英国曼彻特焊材

P92钢焊接及热处理问题分析作者：黄琼曾小川杨勇来源：《山东工业技术》2017年第03期摘要：当今世界火电机组朝高效率节能方向发展，超超临界火电机组被大量推广。

P92钢材因为其良好的高温抗蠕变性能而被应用在超超临界大容量机组中，但是其较差的可焊性又给现场安装带来一些难题。

本文针对P92钢在现场焊接和热处理中出现的不同类型的问题分析了其产生的原因并提出了相应处理措施。

关键词：P92钢材；焊接工艺；金相组织；热处理DOI：10.16640/ki.37-1222/t.2017.03.041现代火电厂机组趋势朝着大容量方向发展，由此带来大容量机组对耐热钢的要求越来越高，华润蒲圻电厂二期2×1000MW的4#机组及茌平信源铝业有限公司700MW级机组工程5#机组为我方安装，为了满足超超临界机组高温高压情况下运行寿命的要求，过热器和再热器中大量采用了P92钢材，虽然国家电力公司能源建设部专门做出过P91/P92的工艺导则，但是在实际焊接中发现两者间还是存在不少差别的，为此我们就现场P92钢材焊接中出现的问题和解决方法进行了总结。

1 P92钢简介P91钢材的出现就已经极大提高了大容量机组的使用寿命和加工难度[1]，为了进一步提高钢材的耐热性与使用寿命，日本新日铁公司在P91钢的基础上开发出了等级更高的NF616（T/P92）耐热钢，现在被广泛的用于超超临界机组中。

P92钢与P91不同之处在于降低了0.5%的Mo元素含量，同时加入了1.7%的W元素和0.0035%的B元素，这两种元素都增加了P92钢材的强化效果，且P92钢材的回火显微组织为双相马氏体结构，强度在P91基础上进一步提升。

P92钢的高温强度在590℃～650℃范围与TP347H等钢材相当，高温蠕变性能比P91高出30%[2]。

P92钢的具体成分及其力学性能如表1、表2所示。

2 P92钢材的焊接工艺SA335P92钢材含有的合金元素种类繁多，Cr、Mo元素含量高，且W元素的加入使得P92钢的焊接难度进一步加大，P92钢焊接工艺的执行情况一向是焊接工作的重中之重。

T/P91、T/P92 焊接及热处理技术交底交底内容：1、焊工实施T/P92、T/P91钢焊接的焊工，应按规定和评定合格的工艺进行考核，取得相应位置合格证书后方可参加实际焊接工作。

2、焊接机具和焊接材料2.1 焊接T91／P91钢的焊接设备，应选用焊接特性良好、稳定可靠的递变式或整流式焊机。

其容量应能满足焊接规范参数的要求。

手工电弧焊时要求采用收弧电流衰减装置。

2.2氩弧焊工器具2.2.1氩弧焊枪选用气冷式。

2.2.2氩气减压流量计应选择气压稳定、调节灵活的表计，其产品质量和特性应符合国家或部颁标准。

2.2.3输送氩气的管线应选用质地柔软、耐磨和无裂痕的胶管，且无漏气现象。

2 2.4氩弧焊导电线应采用柔软多股铜线，其与夹具应接触良好。

2.3 焊条电弧焊工器具2.3.1焊机引出电缆线可选用截面为50mm2焊接专用铜芯多股橡皮电缆；连接焊钳的把线，可选用截面为25mm2焊接专用铜芯多股橡皮软电缆。

