sheets and steel strips. The elongation after fracture is allowed to be 2% lower (absolute value) than the value specified in Table 2. If the transverse sampling of narrow steel strips is limited by the width, longitudinal samples can be taken.5.4.4 Inspection may not be carried out if the supplier can ensure that the cold bending test meets the specification of Table 3. If Class A steel passes the cold bending test, the upper limit of tensile strengthmay not be used as a term of delivery.5.4.5 The steel products of which the thickness is not smaller than 12mm or the diameter is not smaller than 16mm shall be subject to impact test. The dimension of sample is 10mm×10mm×55mm. Through negotiation between both parties, the steels of which the thickness is 6mm-12mm or the diameter is 12mm-16mm can be subject to impact test. The dimension of sample is 10mm×7.5mm×55mm or 10mm×5mm×55mm or 10mm×product thickness×55mm. The specified impact absorbed energy is given in Annex A. For example, if the sample of 10mm×5mm×55mm is used, the test result shall not be smaller than 50% of the specified value.5.4.6The Charpy (V-notch) impact absorbed energy shall be obtained by calculating the arithmetic mean of the single values of three samples in one group. The single value of one sample is allowed to be less than the specified value. However, itshall not be less than 70% of the specified value.If the above condition is not met, carry out the test on another three samples taken from the same product, the mean value of the six samples shall not be lessthan the specified value. The values of two samples are allowed to be less than the specified value. However, only one sample is allowed to be less than 70% of the specified value.Table 2Table 35.5 Surface qualityThe surface quality of steel products shall respectively meet the specifications of the relevant product standards for steel sheets, steel strips, sectional steels and bar steels.6 Test methods6.1The inspection items, sampling number, sampling methods and test methods for each eatch of steel products shall meet the specifications of Table 4.Table 46.2 In tensile and cold bending tests, the longitudinal axis of the samples of steel sheets and steel strips shall be perpendicular to the rolling direction, while the longitudinal axis of the samples of sectional steels, bar steels and narrow steel strips limited bythe width shall be parallel to the rolling direction. 6.3 The longitudinal axis of the impact sample shall be parallel to the rolling direction. The impact sample can reserve one rolled surface.7 Inspection rules7.1 The inspection and acceptance of the steel products shall be carried out by the technical supervision department of the supplier. The buyer has the right to carry out inspection and acceptance on any inspection item specified in this standard or the contract.7.2 The steel products shall be accepted in batches, each batch comprised of the steel products of the same grade, same furnace number, same quality grade, same variety, same dimension and same delivery state. The weight of each batch shall not be greater than 60t.For the steel products rolled with the steels smelted in the steel-making furnaces of which the nominal capacity is small, the Class A or Class B steels of the same furnace number and same grade and manufactured by the same smelting, pouring and deoxidization methods are allowed to form a mixed batch. However, the carbon content difference between the various furnace numbersof each batch shall not be bigger than 0.02%, the manganese content difference shall not be bigger than 0.15%.7.3 If the Charpy (V-notch) impact test result of the steel product does not meet the specification of 5.4.6, the sampling product shall be rejected. Take another two sampling products from the remaining part of this inspection batch and select a new group of three samples from each sampling product. The retest results of these two groups of samples shall be eligible. Otherwise, this batch of product shall not be delivered.7.4 The retest and inspection rules of other inspection items of steel products shall meet the specifications of GB/T 247 and GB/T 2101.8 Packing, marking and quality certificateThe packing, marking and quality certificate of the steel product shall meet the specifications of GB/T 247 and GB/T 2101.Annex A(Normative)Impact absorbed energy of small-sized impact sample欧阳文创编欧阳文创编Width of sample/mmFigure A.1 Minimum impact absorbed energy of the samples of which the width is 5mm-10mmImpact absorbed energy of notched sample。

