PACKER ENGINEERING INC,
1950 North Washington Street,
Naperville, IL 60566
Metallurgical Evaluation of a DOT-3AA Cylinder,
Serial No. 441106, with Pin Hole Leak
FINAL REPORT
June 2007
Prepared for
Mark Toughiry
Office of Hazardous Materials Technology
Pipeline and Hazardous
Materials Safety Administration
U.S. Department of Transportation
Purchase Order No. DTPH56-07-P-000007
This document was prepared under the sponsorship of the U.S. Department of Transportation. Neither the United States Government nor any Person Acting on behalf of the United States Government assumes the responsibility resulting from the use or publication of information contained in this document or warrants that such use of publication of the information contained in this document will be free from privately owned rights.
Table of Contents
1.0 Introduction (3)
1.1 Technical Approach (3)
2.0General Documentation of the Cylinder (4)
2.1Visual Documentation and Cylinder Specifications (4)
2.2Non Destructive Evaluation (4)
3.0Metallurgical Analysis (5)
3.1Visual Observation and Sectioning of Cylinder (5)
3.2Chemical Analysis of the Cylinder (5)
3.3Fractography and Metallography (6)
4.0Mechanical Property Evaluation (7)
4.1Tensile Test (7)
4.2Rockwell Hardness Test (8)
4.3Microhardness Evaluation (9)
5.0Discussion (10)
6.0Conclusion (11)
7.0Figures (12)
8.0 References (31)
1.0 INTRODUCTION
Objective: - The purpose of this project is to determine chemical and metallurgical characteristics of the cylinder with a leak, initial point of fracture and possible cause of leak.
Approach
1.1 Technical
In this project the DOT – 3AA cylinder with serial number 441106 was analyzed to determine the chemical and metallurgical characteristics of the leak.
The general condition of the cylinder was documented. The location of the leak was identified and documented. Radiography was performed on the cylinder to characterize and confirm the location of the leak. Ultrasonic inspection was performed to characterize the length of the crack and thickness of the cylinder near the crack. After performing the non-destructive testing, the cylinder was cut open. The inside surface of the cylinder was documented. Chemical analysis was performed on a sample removed from the cylinder. Magnetic particle testing was performed on the identified leak location to confirm the size of the crack. The cylinder was cut open to perform fractographic analysis on the leak surface. The fracture surface was documented using a stereomicroscope, before cleaning the oxide scale. An Energy Dispersive Spectroscopy (EDS) analysis was performed on the uncleaned fracture surface. The fracture surface was cleaned using ultrasonic cleaning and replica strip cleaning technique. The cleaned fracture surface was analyzed using the scanning electron microscope. After completing the fractographic analysis the sample was cut perpendicular to the fracture surface and the microstructure was analyzed and compared to the microstructure of the sample cut in the same grain direction but away from the fracture surface. Microhardness was measured on both samples. Rockwell hardness was measured along the length of the largest piece of the cylinder using ASTM E-18-98. A tensile test was performed to measure the strength and ductility of the ruptured cylinder in accordance with 49 CFR 178.37- K and L.
2.0 GENERAL DOCUMENTATION OF THE CYLINDER
2.1 Visual Documentation and Cylinder Specifications
The cylinder was identified as a DOT - 3AA cylinder with serial number 441106 as shown in Figure 1. The indented markings on the cylinder are as shown in Figure 2.
?The cylinder is marked as DOT – XXXXXXX GL Limited 441106. 119501 6
A 06 TP377 5PSI 11566 VA3.3.
?As per the information provided to Packer Engineering Inc by DOT, the service pressure of the cylinder is 2,265 psi. The minimum design wall
thickness is 0.228 inch.
?The maximum diameter of the cylinder is 9 inches as measured by Packer Engineering Inc.
?The surface of the cylinder appears to be sandblasted.
? A surface flaw was observed in the transverse direction of the cylinder as shown in Figure 3. It is located 16.5 inches from the bottom of the cylinder. A
higher magnification image of the surface flaw is as shown in Figure 4.
2.2Non Destructive Evaluation
X-ray radiography was performed on the cylinder to characterize the surface flaw on the cylinder. The cylinder was radiographed in two different orientations. The first orientation consisted of a longitudinal view of the cylinder with the source perpendicular to the outer surface at the flaw location. The radiograph in Figure 5 indicates that it is not simply a surface flaw, but that the flaw penetrates a significant portion of the cylinder wall. The second orientation was in the transverse direction with the source at a 45 degree angle to the defect. The radiograph in Figure 6 also shows the defect and confirms that it is not just a surface flaw.
Pressure testing was performed on the cylinder using air to confirm the presence of the leak. The cylinder was connected to a portable air compressor with a test gauge and regulator in-line between the compressor and the cylinder. Gas Leak Detector (soap solution) was applied on the cylinder surface and pressure was slowly applied. At approximately 5 psi, bubbles were visible from the area of the surface flaw. The test was continued up to approximately 20 psi, at which air could be felt escaping through the flaw. No other leak was detected in the cylinder. This test was repeated two times to confirm the findings.