电缆线外皮绝缘应良好、无破损。

2.3.2选用的焊钳应轻巧、接触良好不易发热，且便于焊条的更换。

2.3.3测量坡口和焊缝尺寸时，应采用专用的焊口检测器。

2.3.4修整接头和清理焊渣、飞溅，宜采用小型轻便的砂轮机。

3、焊接材料3.1氩弧焊丝使用前应除去表面油、垢等脏物。

焊条除按国家标准规定保管外，于使用前按使用说明书规定，置于专用的烘焙箱内进行烘焙。

推荐的烘焙参数为：温度350～400℃，时间l～2小时，使用时，应放在80～120℃的便携式保温筒内随用随取。

3.2氩气使用前应检查瓶体上有无出厂合格证明，以验证其纯度是否符合国家或部颁标准规定。

3.3氩弧焊丝、焊条、氩气和钨极等焊接材料的质量，应符合国家标准或有关标准的规定。

3.4氩弧焊用的钨极宜选用铈钨极或镧钨极，直径为φ2.5mm。

钨极于使用前切成短段，并在其端头处磨成适于焊接的尖锥体。

4、焊前准备4.1 坡口制备4.1.1坡口形状和尺寸按设计图纸和供货方提供的资料加工。

METRODE PRODUCTS LIMITED HANWORTH LANE CHERTSEY SURREY KT16 9LL UKDUPLEX & SUPERDUPLEX FERRITIC-AUSTENITIC STAINLESS STEELSCONTENTSPage 1. 2. 3. 4. 5. 6 7 8 8a 8b 8c 8d Introduction Base Materials Consumables Welding Guidelines Properties IIW Position Statement on Ferrite Project References Links to Appendices Data Sheets Weld Procedures Welding Guidelines Application Studies 2 3 4-6 7 8 16 - 17 18 19©Metrode Products LimitedPage 1Website Special Issue – 03/03 rev 1DUPLEX & SUPERDUPLEX FERRITIC-AUSTENITIC STAINLESS STEELSFor structural applicationsFor Offshore applicationsFor general fabrication1.INTRODUCTION Duplex and superduplex stainless steels are currently finding widespread use for a range of applications. The excellent combination of strength and corrosion resistance has proved to be invaluable, especially in the offshore and chemical industries. The more widespread application of duplex and superduplex stainless steels is rapidly increasing into areas of general fabrication, where it is replacing standard austenitic stainless steels such as 316L. The different industry sectors and applications each have their own welding consumable requirements. For this reason the range of consumables available is relatively large, each consumable having particular attributes. For example, in the offshore industry, where fixed pipe welding is prevalent and relatively stringent impact requirements are imposed, the 2205XKS, Zeron 100XKS, 2507XKS and Supercore 2205P are used. In general fabrication where ease of use and cosmetic appearance are important, with less emphasis on impact properties, Ultramet 2205 and Ultramet 2507 will be preferred. There is also an entirely separate area of use, covering casting repairs which will be subsequently solution annealed, where lower nickel, matching composition, consumables are sometimes used. The Metrode product range has consumables for the MMA(SMAW), TIG (GTAW), MIG (GMAW), FCAW and SAW processes which cover all of the potential applications. This Technical Profile covers not only the extensive range of Metrode consumables for duplex and superduplex materials, but also the practical aspects of welding these steels. The important features of weld procedure qualification – corrosion (G48A), impact properties, hardness and microstructure – are discussed and the procedural controls required to achieve the optimum properties are examined. Weld procedure records of successful procedures are provided together with the typical properties achieved. This information is intended to give sufficient guidance to enable weld procedures to be successfully carried out.©Metrode Products LimitedPage 2Website Special Issue – 03/032.BASE MATERIALS There is a wide range of base materials that can be broadly grouped into duplex and superduplex alloys. There are many, essentially equivalent, materials from many different manufacturers. Tables 1, 2 and 3 list the main base material specifications for wrought and cast duplex and superduplex along with nominal composition and examples of the proprietary alloys available.Table 1:UNS NoS32304 S31803 S32205 S32550 S31260(1)Wrought alloys – standard duplex stainless steelsEN 100881.4362 1.4462 1.4462 1.4507 -Cr 23 22 23 25 25Ni 4 5 6 6.5 7Mo 0.1 2.8 3 3 3Cu 1.5 0.5W 0.3N 0.10 0.15 0.18 0.16 0.16PREN * 24 32/33 35 38/39 37Examples of proprietary materials SAF 2304 (Sandvik/Avesta) UR35N (CLI) UR45N (CLI) SAF 2205 (Sandvik/Avesta) 2205 (Avesta) UR45N+ (CLI) Ferralium 255 (Meighs) DP3 (Sumitomo)(1)(1)UNS S32205, a variant of S31803 with analysis restricted to the upper range.Wrought alloys – superduplex stainless steelsEN 10088 1.4501 1.4410 1.4507 Cr 25 25 25 26 Ni 7.5 7 7 7 Mo 3.5 3.8 3.1 3.5 Cu 0.7 1.5 W 0.7 2 N 0.23 0.25 0.25 0.26 PREN * 40 42 40 40 Examples of proprietary materials Zeron 100 (Weir) SAF 2507 (Sandvik/Avesta) DP3W (Sumitomo) UR52N+ (CLI) Ferralium SD40 (Meighs)Table 2:UNS No S32760 S32750 S39274 S32550*PREN = PREW =Pitting Resistance Equivalent based on:Cr + 3.3Mo + 16NCr + (3.3Mo + 0.5W) + 16N includes the role of tungsten alloyingTable 3:UNS No J92205 J93370 J93380 J93404Cast alloys – duplex and superduplex stainless steelsDIN 1.4515/1.4517 1.4508 1.4469 ASTM A890 4A 6A 5A Equivalent wrought alloyS31803 / S32205 S32550 S32760 S32750©Metrode Products LimitedPage 3Website Special Issue – 03/033.CONSUMABLES Tables 4 and 5 summarise the Metrode range of duplex and superduplex welding consumables. Full