中华人民共和国国家标准碳素结构钢UDC669.14.018.29GB700-88代替GB700-79本标准参照采用IS0630《结构钢》。

1 主题内容与适用范围. 本标准规定碳素结构钢的技术条件。

. 本标准适用于一般结构钢和工程用热轧钢板,钢带、型钢、棒钢。

该产品可供焊接、绑接、栓接构件用,一般在供应状态下使用。

. 本标准规定的化学成分适用于钢锭〈包括连铸坯〉、钢坯及其制品。

2 引用标准. GB 222 钢的化学分析用试样取样法及成品化学成分允许偏差. GB 223 钢铁及合金化学分析方法. GB 228 金属拉伸试验方法. GB 232 金属弯曲试验方法. GB 247 钢板和钢带验收、包装、标志及质量证明书的一般规定. GB 2101 型钢验收、包装、标志及质量证明书的一般规定. GB 2106 金属夏比〈V型缺口〉冲击试验方法. GB 2975 钢材力学及工艺性能试验取样规定-. GB 4159 金属低温夏比冲击试验方法. GB 6397 金属拉伸试验试样3 牌号表示方法、代号和符号3.1 牌号表示方法. 钢的牌号由代表屈服点的字母、屈服点数值、质量等级符号、脱氧方法符号等四个部分按顺序组成。

例如：Q235-A·F3.2 符号. Q--钢材屈服点"屈"字汉语拼音首位字母；. A、B、C、D一一分别为质量等级;. F--沸腾钢"沸"字汉语拼音首位字母；. B--半镇静钢"半"字汉语拼音首位字母；. Z--镇静钢"镇"字汉语拼音首位字母；. TZ--特殊镇静钢"特镇"两字汉语拼音首位字母。

. 在牌号组成表示方法中,"Z"与"TZ"符号予以省略。

4 尺寸、外形、重量及允许偏差. 钢材的尺寸、外形、重量及允许偏差应符合相应标准的规定。

5 技术要求5.1 牌号和化学成分. 钢的牌号和化学成分(熔炼分析)应符合表1规定。

碳素结构钢的定义与分类碳素结构钢钢中除含有主要为了脱氧而加入的硅、锰元素外，不含其他有意加入的合金元素。

钢中硫、磷杂质含量较高，一般来说普通质量碳素结构钢的硫的质量分数不大于0.050%、磷的质量分数不大于0.045%；优质碳素结构钢硫和磷的质量分数不大于0.040%。

这类钢通常以热轧状态交货和使用，主要用于工程结构。

一、我国标准的规定根据国家标准GB/T 13304-1991《钢分类》，碳素结构钢属于非合金钢，是非合金钢中的一种。

非合金钢还包括优质碳素结构钢、碳素工具钢、碳素弹簧钢、易切削碳素钢，以及其他一些具有特殊性能和用途的钢。

（一）按化学成分非合金钢各元素规定含量的界限值如表1-1-1所示。

对钢规定的任一元素的规定含量符合表中所列相应元素的界限范围时，这些钢不非合金钢。

表1－1－1是指不规定生产过程中需要特别控制质量要求的，并应同时符合下列4种条件的钢。

（1）钢为非合金化的（符合对非合金钢的合金元素规定含量界限值的规定）；（2）不规定热处理（退火、正火、消除应力及软化处理不作为热处理）；（3）如产品标准或技术条件中有规定，其特性值应符合下列条件：碳的质量分数最高值≥0.10%；硫或磷的质量分数最高值≥0.045%；氮的质量分数最高值≥0.007%；抗拉强度最低值≤690MPa；屈服点或屈服强度最低值≤360MPa；伸长率最低值（Lo=5.65 Fo ）≤33%；弯心直径最低值≥0.5*试件厚度；冲击功最低值（20℃，V型，纵向标准试样）≤27J；洛氏硬度最高值（HRB）≥60。

注：力学性能的规定值是指用厚度为316mm钢料纵向或横向试样测定的性能。

（4）未规定其他质量要求。

优质非合金钢是指除普通质量非合金钢和特殊质量非合金钢以外的非合金钢。

在生产过程中需要特别控制质量（例如控制晶粒度，降低硫、磷含量，改善表面质量或增加工艺控制等），以达到比普通质量非合金钢特殊的质量要求（例如良好的抗脆断性能，良好的冷成形性能等），但这种钢的生产控制不如特殊质量非合金钢严格（如不控制淬透性）。