Ultrasonic inspection was performed to analyze the leak and thickness variation of the cylinder along the length. Figure 7 shows the ultrasonic testing of the cylinder. The shear wave analysis at the leak using 5mHz, 45o shoe, ?” diameter from 180 o back indicates the depth of the crack is 0.158 inch as indicated by Figure 8. The maximum depth of the crack is 0.174 inch as shown in Figure 9. The maximum length of the crack determined by ultrasonic inspection was 0.63 inch. The thickness of the cylinder was analyzed using
shear wave around the circumference of the cylinder containing the crack. Table I lists the thickness measurements along the cylinder length in the plane that contains the leak. The wall thickness 3 inches above the bottom of the cylinder is 0.242 inch. The wall thickness near the crack is 0.244 inch. These thickness measurements indicate that the wall thickness of the subject cylinder meets the 0.228 inch minimum design requirement.
TABLE I
Thickness measurement along the length of the cylinder
# Distance of the cylinder from bottom (inch) Thickness along the length of cylinder and in the plane containing leak (inch)
1 3 0.242
2 12 0.243
3 16 0.244
4 24 0.246
5 3
6 0.253
6 46 0.255
3. METALLURGICAL ANALYSIS
3.1 Visual Observation and Sectioning of the Cylinder
Figure 10 shows the location at which the cylinder was sectioned. Figure 11 indicates the presence of corrosion products on the inside wall of the cylinder. The inside surface at the leak is as shown in Figure 12. The samples for tensile testing and chemical analysis were sectioned from the area marked in Figure 13 and Figure 14. The arrows shown in the Figure 13 and Figure 14 indicate the leak location. The cylinder was sectioned as shown in Figure 15 to cut open the leak. Fractography and metallograhy were performed on one surface of the leak and the other side of the leak was retained.
3.2 Chemical Analysis of the Cylinder
The chemical analysis of the subject DOT-3AA cylinder with serial number 441106 was compared to the steel materials authorized for DOT-3AA cylinders by the Code of Federal Regulations (CFR) 49, Chapter I – Research and Special Programs Administration, Department of Transportation, Subchapter C- Hazardous Material Regulations, part § 178.37. The comparison is as shown in Table II. The composition of the subject DOT-3AA cylinder meets the specifications for 4130X steel.
TABLE II
Comparison of the chemistry of the subject DOT cylinder with steel authorized for
DOT-3AA cylinder as per 49 CFR part § 178.37
Designation Elements
Subject
DOT
cylinder
(%) 4130X (%) NE8630 (%) 9115 (%) 9125 (%) Carbon-Boron (%) Intermediate Manganese (%)
Carbon
0.31 0.25/0.35 0.28/0.33 0.10/0.20 0.20/0.30 0.25- 0.37 0.40 max Manganese
0.58 0.40/0.90 0.70/0.90 0.50/0.75 0.50/0.75 0.80-1.40 1.35/1.65 Phosphorus
0.011 0.04 max 0.04 max 0.04 max 0.04 max 0.035 max 0.04 max Sulfur
0.008 0.05 max 0.04 max 0.04 max 0.04 max 0.045 max 0.05 max Silicon
0.27 0.15/0.35 0.20/0.35 0.60/0.90 0.60/0.90 0.3 max 0.10/0.30 Chromium
0.84 0.80/1.10 0.40/0.60 0.50/0.65 0.50/0.65 - - Molybdenum
0.17 0.15/0.25 0.15/0.25 - - - - Zirconium
- - - 0.05/0.15 0.05/0.15 - - Nickel
0.02 - 0.40/0.70 - - - - Boron
- - - - - 0.005/0.003 - Copper
0.03 - - - - - - Aluminum
0.04 - - - - - -
3.3 Fractography and Metallography
The cut section of the cylinder was observed under stereomicroscope at up to 60 X magnification. Figures 16 -18 show the stereoscope images of the section containing fracture. The surface of the as-received fracture appears to be corroded as indicated in Figure 18. The EDS analysis of the as-received fracture surface is shown in Figure 19. It indicates presence of iron (Fe), chromium (Cr), silicon (Si), carbon (C) oxygen (O), sulfur (S), silicon (Si), aluminum (Al), copper (Cu), chlorine (Cl), nickel (Ni) and sodium (Na). The fracture surface was then cleaned using replica strip cleaning, ultrasonic cleaning and rinsing with acetone. Even after cleaning several times, the fracture surface had an adherent oxide layer. The cleaned fracture surface was observed using scanning electron microscopy (SEM). Figures 20-22 show the fracture surface at the ID, center and OD of the cylinder wall respectively. As seen in the figures, the details of the fracture are obscured by oxides.
In order to perform metallographic analysis, the section containing fracture surface (Sample A) was cut perpendicular to the fracture and compared to the microstructure of the sample cut in the same grain direction but away from the fracture surface (Sample B). The metallurgical mounts were prepared by polishing and etching with 2% Nital solution.
Sample A (containing fracture surface):
The micrographs across the fracture surface can be seen in Figures 23 to 29. Figure 24 indicates presence of oxide layer on the fracture surface and also indicates presence of copper-colored phase. Figure 30 shows that the overall microstructure across the cylinder wall is tempered martensite. However, the microstructure at the periphery of both OD and ID of the cylinder wall indicates decarburization in some areas as seen in Figures 31 and 32 respectively. Two crack-like areas can be seen at the OD of the cylinder wall as shown in Figure 31. They are non-propagating and not related to the fracture of the cylinder.