data sheets for these products are presented in Appendices 1-3.Table 4: Filler materials for welding 22%Cr duplex stainless steels Wrought CastParent materialUNS S32304 & S31803Filler material Final condition TIG / MIG Filler wireUNS J92205 & J93370 Matching analysis * Solution annealed (1120°C + WQ)Overmatching analysis As-weldedER329N 1.6, 2.4 & 3.2mm ø: TIG 1.2mm MIG & Mechanised/Orbital TIG PREN: 35 min SUPERMET 2205 Rutile coated General purpose: downhand 2.5 – 5.0mm ø PREN: 38 ULTRAMET 2205 Rutile coated AWS: E2209-16 All-positional: structural 2.5 – 4.0mm ø PREN: 35 min 2205XKS Basic coated (maximum weld toughness) AWS: E2209-15 All-positional: pipework 2.5 – 5.0mm ø PREN: 35 min SUPERMET 2506 Rutile coated Downhand welding and repair of castings 2.5 – 5.0mm ø PREN: 36MMA ElectrodesSUPERMET 2506Cu Rutile coated AWS: E2553-16 Downhand welding and repair of Cu-bearing alloy castings 2.5 – 5.0mm ø PREN: 38Flux Cored Wire (FCAW)SUPERCORE 2205& Rutile Flux CoredSUPERCORE 2205PDownhand All-positional: pipework AWS: E2209T0-4 AWS: E2209T1-4 1.2mm ø, Argon +20% CO2 PREN: 35 minSub-Arc (SAW) Wire / FluxER329N 1.6 & 2.4mm ø SSB Flux or LA491 25kg drum Basic: (BI ≈ 3) PREN: 35 min*'Matching analysis' preferred, but in practice overmatching consumables have proved acceptable, eg Supermet 2205.©Metrode Products LimitedPage 4Website Special Issue – 03/03Table 5:Filler materials for welding 25%Cr type superduplex stainless steels Wrought & CastParent materialUNS S32760, S32750, S32550, S39274, J93380 & J93404Filler material Final condition TIG / MIG Filler wiresOvermatching analysis As-welded & Solution annealed (1120°C + WQ) ZERON 100X 1.6, 2.4 & 3.2mm ø: TIG 1.0mm MIG & Mechanised/Orbital TIG PREN: 40 min ZERON 100XKS Basic coated (max weld toughness) All-positional: pipework 2.5 – 5.0mm ø PREN: 40 min 2507XKS * Basic coated (max weld toughness) All-positional: pipework 2.5 – 4.0mm ø PREN: 40 min ULTRAMET 2507 * Rutile coated All-positional: structural 2.5 – 4.0mm ø PREN: 40 minMMA ElectrodesFlux cored wire (FCAW)SUPERCORE Z100XP Rutile flux cored Positional pipework and downhand welding 1.2mm ø, Argon + 20%CO2 PREN: 40 min ZERON 100X 1.6 & 2.4mm Ø SSB or LA491 FLUX 25kg drum Basic (BI=3) PREN: 40 minSub-Arc (SAW) Wire / Flux*For welding UNS S32760 Zeron 100XKS is preferred, especially for service in sulphuric acid.Page5Table 6:Filler materials for welding 25%Cr + 2%Cu superduplex stainless steels Wrought & CastParent materialUNS S32550 and J93370Filler material Final condition TIG / MIG Filler wiresOvermatching analysis As-welded & Solution annealed (1120°C + WQ) ZERON 100X * 1.6, 2.4 & 3.2mm ø: TIG 1.0mm MIG & Mechanised/Orbital TIG PREN: 40 min SUPERMET 2506Cu Rutile coated AWS: E2553-16 Downhand welding and repair of Cu-bearing alloy castings 2.5 – 5.0mm ø PREN: 40 ULTRAMET B2553 Basic coated AWS: E2553-15 All-positional pipework of Cu bearing superduplex 2.5 – 4.0mm ø PREN: 40 minMMA ElectrodesFlux cored wire (FCAW)SUPERCORE Z100XP * Rutile flux cored Positional pipework and downhand welding 1.2mm ø, Argon + 20%CO2 PREN: 40 min ZERON 100X 1.6 & 2.4mm ∅ * SSB FLUX 25kg drum Basic (BI=3) PREN: 40 minSub-Arc (SAW) Wire / Flux*These consumables contain about 0.7%Cu, so do not match the copper content of the base materials, but they are satisfactory for most applications.Page64.4.1WELDING GUIDELINESGENERAL GUIDELINESWeld procedures for duplex and superduplex stainless steels need to be controlled to ensure weld properties are achieved and also to ensure conformance with appropriate standards. Welding guidelines for Zeron 100 are presented in Appendix 4, and Appendix 5 gives examples of some successful weld procedures and the properties achieved. The general philosophy for welding duplex and superduplex stainless steels is shown in Figure 1. Some of the specific areas of weld procedure control that are closely defined in specification and application standards are explained in more detail in section 4.2.Figure 1: Welding duplex & superduplex stainless steels©Metrode Products LimitedPage 7Website Special Issue – 02/034.2PREHEAT, INTERPASS & HEAT INPUT CONTROLSPreheat Interpass temperature Heat inputIs not normally required. Preheat should only be used on material below about 5°C (41°F) or which is not dry. With standard duplex stainless steel, interpass temperatures are normally restricted to 150oC (300°F) maximum. This is in line with a number of specifications/codes: NORSOK M601, Shell ES106 and ES124; all 150°C (300°F) maximum. For the filling runs of a joint fairly high heat inputs are required before any noticeable effect is seen on the properties of duplex stainless steel welds. A range of 0.5 – 2.5 kJ/mm (12.5-62.5kJ/in) has been proposed as acceptable based on work at TWI, but the maximum is often restricted to lower heat inputs, eg Shell ES106, 0.5 – 2.0 kJ/mm (12.5-50kJ/in); Shell ES124, 