碳素结构钢（GB/T700-1988）
2007年08月29日1.碳素结构钢（GB/1700-1988）
(1)牌号和化学成分见表3-1。

表3-1碳素结构钢的牌号和化学成分
注：F表示沸腾钢，b表示半镇静钢，z表示镇静钢，TZ表示特殊镇静钢。

①Q235A、B级沸腾钢Mn含量上限WMn=0.60%。

②沸腾钢Si含量Wsi不大于0.07%，半镇静钢Si含量Wsi不大于O.17%，镇静钢Si含量WSi限值为
0.12%。

(2)力学和工艺性能见表3-2～表3-4。

表3-2碳素结构钢的屈服点
注：Q195的屈服点仅供参考，不作为交货条件。

表3-3碳素结构钢的抗拉强度、伸长率和冲击性能
表3-4碳素结构钢的冷弯性能
注：8为试样宽度，a为钢材厚度或直径。

(3)用途见表3-5。

表3-5碳素结构钢的特性和应用。

ICS 77.140.45【1】H 40National standard of the People's Republic of ChinaGB/T 700-2006Replace GB/T 700-1988碳素结构钢Carbon structural steels(ISO 630:1995, Structural steels –Plates, wide flats, bars, sections and profiles, NEQ)Issue date: Nov 1, 2006 Implementation date: Feb 1, 2007Issued by: General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of ChinaStandardization Administration of the People's Republic of China (SAC)ForewordThis standard is not equivalent to ISO 630:1995 Structural Steels in the respect of consistency. The main differences between the two standards are as follows:-No grades are specified corresponding to the yield strength levels of 185N/mm2and 355N/mm2;-Grades Q195 and Q215 are specified corresponding to levels 195N/mm2 and 215N/mm2;-The phosphorus contents of class A steels of Q235 and Q275 are decreased by 0.005%;The thickness of Q235 class B steel is divided into two levels according to the deoxidization method and the carbon content is 0.20% in both levels;-Q235 class B steel of which the thickness is smaller than 25mm may not be subject to test with the consent of the buyer if the supplier can ensure that the impact absorbed energy is up to standard;-The yield strength of Q275 steel of which the thickness is bigger than 80mm~100mm is increased by 10N/mm2;-Cold bending test is added;-Detailed batching rules are specified according to the situation of China.This standard replaces GB/T 700-1988 Carbon Structural Steels and has the following changes in comparison with GB/T 700-1988:-Semi-killed steel is cancelled in “deoxidization method”;-Grades Q255 and Q275 in GB/T 700-1988 are cancelled;-Grade E275 in ISO 630:1995 is newly added and changed to the new grade Q275;-The lower limits of carbon and manganese contents of each grade are cancelled, and the upper limit of manganese content is increased;-The limit of silicon content of rimmed steel and killed steel is cancelled;-silicon content is changed from 0.30% to 0.35% (except for Q195);-The phosphorus and sulphur contents of grade Q195 are decreased respectively from 0.045% and 0.050% to 0.035% and 0.040%;-The regulation for the elongation after fracture of the thickness (or diameter) level of notbigger than 16mm is cancelled;-“The upper limit of the tensile strength of wide strip steel (including sheared steel plate) is not used as a term of delivery” and “Q235 class B steel of which the thickness is smaller than 25mm may not be subject to test with the consent of the buyer if the supplier can ensure that the impact absorbed energy is up to standard” are added in the footnotes of Table 2;-The regulation for the nitrogen content in the steel is modified;-The regulation for impact test is modified and the figure of the minimum impact absorbed energy of the samples of which the thickness is 5mm-10mm is added;-The basis of batching is changed from “the same furnace and kettle number”to “the same furnace number” and the limitation for the furnace number of mixed batch is cancelled. Annex A of this standard is normative.This standard was proposed by China Iron and Steel Association.This standard is under the jurisdiction of National Technical Committee for Steel Standardization. This standard was drafted by China Metallurgical Information & Standardization Institute, Capital Iron and Steel Company, Handan Iron & Steel Group and Benxi Iron & Steel Group Co., Ltd. The main drafters of this standard are Tang Yifan, Luan Yan, Wang Liping, Sun Ping, Zhang Xianfeng and Dai Qiang.This standard was first issued in January 1965, first revised in October 1979 and revised for the second time in June 1988.Carbon structural steels1 ScopeThis standard specifies the grade, dimension, shape, weight and permissible deviation, technical requirements, test methods, inspection rules, packing, marking and quality certificate of carbon structural steel.This standard is applicable to the structural hot rolled steel sheets, steel strips, sectional steels and bar steels generally used for welding, riveting and bolting engineering in delivery state.The chemical composition specified by this standard is also applicable to steel ingots, continuous