Sample B (away from fracture surface):
The overall microstructure of the sample taken away from fracture surface is also tempered martensite as shown in Figure 33. Also there was decarburization observed at the ID of the sample as shown in Figure 34.
An EDS analysis was performed to evaluate the composition of the copper-colored phase and the dark and light gray oxide layer. Three areas at the fracture surface were analyzed as shown in Figure 35. The EDS at Location 1 and 2 and 3 are shown in Figure 36, 37 and 38, respectively. EDS at Location 1 indicates presence of copper (Cu), aluminum (Al), tin (Sn) and iron (Fe). The EDS at Location 2 (dark gray) shows presence of iron (Fe), chromium (Cr), silicon (Si), sulfur (S), chlorine (Cl), copper (Cu) and oxygen (O). The EDS at Location 3 (light gray) indicates that iron (Fe), manganese (Mn) and oxygen (O) are present.
4 MECHANICAL PROPERTY EVALUATION
4.1Tensile Test
Tensile sample was obtained from the location as shown in Figure 13. The testing was performed in accordance with 49 CFR 178.37-K and L. The results are as shown in Table III. The tensile properties of the subject DOT-3AA cylinder were compared to the mechanical properties of 4130 steel at tempering temperatures of 1000 oF and 1200 oF [2]. Part 178.37 of 49 CFR (g) (4) indicates that the minimum tempering temperature may not be less than 1000 oF. Hence, the tensile test results were compared to only the values listed at 1000 oF and above. As seen in the table, the tensile properties of the subject DOT-3AA meet the specifications as notes above.
TABLE III
Tensile test results of DOT-3AA cylinder compared to the tensile
properties of 4130 steel
Property DOT-3AA
cylinder
4130 Steel
(Tempered at 1000 oF)
[ref 2]
4130 Steel
(Tempered at 1200 oF)
[ref 2]
Tensile Strength 125 ksi 150 ksi 118 ksi
Yield Strength
(0.2% offset)
110 ksi 132 ksi 102 ksi
% Elongation in
2 inches
20% 17% 22%
4.2 Rockwell Hardness Test
The Rockwell Hardness Test was performed along the largest piece of the cylinder in accordance with ASTM E18-98. The hardness tester was calibrated using a Patriot Manufacturing Company standard block with serial number 00B5167 and standard hardness value of 32.3 +/- 1.0 HRC. The hardness measured using the standard block was
33.2 at the beginning of the test and 32.0 at the end of the test. The results are as shown
in Table IV. The hardness values of 4130 steel at tempering temperatures of 1000 oF and
1200 oF are 34 HRC and 24 HRC respectively [2]. The hardness of the DOT-3AA cylinder indicates that it was tempered above 1000 oF.
Table IV
Rockwell hardness results of the DOT-3AA cylinder compared to the hardness
values of 4130 steel
Location DOT-3AA
cylinder
(HRC)
4130 Steel
(Tempered at 1000 oF)
(HRC)[ref 2]
4130 Steel
(Tempered at 1200 oF)
(HRC) [ref 2]
1 28
2 27
3 26
4 27
5 27
6 26
34 24
4.3 Microhardness Evaluation
The microhardness was evaluated for the metallurgical mounts prepared across the fracture surface and away from the fracture using ASTM E92 - 03. The results are indicated in Table V and Table VI. The average hardness at about the center of the cylinder wall thickness is similar for both samples. However, the average hardness at the OD and ID is closer to the fracture surface, which is most likely due to decarburization.
TABLE V
Hardness measurements close to the fracture surface
# Distance From OD (inches) Hardness (HRC) Average (HRC)
1 0.007 (Close to OD) 22
21
2 0.014 (Close to OD) 21
3 0.021 (Close to OD) 21
(center) 26
4 0.112
25
(center) 25
5 0.119
(center) 24
6 0.126
7 0.217 (Close to ID) 19
8 0.224 (Close to ID) 22
21
9 0.231 (Close to ID) 22
TABLE VI
Hardness measurements away from fracture surface
# Distance From OD (inches) Hardness (HRC) Average (HRC)
1 0.007 (Close to OD) 26
26
2 0.014 (Close to OD) 26
3 0.021 (Close to OD) 27
(center) 25
4 0.112
26
(center) 26
5 0.119
6 0.126
(center) 27
7 0.217 (Close to ID) 22
25
8 0.224 (Close to ID) 26
9 0.231 (Close to ID) 27
5 DISCUSSION
Metallurgical evaluation was performed on the DOT - 3AA cylinder with serial number 441106 to identify the cause and origin of the leak. The leak was located 16.5 inches from the bottom of the cylinder. The presence of a leak was confirmed using non-destructive techniques such as radiography, pressure testing and ultrasonic testing. The leak was oriented in the transverse direction. Hence, hoop stresses created by internal gas pressure cannot be responsible for the rupture.