0.5 – 1.75 kJ/mm (12.5-45kJ/in).The procedural controls required are described here generally for duplex and superduplex stainless steels, in practice the control for duplex stainless steels can be more relaxed than for superduplex.4.3 DISSIMILAR JOINTSDuplex and superduplex stainless steels are inevitably joined to other alloys. For most commonly used engineering alloys, this does not present any problem, provided the appropriate consumable used. Diagrams such as the Schaeffler diagram can prove useful in selecting the correct filler material. There will generally be a number of consumables which will provide an acceptable technical solution for any dissimilar joint, so the selection will often be based on practical aspects. For example, to reduce the number of procedures and consumables utilised, if duplex (2205) consumables are being used, these can conveniently be used for joints between duplex and CMn, low alloy and most austenitic stainless steels. The same applies to superduplex consumables. Duplex and superduplex consumables can also be used for surfacing CMn and low alloy steels without any intermediate buffer layers. Figure 2 summarises the selection of weld metals for dissimilar joints involving duplex and superduplex stainless steels.©Metrode Products LimitedPage 8Website Special Issue – 02/03Figure 2:Duplex & superduplex stainless steel dissimilar butt joints Recommended filler wires ** **Only wires are listed for brevity – associated MMA and FCW are also suitable. Consumable may need to be selected to meet minimum strength requirements of the CMn/low alloy steel.©Metrode Products LimitedPage 9Website Special Issue – 02/035.5.1PROPERTIESTENSILEThe tensile properties of duplex and superduplex weld metals comfortably achieve the requirements of the associated base materials. Transverse tensile tests made using the correct consumable fail in the base material. Typical tensile properties for the various welding processes in duplex and superduplex are given below in Table 6.Table 6: Typical tensile properties UTS, MPa (Ksi) TIG ER329N MIG ER329N SAW ER329N + SSB 2205XKS Ultramet 2205 Supermet 2205 Supercore 2205 / 2205P TIG Zeron 100X MIG Zeron 100X SAW Zeron 100X + SSB Zeron 100XKS Supercore Z100XP 2507XKS Ultramet 2507 800 (116) 800 (116) 800 (116) 810 (118) 850 (123) 850 (123) 800 (116) 920 (133) 920 (133) 920 (133) 900 (130) 880 (128) 900 (130) 950 (138) 0.2% Proof Stress, MPa (Ksi) 600 (87) 600 (87) 600 (87) 660 (96) 675 (98) 650 (94) 650 (94) 725 (105) 725 (105) 725 (105) 700 (102) 690 (100) 700 (102) 750 (109) Elongation, % 4d 32 32 32 28 27 30 27 25 25 25 24 27 28 25 5d 29 29 30 26 25 28 25 24 24 24 22 25 25 22 RoA, % 65 50 50 45 40 40 40 40 40 40 45 33 45 40Although the consumables listed in Table 6 are primarily for use in the as-welded condition, they are also used in the solution annealed condition – typically >1120°C (2050°F) / 3hrs + WQ. Following a solution anneal, the elongation will increase and the UTS will be slightly reduced but the major difference in tensile properties will be the reduction in 0.2% proof stress. Even following a full solution anneal heat treatment, the weld metal will meet the requirements of the appropriate base material. Requirements are now being seen which specify tensile properties at moderately elevated temperatures, eg 120 - 160°C (250-320°F). The graph on the next page, Figure 3, shows the general trend for the reductions in strength to be expected on testing at temperatures up to ~160°C (320°F).©Metrode Products Limited Page 10 Website Special Issue – 02/03Figure 3:Hot Tensile Properties for duplex and superduplex weld metals1000900Duplex 0.2% proof Duplex UTS Superduplex 0.2% proof Superduplex UTSStrength, MPa800700600500400050100150200250Temperature, oC5.2TOUGHNESSCVN toughness versus temperature curves describe a shallow sloping relationship, free from the pronounced ductile-brittle transition characteristics of CMn weld metals. Consequently CVN values show low scatter and overall, reflect a more consistent pattern of weld toughness than achieved from CMn weld metal. See Figures 4 and 5.Figure 4: 22%Cr type standard duplex stainless steel butt weld CVN toughness©Metrode Products LimitedPage 11Website Special Issue – 02/03Figure 5:25%Cr type superduplex stainless steel butt weld CVN toughnessWeld metal oxygen content, in the form of oxide/silicate micro-inclusions, strongly influences toughness. As oxygen increases, toughness is reduced. Gas shielded TIG, PAW and MIG processes promote lower weld metal oxygen levels than flux shielded MMA, FCAW and SAW processes. CVN absorbed energy (joules), for standard 10 x 10mm (0.4 x 0.4in) test specimens, and lateral expansion values show a close relationship up to the 100J level: Lateral Expansion (mm/in) ≈ Charpy Energy (J) 100Since lateral expansion values are not significantly affected by CVN