casting billets, steel billets and their products.2 Normative referencesThe following normative documents contain provisions which, through reference in this text，constitute provisions of this standard. For dated references, subsequent amendments (not including corrections) to, or revisions of, any of these publications do not apply. However parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below.For undated references, the latest edition of the normative document referred to applies.GB/T 222-2006Permissible tolerances for chemical composition of steel productsGB/T 223.3 Methods for chemical analysis of iron, steel and alloy--The diantipyryl methane phosphomolybdate gravimetric method for the determination of phosphorus contentGB/T 223.10 Methods for chemical analysis of iron, steel and alloy--The cupferron separation-chrome azurol S photometric method for the determination of aluminum contentGB/T 223.11 Methods for chemical analysis of iron,steel and alloy--The ammonium persulfate oxidation volumetric method for the determination of chromium contentGB/T 223.18 Methods for chemical analysis of iron, steel and alloy--The sodium thiosulfateseparation iodimetric method for the determination of copper contentGB/T 223.19 Methods for chemical analysis of iron, steel and alloy--Theneocuproine-chloroformextraction photometric method for the determination of copper contentGB/T 223.24 Methods for chemical analysis of iron, steel and alloy--The extraction separation-dimethylglyoxime spectrophotometric method for the determination of nickel contentGB/T 223.32 Methods for chemical analysis of iron, steel and alloy--The hypophosphite reduction-iodimetric method for the determination of arsenic contentGB/T 223.37 Methods for chemical analysis of iron, steel and alloy--The indophenol blue photometric method for the determination of nitrogen content after distillation separationGB/T 223.58 Methods for chemical analysis of iron, steel and alloy--The sodium arsenite-sodium nitrite titrimetric method for the determination of manganese contentGB/T 223.59 Methods for chemical analysis of iron,steel and alloy--The reduced molybdoantimonyl phosphoric acid photometric method for the determination of phosphorus contentGB/T 223.60 Methods for chemical analysis of iron, steel and alloy--The perchloric aciddehydration gravimetric method for the determination of silicon contentGB/T 223.63 Methods for chemical analysis of iron, steel and alloy--The sodium (potassium) periodate photometric method for the determination of manganese contentGB/T 223.64 Methods for chemical analysis of iron, steel and alloy--The flame atomic absorption spectrometric method for the determination of manganese contentGB/T 223.68 Methods for chemical analysis of iron, steel and alloy--The potassium iodate titration method after combustion in the pipe furnace for the determination of sulfur contentGB/T 223.71 Methods for chemical analysis of iron,steel and alloy--The gravimetric method after combustion in the pipe furnace for the determination of carbon contentGB/T 223.72 Methods for chemical analysis of iron,steel and alloy—The alumina chromatographic separation-barium sulfate gravimetric method for the determination of sulphur contentGB/T 228 Metallic materials-Tensile testing at ambient temperature (GB/T 228-2002, eqv ISO 6892:1998)GB/T 229 Metallic materials - Charpy notch impact test (GB/T 229-1994, eqv ISO 83:1976, eqv ISO 148:1983)GB/T 232 Metallic materials--Bend test (GB/T 232-1999, eqv ISO 7438:1985)GB/T 247 General rule of acceptance, package, mark and certification for steel plates (sheets) and stripsGB/T 2101 General regulation of the checkout, package, mark and quality certificate of profiled barGB/T 2975 Steel and steel products – Location and preparation of test pieces for mechanical testing (GB/T 2975-1998, eqv ISO 377:1997)GB/T 4336 Standard test method for spark discharge atomic emission spectrometric analysis of carbon and low-alloy steel (routine method)GB/T 20066 Steel and iron--Sampling and preparation of samples for the determination of chemical composition (GB/T 20066-2006, ISO 14284:1996, IDT)3 Denotation of the grade and symbols3.1 Denotation of the gradeThe grade of steel is composed of the letter representing yield strength, value of yield strength, symbol of quality grade and symbol of deoxidization method in turn. For example: Q235AF.3.2 SymbolsQ- First letter of Chinese phonetic spelling for the “Qu” word of s teel yield strength;A, B, C, D-are respectively quality