The composition of the DOT - 3AA cylinder meets the specifications for 4130X steel as given in 49 CFR, part § 178.37. The tensile strength, yield strength, elongation and hardness of the DOT - 3AA cylinder indicate it was tempered above 1000o F as required in 49 CFR, part § 178.37 (g) – 4.
Metallography and EDS of the fracture surface showed that a copper-rich phase containing a small amount of tin is present along the grain boundaries near the fracture and in the oxide on the fracture surface. The copper-tin phase most likely represents the remnants of a bronze-type material that came into contact with the cylinder while the cylinder was near its hot deformation temperature. The bronze material melted and was included into the steel. Based on the presence of copper and tin, and the apparent lack of elements such as zinc, aluminum, nickel and lead, it may be speculated that a phosphor bronze material contacted the cylinder. However, the precise identification of the copper-bearing material is not significant for determination of the process by which the leak formed in the subject cylinder.
If the bronze material entered the molten 4130X alloy, the bronze would likely have dissolved and become distributed throughout the billet. However, the nominal copper content of the cylinder was determined to be 0.03%. Bulk copper concentration at 0.03% would not be considered to be elevated, or high enough to cause cracking. Finally, copper-rich phases in grain boundaries were not seen in the microstructure away from the fracture. Therefore, the bronze material most probably did not enter the molten steel alloy.
The recommended temperatures for hot deformation processes such as forging or extrusion generally range from 1600o F to 2245o F for 4130 [3]. The liquidus temperature for phosphor bronze alloys generally ranges from 1800-1920o F (The liquidus for pure copper is 1950o F.) [4]. Note that the recommended austenitizing temperature for 4130 is 1600o F which would be too low to melt bronze or pure copper. Therefore, the inclusion of the copper alloy into the cylinder must have occurred during hot deformation. Based on the observation that the crack was wider at the OD of the wall compared with the ID, it is likely that the crack was initiated by inclusion of copper at the OD and propagated toward the ID.
The thick oxide layers on the fracture surface of the leak indicate the crack was open during hot deformation and subsequent heat treatment. The presence of copper phases in
the oxide layers indicates the bronze component was molten as the oxide films were forming during hot deformation.
Cracking of steel resulting from contact with molten bronze has been reported in locomotive axles when bearing failure resulted in frictional heating of bronze bearing components to the point where molten bronze contacted the steel axle. This phenomenon has been characterized as liquid metal embrittlement. Three factors are generally required for embrittlement of steel by copper: (1) applied tensile stress, (2) wetting of the steel by molten copper, and (3) heating the steel into the austenite range [5]. In the case
of the DOT cylinder, tensile stress would have been created during hot deformation. Note that the transverse orientation of the leak would be consistent with the direction of tensile stresses created during deformation to form the cylinder. Also, the requirement that a tensile stress be present suggests that the bronze came into contact with the billet prior to forging rather than after forging was complete and stresses were thermally relieved. Wetting by copper would have occurred when the bronze material contacted the steel at forging temperature and the steel would have been in the austenite range at forging temperature. Therefore, the commonly recognized requirements for liquid metal embrittlement were present when the DOT – 3AA cylinder was formed.
6 CONCLUSIONS
The leak on the DOT – 3AA cylinder was caused by liquid metal embrittlement. A localized area of the cylinder was liquid metal embrittled by contact with a copper-rich material, probably a phosphor bronze, while the cylinder was at forging temperature.
This concludes the metallurgical evaluation of a DOT-3AA cylinder with serial no. 441106 with pin hole leak. If you have questions or need additional information please email us at mpareek@https://www.doczj.com/doc/0b1711164.html, or call at 630-577-1930.
Sincerely,
PACKER ENGINEERING, INC.
____________________________ ____________________________
Mridula L Pareek Craig L. Jensen, Ph.D., P.E.
Materials Engineering, Director Engineering
Technologist
7FIGURES
Figure 1: DOT-3AA cylinder as received
Figure 2: Indented marking on the DOT-3AA cylinder
Surface flaw
Figure 3: Surface flaw in the transverse direction on the DOT-3AA cylinder
Figure 5: Radiograph of DOT cylinder with the X-ray source perpendicular to the
flaw. The arrow is pointing to the defect.
Figure 6: Radiograph of DOT cylinder with X-ray source at 45 o to the flaw. The
arrow is pointing to the defect.
Figure 7: Ultrasonic testing of the DOT-3AA cylinder
wave analysis
Figure 9: Ultrasonic Testing - maximum depth of crack measured using shear wave
analysis
Figure 10: Showing location of sectioning of the DOT-3AA cylinder
Figure 11: Shows corrosion on the inside wall of the cylinder
Figure 12: Shows the inside surface of the leak
Figure 13: Shows location at with the samples for tensile testing and chemistry
analysis were sectioned
Figure 14: Shows sections cut for tensile testing and chemistry analysis.