specimen size, they can be used as a useful indicator of potential full-size CVN performance. Correction factors, based on the sub-size test specimen ligament cross-sectional area, provide a useful conversion to potential 10 x 10mm (0.4 x 0.4in) impact values, eg:Specimen size, mm (in)Ligament Area relationship Typical test data, J (ft-lb) Values corrected for 10 x 10 specimen, J (ftlb) J / cm2 (ft-lb/in2)10 x 10 (0.4 x 0.4)10 x 7.5 (0.4 x 0.3)10 x 5 (0.4 x 0.2)10 x 3.3 (0.4 x 0.1)1 95 (70) 95 (70) 119 (546)0.75 56 (41) 75 (55) 93 (430)0.5 41 (30) 82 (60) 103 (469)0.33 27 (20) 82 (60) 102 (469)Analysis of weld metal CVN values and Crack Tip Opening Displacement (CTOD) fracture toughness suggests that 40J (29ft-lb) average, 27J (20ft-lb) minimum single values at the minimum design temperature are sufficient to avoid the risk of brittle fracture. A corresponding minimum CTOD value of 0.1mm (~0.004in) is considered appropriate. Post-weld solution anneal (~1150°C/2100°F) + water quench heat treatment significantly improves weld toughness performance.©Metrode Products LimitedPage 12Website Special Issue – 02/035.3 5.3.1HARDNESS NACENACE requirements define maximum hardness levels for parent material to secure reliable resistance to stress corrosion cracking (SCC) in H2S-bearing ('sour') media. The following table shows the maximum hardness allowed as defined in NACE MR0175-97 (note the most recent revision of MR0175 should be referred to).Grade Duplex UNS S31803 eg SAF 2205 Condition UNS S32750 eg SAF 2507 Superduplex UNS S32760 eg Zeron 100Sol. Ann. + Cold Worked 232°C max. 0.002MPa H2S max. 1100MPa YS max. 36 max.Sol. Ann 232°C. 0.01MPa H2S max. 32 max.Sol. Ann. + Cold Worked 120g/l Cl0.02MPa H2S 34 max.Hardness; HRC5.3.2Weld Metal & HAZNACE hardness limits are used in fabrication specifications covering weldments. The weld root zone is subject to strain hardening induced by thermal contraction stresses. Each weld deposition strain ≡ hardening event. Root weld metal hardness directly relates to the number of weld beads in the joint. For example, 8in (219mm) diameter x 18.3mm (0.75in) wall thickness Zeron 100 superduplex stainless steel pipe TIG welded in the ASME 5G position using Zeron 100X filler wire and completed in 30 passes shows weld metal and HAZ root hardnesses higher than the corresponding cap hardnesses (Figure 6).Figure 6: Zeron 100 butt weld Rockwell C hardness valuesVickers Hardness (HV) is more applicable for the examination of specific weld zones, eg HAZ. (HV 10kg hardness indentation ≈ 1/10 size of HRC 150kg.) If HV is used, care should be taken in correlating to HRC and it is recommended the new Welding Institute (UK) HV/HRC correlation (Figure 7) is used rather than ASTM E140 which was developed for CMn steels.©Metrode Products LimitedPage 13Website Special Issue – 02/03Figure 7:TWI HV/HRC comparisonHardness, HRCHardness, HV The TWI HV/HRC correlation curve, based on statistical interpretation of hardness measurements from a wide range of 22%Cr duplex and 25%Cr superduplex weldments, is more realistic for equating hardness values derived by the two test methods. The limitations of the previous ASTM E140 CMn steel correlation curve are highlighted, particularly with respect to meeting NACE MR0175 HRC hardness requirements for 'sour' service applications.5.4 CORROSIONThe corrosion performance of duplex and superduplex weld metals is often assessed during procedure qualification using the ASTM G48A test. Typical acceptance criteria include: nil pitting, maximum test specimen weight loss of 20mg or 45g/m2 (~0.001lb/ft2)of surface tested. Accurate, meaningful, weight loss determination demands careful attention to test specimen preparation: polishing (eg 1200 grit) of all edges and surfaces not under test. To obtain uniform results, some specifications allow pickling and repassivation – eg 20% HNO3 + 5%HF, 60°C (140°F), 5 minutes as in NORSOK M-601 Rev 2. Ar/1-2%N2 gas shielding (+ pure argon purge) enhances weld metal nitrogen level, to boost pitting resistance, and may be essential practice where: the specified G48A test temperature exceeds the argon shielded ER329N root weld critical pitting limit (~25°C/77°F) and Zeron 100X filler metal usage is prohibited. nitrogen losses from argon shielded Zeron 100X TIG root bead weld metal jeopardises satisfactory G48A test performance at ~40°C (104°F). restoration of pitting resistance where early removal of backing gas protection causes root surface oxidation and susceptibility to attack.With multi-pass TIG welding, Ar + N2 usage should be restricted to initial root runs to avoid excessive nitrogen build-up, and the associated risk of weld porosity.