grade;F- First letter of Chinese phonetic spelling for the “Fei” word of rimmed steel;Z- First letter of Chinese phonetic spelling for the “Zhen” word of killed steel;TZ- First letters of Chinese spelling for the “Tezhen” word of special killed steel.In the denotation of grade components, symbols “Z” and “TZ” can be omitted.4 Dimension, shape, weight and permissible deviationThe dimension, shape, weight and permissible deviation of steel sheets, steel strips, sectional steels and bar steels shall meet the specification of the corresponding standards respectively.5 Technical requirements5.1 Grade and chemical composition5.1.1The grade and chemical composition (smelting analysis) of the steel shall conform to Table 1.5.1.1.1 Class D steels shall have the element with sufficiently refined grains, of which the content shall be indicated in the quality certificate. When aluminum deoxidization is used, the content of acid soluble alumnium in the steel shall not be lower than 0.015% or, alternatively, the total aluminum content shall not be lower than 0.020%.5.1.1.2 The contents of residual elements chromium, nickel and copper in the steel shall not be higher than 0.30% respectively, the nitrogen content shall not be higher than 0.008%. The contents of these elements may not be subject to analysis if they can be guaranteed by the supplier.5.1.1.2.1 The nitrogen content is allowed to exceed the value specified in 5.1.1.2. However, with every 0.001% increment of nitrogen content, the maximum phosphorus content shall decrease by 0.005%, the maximum nitrogen content obtained through smelting analysis shall not be higher than 0.012%. If the content of acid soluble aluminum in the steel is not lower than 0.015% or the total aluminum content is not lower than 0.020%, the upper limit of nitrogen content may not be limited. The elements for nitrogen fixation shall be indicated in the quality certificate.5.1.1.2.2 With the consent of the buyer, the copper content of class A steel may not be higher than 0.35%. In this case, the supplier shall analyze the copper content and indicate its content in the quality certificate.5.1.1.3 The arsenic content in the steel shall not be higher than 0.080%. For the steels smelted with arsenic mineral smelting pig iron, the arsenic content shall be specified through negotiation between both parties. If the raw material does not contain arsenic, the analysis of arsenic may not be carried out.5.1.1.4 If it can be ensured that the mechanical properties of the steel meet the specification of this standard, the carbon, manganese and silicon contents of the Class A steel of each grade may not be used as terms of delivery. However, their contents shall be indicated in the quality certificate.5.1.1.5 In case commercial continuous casting billets, steel ingots and steel billets are supplied, the lower limits of carbon and manganese contents of each grade can be specified according to therequirements of the buyer in order to ensure that the performances of rolled steels meet the requirements of this standard.5.1.2The permissible deviation of the chemical composition of steel product, continuous casting billet and steel billet shall meet the specification of Table 1 of GB/T 222-2006.The nitrogen content is permitted to exceed the specified value. However, it must meet the requirement of clause 5.1.1.2.1. The maximum nitrogen content obtained through product analysis shall not be higher than 0.014%. If the aluminum content in the steel reaches the value specified in 5.1.1.2.1and is specified in the quality certificate, the upper limit of nitrogen content may not be limited.The chemical composition deviation of the products and billets of rimmed steel is not guaranteed.5.2 Smelting methodThe steel is smelted in oxygen converteror electric furnace. The smelting method is generally selected by the supplier unless the buyer has special requirements and they are noted in the contract.5.3 Delivery stateThe steels are generally delivered in hot rolled, controlled rolled or normalized state.5.4 Mechanical property5.4.1The results of tensile and impact tests of the steel shall meet the specification of Table 2. The result of bending test shall meet the specification of Table 3.5.4.2The thickness (diameter) of the steel products made of Q195 and Q235 class B rimmed steels shall not be bigger than 25mm.5.4.3When carrying out tensile and cold bending tests, longitudinal samples shall be taken for sectional steels and bar steels, transverse samples shall be