Leak Location
Tensile
Sample Chemistry Sample
Leak Location
Tensile
Sample Chemistry Sample
Figure 15: Sectioning of the cylinder to cut open the leak
Fracture Surface
Figure 16: Seteroscope image of the outer surface of the cylinder section containing
the fracture surface. Magnification 65X
Figure 17: Stereoscope image of the inner surface of the cylinder section containing
the fracture surface. Magnification 65X
Figure 18: Stereoscope image of the cylinder section showing the fracture surface. Magnification 65X
Fracture Surface
Fracture surface
现在完成时讲解和练习 1. 现在完成时的构成: have\has+过去分词(过去分词的构成有规则变化和不规则变化) 2. 现在完成时的四个基本句型 肯定句He has finished the work. 一般疑问句Has he finished the work? 回答Yes ,he has. No, he hasn’t. 否定句He has not finished the work. 特殊疑问句What has he done? 3.现在完成时的用法: A．表示过去发生或已经完成的动作对现在造成的影响或结果，强调对现在造成的影想或结果）。例如：The car has arrived. 车子来了。（结果：车子已在门口） Someone has broken the window.有人把窗户打破了。（结果：窗户仍破着） B. 表示过去已经开始，持续到现在的动作或状态，可以和表示从过去某一时刻延续到现在（包括“现在”在内）的一段时间的状语连用,如for+时间段、since+过去的时间点、疑问词how long等。例如： My uncle has worked at this factory for five years. 我叔叔在这个工厂工作已经五年了。 Mr. Black has lived in China since 2002. 自从2002年Mr. Black 一直住在中国。 How long have you been here? 你来这里多久了？ 4. 在下列情形下用现在完成时 (1)九词语 ①already已经肯定句中或句尾 e.g.: I have already found my pen. = I have found my pen already. ②yet已经否定句和疑问句句尾 e.g.：I have not finished the work yet. Have you bought a computer yet? ③ever曾经句中 e.g.：Have you ever seen pandas? ④never从不句中 e.g.：I have never been to Beijing. ⑤just刚刚句中 e.g.：I have just done my work. ⑥before以前句尾 e.g.：I have never been there before. ⑦so far到目前为止 e.g.：So far he has learnt 200 words. ⑧how long多久 e.g.：How long have you lived here? ⑨how many times多少次 e.g.：How many times has he been to Beijing? (3)三词组 1.have
spend的主语必须是人，常用于以下结构： (1)sb. spend time ／money on sth. 在……上花费时间(金钱)。 (2) sb.spend time ／ money (in) doing sth.花费时间(金钱)做某事。 例：I spent fifty yuan on the coat. = I spent fifty yuan (in) buying the coat. 我花50元买了这件大衣。 He spent three days on the work. = He spend three days (in) doing the work. 我干这项工作用了3天。 (3). spend money for sth. 花钱买 例如： His money was spent for books. 他的钱用来买书了。 cost的主语是物或某种活动，还可以表示"值"，常见用法如下： (1)sth. costs (sb.) ＋金钱,某物花了(某人)多少钱。 例：A new computer costs a lot of money. 买一台新电脑要花一大笔钱。 (2) (doing) sth. costs (sb.) ＋时间,某物(做某事)花了(某人)多少时间。 例：Remembering these new words cost him a lot of time. 他花了大量时间才记住了这些单词。 注意：cost的过去式及过去分词都是cost,并且不能用于被动句。 take后面常跟双宾语，常见用法有以下几种： (1) It takes sb. ＋时间＋to do sth. 做某事花了某人多少时间。 例：It took them three years to build this road. 他们用了三年时间修完了这条路。 (2)doing sth. takes sb. ＋时间,做某事花了某人多少时间。 例：Repairing this car took him the whole afternoon. 他花了一下午修车。 pay的基本用法是： (1) pay (sb.) money for sth. 付钱(给某人)买……。 例：I have to pay them 20 pounds for this room each month. 我每个月要付20英磅的房租。 (2)pay for sth. 付……的钱。 例：I have to pay for the book lost. 我不得不赔丢失的书款。 (3)pay for sb.替某人付钱。 例：Don‘t worry!I'll pay for you. 别担心，我会给你付钱的。 (4)pay sb.付钱给某人。 例: They pay us every month.他们每月给我们报酬。 (5)pay money back 还钱。(6)pay off one's money还清钱。 例：May I borrow 12 yuan from you? I'll pay it back next week. 你能借给我12块钱吗？下周还你。
Lead in 一般过去时导入：一般过去时的概念 一般过去时表示过去某个时间发生的动作或存在的状态。 I lost my pen.(过去时) I have lost my pen.（现在完成时） 过去时一般表示过去所发生的动作或存在的状态。“我把笔丢了”，说话人只是想告诉对方在过去的某一个时间里他的笔丢了，仅此而已。（仅仅是在陈诉过去的一个事实，与现在没有关系） New lesson 一．现在完成时的构成： 助动词have/has(not) +动词过去分词 She has turned on the lights. 肯定式：have/ has+过去分词 否定式：haven’t/hasn’t+过去分词 疑问式：把have/has 提到主语前面 肯定回答：Yes,…have/has 否定回答：No,…..haven’t/hasn’t 二．用法 1.表示过去发生的动作对现在造成的影响或结果. 例如:She has gone. 她走了. She went in the past.(She is not here
now.) I have just cleaned my hands. 我刚洗过手。（“洗手”是发生在过去的动作，对现在造成的结果是“手干净了”） I have closed the door. (The door is close now.) She has turned on the lights. (The lights are on now.) He has written his name on the blackboard. (The name is on the blackboard now.) Mother has cooked the dinner. (We can have dinner now.) You have seen the film. （You know what the film is about.) We have cleaned the classroom. (The classroom is clean now.) 2. 表示动作发生在过去，并且一直延续到现在，甚至还可能继续延续下去。这时常和since所引导的短语或从句或for引导的短语连用(for有时可以省去)。以及so far, by now, these days, in the last/past … years/days…等连用。 I have lived here for over ten years. （表示他现在还在这里居住，并且还有可能继续住下去）比较：I lived here ten years ago.(仅仅说明了他十年前在这里记住过的事实,不代表现在他还住在这里) He has studied here since 2006. 都用How long 提问，例： We have learned English for three years. We have learned English since three years ago.