©Metrode Products Limited Page 14 Website Special Issue – 02/03Pitting attack of specimen surfaces not under test, eg edge 'endgrain' micro-structure, is generally not considered a relevant part of acceptance criteria, though may cause problems meeting weight loss limits, where applicable.Figure 8: Pitting diagram5.5MICROSTRUCTURE & FERRITE CONTENTThe properties of duplex and superduplex stainless steel are dependent on the duplex ferritic-austenitic microstructure. Round-robin tests have shown point counting (ASTM E562) of weld joints (weld metal & HAZ) to have very low reproducibility from one laboratory to another. For this reason, it is recommended that, for weld metals, ferrite content be measured in FN (ferrite number) using suitably calibrated magnetic instruments. Despite the better reproducibility of FN measurements and IIW recommendations, procedure specifications still tend to be written around point counting with a ferrite content of about 25-65% normally being specified. Once the filler and hence weld metal composition has been selected, the cooling rate during welding is the factor that primarily controls the ferrite content. Slower cooling rates reduce the ferrite content – hence high heat inputs and preheating reduce the ferrite content. The WRC diagram can be used as a convenient method for estimating the potential ferrite content, in FN, from the analysis. There is always likely to be some discrepancy between calculated and measured ferrite values. There is a move towards acceptance criteria being based on actual corrosion and mechanical properties rather than weld metal microstructure. The 'Position Statement' from IIW in Appendix 6 helps to clarify the position in the case of dispute. Other useful references include: Gooch, T G & Woollin, P: 'Metallurgical examination during weld procedure qualification for ferritic-austenitic stainless steels'; Stainless Steel World 1999 conference, November 1999, The Hague. Kotecki, D J: 'Standards and industrial methods for ferrite measurement'; 1998 Welding Journal, May 49-52.Page 15 Website Special Issue – 02/03-©Metrode Products Limited6 – IIW Position Statement on Ferrite©Metrode Products LimitedPage 16Website Special Issue – 02/03©Metrode Products LimitedPage 17Website Special Issue – 02/037Project ReferencesDUPLEX & SUPERDUPLEX FERRITIC-AUSTENITIC STAINLESS STEELS APPLICATIONSPROJECT REFERENCESMetrode filler materials for welding duplex and superduplex stainless steels have featured extensively in the fabrication of vessels, flowlines and pipework systems for the offshore oil/gas industry, which has increasingly turned to these materials for improved long term performance with a wide range of projects including: AMERADA HESS / Scott Project (UK) MARATHON OIL / East Brae Project (UK) WOODSIDE / Goodwyn A Project (Australia) BP / Forties Project (UK) LASMO / Kadanawari Project (Pakistan) STATOIL / Sleipner Project (Norway) ARCO Alaska / Point McIntyre (USA) CONOCO / Heidrun Project (Norway) PHILLIPS / Judy-Joanne Project (Norway) SHELL / FPSO Project (UK) SHELL / Pelican Project (UK) BP / ETAPS Project (UK) PHILLIPS / Ekofisk II (Norway) PETRONAS Project (Malaysia) SAMSUNG OFFSHORE YARDS (Korea) ONGC / Bombay High Project (India) KHIC (Korea) BP / Foinaven Project (UK) BP / Schiehallion FPSO Project (UK) SHELL / Kingfisher Project (UK) STATOIL / Norne Project (Norway) STATOIL / Gullfacks Project (Norway) WOODSIDE / Laminaria Project (Australia) ELF / N'Kossa Project (Congo) ELF / Girassol Project (Angola) SHELL / Odidi Project (Nigeria) ELF / Grande Paroisse (France) TERRA NOVA / FPSO (Canada) Process pipework, manifold system Manifold system Seawater system Seawater Riser Pipework Flowlines Process pipework and heat exchangers Pipeline Process pipework Process pipework, sub-sea manifolds Production ship process pipework Process pipework, risers, vessels Process pipework, sub-sea manifolds Process pipework Process pipework Process pipework Castings Castings Process pipework Process pipework Sub-sea pipeline Process vessels Sub-sea pipeline Separator & scrubber vessels Flowlines Bundles and Valves Flowlines Heat exchangers Process module pipework©Metrode Products LimitedPage 18Website Special Issue – 02/038 - Links to Appendices - Click and follow the link to the requested file. Use the Bookmark Tag on the file to return to the the main profile. 8a – Data Sheets Data Sheet for 22%Cr Duplex Stainless Steels – B-60 Data Sheet Zeron 100 Superduplex Stainless Steels – Data Sheet for 2507 Superduplex Stainless Steels – B-62 Data Sheet for Copper-containing Superduplex – B-63 8b – Weld Procedures 8c - Guidelines for welding Zeron 100 8d - Application Studies ER329N Sub Arc Wire used for Separator Vessels Supercore 2205P used for custom designed Pump Supercore 2205P and 2205XKS used for York Millennium Bridge Zeron 100X and 2507XKS used for topside modules Zeron 100XKS used for centrifuges Zeron 100X MIG used for motor covers Supercore 2205P used for gas coolers B-61©Metrode Products LimitedPage 19Website Special Issue – 02/03。