taken for steel sheets and steel strips. The elongation after fracture is allowed to be 2% lower (absolute value) than the value specified in Table 2. If the transverse sampling of narrow steel strips is limited by the width, longitudinal samples can be taken.5.4.4 Inspection may not be carried out if the supplier can ensure that the cold bending test meets the specification of Table 3. If Class A steel passes the cold bending test, the upper limit of tensile strength may not be used as a term of delivery.5.4.5 The steel products of which the thickness is not smaller than 12mm or the diameter is not smaller than 16mm shall be subject to impact test. The dimension of sample is 10mm×10mm×55mm. Through negotiation between both parties, the steels of which the thickness is 6mm-12mmor the diameter is 12mm-16mm can be subject to impact test. The dimension of sample is 10mm ×7.5mm×55mm or 10mm×5mm×55mm or 10mm×product thickness×55mm. The specified impact absorbed energy is given in Annex A. For example, if the sample of 10mm×5mm×55mm is used, the test result shall not be smaller than 50% of the specified value.5.4.6The Charpy (V-notch) impact absorbed energy shall be obtained by calculating the arithmetic mean of the single values of three samples in one group. The single value of one sample is allowed to be less than the specified value. However, itshall not be less than 70% of the specified value.If the above condition is not met, carry out the test on another three samples taken from the same product, the mean value of the six samples shall not be less than the specified value. The values of two samples are allowed to be less than the specified value. However, only one sample is allowed to be less than 70% of the specified value.The surface quality of steel products shall respectively meet the specifications of the relevant product standards for steel sheets, steel strips, sectional steels and bar steels.6 Test methods6.1 The inspection items, sampling number, sampling methods and test methods for each eatch of steel products shall meet the specifications of Table 4.6.2 In tensile and cold bending tests, the longitudinal axis of the samples of steel sheets and steel strips shall be perpendicular to the rolling direction, while the longitudinal axis of the samples of sectional steels, bar steels and narrow steel strips limited by the width shall be parallel to the rolling direction.6.3 The longitudinal axis of the impact sample shall be parallel to the rolling direction. The impact sample can reserve one rolled surface.7 Inspection rules7.1 The inspection and acceptance of the steel products shall be carried out by the technical supervision department of the supplier. The buyer has the right to carry out inspection and acceptance on any inspection item specified in this standard or the contract.7.2 The steel products shall be accepted in batches, each batch comprised of the steel products of the same grade, same furnace number, same quality grade, same variety, same dimension and same delivery state. The weight of each batch shall not be greater than 60t.For the steel products rolled with the steels smelted in the steel-making furnaces of which the nominal capacity is small, the Class A or Class B steels of the same furnace number and same grade and manufactured by the same smelting, pouring and deoxidization methods are allowed to form a mixed batch. However, the carbon content difference between the various furnace numbers of each batch shall not be bigger than 0.02%, the manganese content difference shall not be bigger than 0.15%.7.3 If the Charpy (V-notch) impact test result of the steel product does not meet the specification of 5.4.6, the sampling product shall be rejected. Take another two sampling products from the remaining part of this inspection batch and select a new group of three samples from each sampling product. The retest results of these two groups of samples shall be eligible. Otherwise,this batch of product shall not be delivered.7.4 The retest and inspection rules of other inspection items of steel products shall meet the specifications of GB/T 247 and GB/T 2101.8 Packing, marking and quality certificateThe packing, marking and quality certificate of the steel product shall meet the specifications of GB/T 247 and GB/T 2101.Annex A(Normative)Impact absorbed energy of small-sized impact sampleWidth of sample/mmImpact absorbed energy of notched sampleFigure A.1 Minimum impact absorbed energy of the samples of which the width is 5mm-10mm。