英语中“花费”的四种用法王朝红的工作室英语花费四种用法 spend的主语通常是人，往往用于以下句型： 1. (sb) spend some money/some time on sth。 2. (sb)spend some money/some time(in)doing sth。 例如： I spent fifty yuan on the coat。 = I spent fifty yuan (in) buying the coat. 我花50元买了这件大衣。 He spent three days on the work. = He spend three days (in) doing the work. 我干这项工作用了3天。 3.spend money for sth. 花钱买……。 例如：His money was spent for books. 他的钱用来买书了。 take常用于“占用、花费”时间，后面常跟双宾语，其主语通常为形式主语“it”或物。句式是： 1. It takes/took sb.some time to do sth 例如：It will take me two days to do the work. 这项工作花了2天时间。 2. Doing sth./Sth.takes sb.some time. 例如： The work will take me two days。这项工作花了2天时间。
Repairing this car took him the whole afternoon. 他花了一下午修车。 It took me three years to draw the beautiful horses。 =Drawing the beautiful horses took me three years。 画这些漂亮的马花费了我3年时间。 pay为“付款、赔偿”之意，主语通常是人，句型 1. sb. pays some money for sth 例如： I paid fifty yuan for the coat。我花50元买了这件大衣。 2. pay (sb。) money for sth. 付钱(给某人)买……。 例如：I have to pay them 20 pounds for this room each month. 我每个月要付20英磅的房租。 3. pay money back 还钱。 例如：May I borrow 12 yuan from you? I'll pay it back next week. 你能借给我12块钱吗?下周还你。 4. pay off one's money 还清钱。 cost的主语是物或某种活动，还可以表示“值”。句型 1. sth. costs (sb。) +money, 某物花了(某人)多少钱。
枷Cd)一点，一些 扒；Olooksabitlarge．看起来有点大。 l“HeknowsabitOfGermam他懂点德语。 轴蛔chof一束；一捆 He gave his girlfriend a bunch Of roses 9s a birthday gift． 他送女友一束玫瑰作为生日礼物。 la'0wdOf一群；许多 A crowd Of children with bouquets 1n their hands rushed Over tO the foreign guests，一群孩尸手持鲜花向外国客人咆去． afew几个；一些 HewiIIbe here in a Jew days．他过几天就来。 ．goed／greatmany很多：许多 Mr Liu rang her up a good many times．刘先生多次打电话给她． ．good／greatdeal(O，)大量；很多 I'm afraid I've gtven you s good deal“trouble． 我恐怕给你添了很多麻烦。 After taking the medicine he i'nOW a great deal better． 服药后，他现在觉得好多了。 alot(d)许多；大量 The students learned a lot from the teacher． 学生们从老师那里学到了许多知识。 He borrowed s lot Of books from the old胴n． 他从那位老人那里借丁很多书． alargeamotmtOf许多(按不可数名词) A 1arge amountOfmoney has been wasted．大量的金钱被浪费掉丁。 9(1arge)quantityOf许多(接可数或不可数名词) Heateo smallquantityO{rice．他吃了少量的米饭。 anmberOf一壁：若干 Quite a number 9f students inour department are from the north． 我们系有许多学生来刨[方。 aseriesOf一系列的 A series Of reports will be given On the war． 关于这场战争将有一系列的报道。 asetOf一组，，一套 The factory bought a set Of equtpment from abroad． 这家工厂从国外买厂一套设备。 ovametyOt多样，种种，多种类 The shoppingcentresellsavartetyOrgoods．这个购物中心出售许多种商品。 ~,all首要的；最重要的·： ．That心what IP陀f畸above，11．那是我最喜欢的东西． 删lqto根据；依照 According tO theweather reagort,出CrC will加rain this afternoolL
LESSON EIGHT 四种完成时态 主系表 现在：You are rich. 过去：You were rich. 将来：You will be rich. 过去将来：You would be rich. There be 现在：There is a book on the desk . 过去：There was a book on the desk. 将来：There will be a book on the desk. 过去将来：There would be a book on the desk.主谓宾状 现在：You study English in the school. 过去时：You studied English in the school. 将来时: You will study English in the school. You are going to study English. You are to study English. are about to study English would study English in the scho You were going to study English. You were to study English. You were about to study English. You are studying English. You were studying English. You will be studying English. You woud be studying English.