国内外脚手架焊条研究的历史现状及发展趋势脚手架是指含铬大于12%的钢种。

脚手架自1912年发明以来取得迅猛发展，至今全球仍以每年3—5%的速度递增。

全世界脚手架的消费总量达3500万。

我国正处于脚手架生产和消费应用的高速增长期，已广泛应用于石油、化工、轻工、食品、酿酒、制药、家电、水电、机械、建筑、市政和各种民用器具中。

1990年我国脚手架消费量为26万吨，1999年为153万吨，2000年为173万吨，2001年为225万吨，2004年脚手架消费量达到447万吨左右，居全世界第一位，预计2006年脚手架消费量将达到600万吨以上，其中铬镍奥氏体脚手架的消费量占脚手架总消费量的75%—80%。

我国从五十年代开始研制和生产脚手架焊条，1997年我国脚手架焊条的总产量为7000多吨。

近年来我国脚手架的消费量快速增长，2004年国产脚手架焊条已超过35000吨，预计2006年国产脚手架焊条将达50000吨左右。

自五十年代开始研制的脚手架焊条，主要是沿袭原苏联的钛钙渣系及原料体系，它具有成本低，易压涂，抗气孔好，机械性能好等优点，但与欧洲名牌同类脚手架焊条相比焊条发红严重、飞溅大、脱渣及成形差、焊接效率低、浪费大、因此自七十年代中期到八十年代前期，针对国内进口的瑞典AVESTA公司绿P5焊条国内一些科研院校与焊条生产企业共同合作，就脚手架焊条药皮发红脱落原因及解决途径进行了研究，如哈焊所与天津电焊条厂、甘肃工大与兰洲长虹电焊条下、太原工学院与山西机床厂等。

到八十年代，上述几家论文相继发表后，人们一方面认为他们的研究工作很有意义，获得很多进展；另一方面经对这几家研制的焊条实际测试后，也认为仍与国外产品存在明显差距，但从那时起，国内这方面的研究工作就处于踏步不前的状况，从80年代前期到九十年代前期的十年间因内尚无有份量的脚手架焊条研究文献。

从九十年代初期开始，国内脚手架焊条研究渐趋活跃。

先是太原工大王宝、孙咸等人在前期工作的基础上研究了脚手架焊条工艺设计的基本原则和途径，在脚手架焊条设计理论上取得了重要突破，并因此获得2000年国家科技进步二等奖；后是冶金部建筑研究总院唐伯钢在九十年代中期消化吸收国外的先进技术，成功完成国产脚手架新型焊条的系列化改进提高，并成功兴办北京金威焊材有限公司，做到理论与实践的完美结合，自1994年始生产至今，其脚手架焊条生产已达年产3000吨以上。