“四个花费”讲解及对应中考练习 spend，cost，take, pay spend，cost，take和pay的区别是历年考试的必考内容之一，虽然它们都可以表示"花费"，但用法却不尽相同，讲解如下： spend的主语必须是人，常用于以下结构： (1) spend time ／money on sth. 在……上花费时间(金钱)。 例：I spent two hours on this maths problem. 这道数学题花了我两个小时。 (2) spend time ／money (in) doing sth. 花费时间(金钱)做某事。 例：They spent two years (in) building this bridge. 造这座桥花了他们两年时间。 (3)spend money for sth. 花钱买……。 例：His money was spent for books. 他的钱用来买书了。 cost的主语是物或某种活动，还可以表示"值"，常见用法如下： (1)sth. costs (sb.) ＋金钱,某物花了(某人)多少钱。 例：A new computer costs a lot of money. 买一台新电脑要花一大笔钱。 (2) (doing) sth. costs (sb.) ＋时间,某物(做某事)花了(某人)多少时间。 例：Remembering these new words cost him a lot of time. 他花了大量时间才记住了这些单词。 注意：cost的过去式及过去分词都是cost,并且不能用于被动句。 take后面常跟双宾语，常见用法有以下几种： (1) It takes sb. ＋时间＋to do sth. 做某事花了某人多少时间。 例：It took them three years to build this road. 他们用了三年时间修完了这条路。 (2)doing sth. takes sb. ＋时间,做某事花了某人多少时间。 例：Repairing this car took him the whole afternoon. 他花了一下午修车。 pay的基本用法是： (1) pay (sb.) money for sth. 付钱(给某人)买……。 例：I have to pay them 20 pounds for this room each month. 我每个月要付20英磅的房租。 (2)pay for sth. 付……的钱。 例：I have to pay for the book lost. 我不得不赔丢失的书款。 (3)pay for sb. 替某人付钱。 例：Don‘t worry!I'll pay for you. 别担心，我会给你付钱的。 (4)pay sb. 付钱给某人。 例: They pay us every month.他们每月给我们报酬。 (5)pay money back 还钱。 例：May I borrow 12 yuan from you? I'll pay it back next week. 你能借给我12块钱吗？下周还你。 (6)pay off one's money还清钱。 【真题对应练习】 1.（广州某校2015期中）--- How much does your new bike ___________ ?
初二英语上册语法的复习方法与详细解释 初二英语上册语法的复习方法与详细解释 38)help用法举例 help既可以作名词，也可以作动词。 1.help作名词，意为"帮助"。如： Heneedssomehelp.他需要一些帮助。 2.help作动词，也是"帮助"的意思。如： Canyouhelpme?你能帮帮我吗？ 3.help的结构： helpsb(to)dosth帮助某人做某事 =helpsbwithsth帮助某人做某事 如：Theywanttohelptheboycarrytheheavybox. =Theywanttohelptheboywiththeheavybox. 他们想要帮助那位男孩搬那个重箱子。 20)关于like的用法 like可以作动词，也可以作介词。 Doyoulikethecolor?你喜爱这种颜色吗？ like后可接不定式（liketodosth），也可接动词的-ing分词（likedoingsth），有时意思不尽相同。如： Shelikeseatingapples.她喜爱吃苹果。（习惯） Shelikestoeatanapple.她喜爱吃一粒苹果。（平常不喜欢吃）
like与would连用，后接不定式，表示愿望或客气的请求。如： Wouldyoulikeacupoftea?您愿意喝杯茶吗？ "喜欢某人做某事"可以用结构"likesbtodosth/doingsth"。如：Theyalllikemetosing/singingEnglishsongs. 他们都喜欢我唱英文歌。 2、like作介词，可译成"像......"。如： Sheisfriendlytouslikeamother.她对我们友好，就像母亲一样。 Itlookslikeanorange.它看起来像个桔子。 3、区分以下句子： A.Whatdoeshelooklike?他长相如何？(指一个人的外貌特征) B.Whatishelike?他人怎么样？(指人的性格特点) C.TheboylikePeterisoverthere.(句指外貌相似) D.AboylikePetercan'tdoit.(指性格相似) 19)alittle,afew与abit(of)alittle,afew与abit(of)都有" 一些、少量"的意义。他们的区别: 1.alittle意为"一些、少量"，后接不可数名词。如： Thereisalittlewaterinthebottle.瓶子里有一点水。 还可以接形容词。如： Heisalittleshy.他有些害羞。 2.afew意为"一些、少数"，后接复数的可数名词。如： Thereareafewpeopleintheroom.房间里有一些人。 3.abit意为"一点儿"，后接形容词。如： It'sabitcold.有点冷。
四种花费和四种提供的 用法 公司内部编号：（GOOD-TMMT-MMUT-UUPTY-UUYY-DTTI-
英语中“花费”的四种用法王朝红的工作室英语花费四种用法 spend的主语通常是人，往往用于以下句型： 1. (sb) spend some money/some time on sth。 2. (sb)spend some money/some time(in)doing sth。 例如： I spent fifty yuan on the coat。 = I spent fifty yuan (in) buying the coat. 我花50元买了这件大衣。 He spent three days on the work. = He spend three days (in) doing the work. 我干这项工作用了3天。 3.spend money for sth. 花钱买……。 例如：His money was spent for books. 他的钱用来买书了。 take常用于“占用、花费”时间，后面常跟双宾语，其主语通常为形式主语“it”或物。句式是： 1. It takes/took sb.some time to do sth