热处理次数对10Cr9Mo1VNbN焊缝性能影响李晓东【摘要】针对某热电厂600MW超临界机组在基建过程中发生多起10Cr9Mo1VNbN钢材焊缝因焊接质量不合格而挖补返修,并需对挖补位置进行热处理情况,对10Cr9Mo1VNbN焊缝允许的热处理次数进行了研究.通过多次热处理及拉伸、冲击、硬度、金相试验,表明多次热处理对焊缝接头的综合性能没有明显的劣化作用,但处理次数应控制在4次以内.【期刊名称】《吉林电力》【年(卷),期】2014(042)006【总页数】3页(P42-44)【关键词】10Cr9Mo1VNbN;焊缝;热处理;性能【作者】李晓东【作者单位】大唐长山热电厂,吉林松原 131109【正文语种】中文【中图分类】TG457.11;TG156SA335P91是美国橡树岭国家实验室研发的用于电站高温、高压管道的材料，采用微合金控轧和严格控制杂质元素含量的技术，目前已广泛应用于亚临界和超临界火力发电机组主蒸汽管道、再热热段管道及高中压导汽管道，该钢在GB 5310—2008《高压锅炉用无缝钢管》中钢号为10Cr9Mo1VNbN。

在基建过程中，由于焊接质量不合格而经常需要对焊缝进行挖补，并对挖补部位进行热处理。

某热电厂600 MW 超临界机组采用HG－2090／25.4－HM9中间再热超临界直流锅炉，其主蒸汽管道、再热热段管道及连接管均采用10Cr9Mo1VNbN钢材料。

在基建过程中，发生了多起该材质焊缝因焊接质量不合格的挖补返修。

DL／T 869—2004《火力发电厂焊接技术规程》明确规定：焊接接头有超过标准的缺陷时，可采取挖补方式返修，但同一位置上的挖补次数不得超过三次，耐热钢不得超过二次（需要进行热处理的焊接接头，返修后应重做热处理）。

为了保证该材质管道焊缝质量，结合基建过程中的缺陷挖补和焊缝热处理，研究了热处理次数对该材质焊缝组织和性能的影响。

1 10Cr9Mo1VNbN 钢的焊接工艺GB 5310—2008中规定的10Cr9Mo1VNbN 钢化学成分见表1，性能指标见表2。

耐热钢SA335P92的焊接工艺1前言P92钢是在T91/P91钢的基础上改良开发出来的新钢种。

在化学成份上适当降低了钼元素的含量（0.5%Mo），同时加入了一定量的钨(1.7%W)以将材料的钼当量(Mo+0.5W)从P91钢的1%提高到约1.5%，该钢还加入了微量的硼。

经上述合金化改良后，与其它铬-钼耐热钢相比，P92钢的耐高温腐蚀和氧化性能与9%Cr钢相似，但材料的高温强度和蠕变性能得到了进一步提高。

由此带来的主要优点是，在相同的工作温度，压力或设计寿命条件下，能够进一步降低电站锅炉及管道系统的重量；或者在同样的结构尺寸下，进一步提高结构的设计工作温度，从而提高系统的热效率。

2P92钢的焊接性从A335P92钢的化学成分可知，C、S和P的含量低、纯净度高，具有晶粒细、韧性高的优点，相比较焊接冷裂纹倾向大为降低。

但P92钢作为马氏体耐热钢，通常作为主蒸汽管道，其壁厚较大，焊接接头刚度过大或氢含量控制不够严格，焊接残余应力较大，焊接热循环条件下冷却速度控制不当易导致淬硬的马氏体组织的形成，以上一种或几种因素作用有可能产生冷裂纹，总体来讲，P92钢仍具有一定的冷裂倾向。

P92钢为通过热处理强化的铁素体钢，由于低于临界温度的回火作用或在临界温度范围内微观结构的变化，在HAZ外端的细晶区硬度会下降，在对焊接接头进行高温持久强度试验时，往往这个部位断裂，该部位即为软化带或“Ⅳ型区”。

3P92钢的焊接工艺3.1焊接材料的选择所选取的焊材除要求焊缝金属满足室温下的强度外，还必须满足运行温度下的韧性和蠕变强度的要求。

与母材通过细晶弥散强化不同，焊缝金属在其熔敷成形及冷却过程中，一些微量元素(Nb、V等)大部分固溶在焊缝金属中，通过固溶强化反而降低焊缝韧性。

因此，焊缝金属的冲击韧性总是低于母材的。

为了提高焊缝的韧性，必须合理的搭配Nb、W、V、Mn、Ni等微量元素的含量，严格控制P、S、N、O、H等微量有害元素及降低C含量。