例如：It will take me two days to do the work. 这项工作花 了2天时间。 2. Doing sth./Sth.takes sb.some time. 例如： The work will take me two days。这项工作花了2天时间。 Repairing this car took him the whole afternoon. 他花了一下午修车。 It took me three years to draw the beautiful horses。 =Drawing the beautiful horses took me three years。 画这些漂亮的马花费了我3年时间。 pay为“付款、赔偿”之意，主语通常是人，句型 1. sb. pays some money for sth 例如： I paid fifty yuan for the coat。我花50元买了这件大衣。 2. pay (sb。) money for sth. 付钱(给某人)买……。 例如：I have to pay them 20 pounds for this room each month.我每个月要付20英磅的房租。
Take\spend\pay\cost表示花费的时候用法1、It takes sb some time to do sth. 该句型只表示花费时间，it是形式主语，真正的主语是动词不定式。sb是宾格形式，some time 是一段时间。 Eg： a.It took the boys two weeks to plant the trees last spring. b.It takes me ten minutes to walk to school every day. c.It will take us about 30 minutes to finish listening the story. 2. Sb spends some time/money (in) doing sth. Sb spends some time/money on sth. 该句型可表示花费时间，也可以表示花费金钱。主语必定是人，做某事可以用动词表示，也可用名词表示。 d.We spent the whole day going hiking in Mount Tai last summer. e.Did you spend ten yuan on the pen? f.All the boys spent about five minutes
remembering the ten English words. 除此之外，还有pay和cost也可以表示花费金钱。 Pay 常用for连用，构成pay for 意思是赔尝、付款。主语必须是人。 I paid for the book yesterday. 昨天我买了这本书。 I paid ten yuan for the book yesterday. 昨天我花了十元钱买了这本书。 You should pay for the book if you lose it. 如果你丢了这本书，你就应该赔偿。 Cost 表示值多少钱，也表示花费。 The magazine costs twenty yuan. The bicycle cost me eight hundred and fifty yuan.
Unit 4 Astronomy: the science of stars教案 Unit 4 Astronomy: the science of stars教案Teachingaims: .Talkaboutthescienceofstars 2.PractisegivinginstructionsTeachingdifficulties:1. Learntousenounclausesasthesubject 2.Learntowriteanessaytoshowyourproblemsandthewaytoo vercomethem. 3.Vocabulary:astronomy,atmosphere,violent,explode,s urface,disappointed,gradually,cheer,mass,harmful,pr esence,intime,prevent…from…dependon,nowthat,getthehangof,breakout
Teachingprocedures:ThefirstperiodIntensivereading StepⅠPresentation T:Hello,everyone!TodaywewillcometoUnit4,Astronomy.B eforethatIhaveaquestion:wheredowecomefrom?orwecansa y:whoareourancestors? S1:monkeys! S2:BeijingRenwholivedmanyyearsago. S3:dinosaurs … T:Verygood!Doyouknowwhatitwaslikebeforelifeappeared onearth? S4:Fullofwater… Bs:Idon’tknow. T:Doyouwanttogetmoreinformation? Ss:yes,wedo. T:Todaywewilllearnsomethingabouthowlifebeganonearth .Turntopage25.Let’scometowarmingupfirst. StepⅡwarmingup .Readthethreequestions,whilethestudentslistenan
四种花费和四种提供的 用法 Revised as of 23 November 2020
英语中“花费”的四种用法王朝红的工作室英语花费四种用法 spend的主语通常是人，往往用于以下句型： 1. (sb) spend some money/some time on sth。 2. (sb)spend some money/some time(in)doing sth。 例如： I spent fifty yuan on the coat。 = I spent fifty yuan (in) buying the coat. 我花50元买了这件大衣。 He spent three days on the work. = He spend three days (in) doing the work. 我干这项工作用了3天。 money for sth. 花钱买……。 例如：His money was spent for books. 他的钱用来买书了。 take常用于“占用、花费”时间，后面常跟双宾语，其主语通常为形式主语“it”或物。句式是： 1. It takes/took time to do sth
例如：It will take me two days to do the work.这项工作花了2天时间。 2. Doing sth./ time. 例如： The work will take me two days。这项工作花了2天时间。 Repairing this car took him the whole afternoon. 他花了一下午修车。 It took me three years to draw the beautiful horses。 =Drawing the beautiful horses took me three years。 画这些漂亮的马花费了我3年时间。 pay为“付款、赔偿”之意，主语通常是人，句型 1. sb. pays some money for sth 例如： I paid fifty yuan for the coat。我花50元买了这件大衣。 2. pay (sb。) money for sth. 付钱(给某人)买……。 例如：I have to pay them 20 pounds for this room each month. 我每个月要付20英磅的房租。 3. pay money back 还钱。
精心整理英语中的量词 英语中的量词 我们都知道汉语有大量的量词,其实英语也有不少量词,区别在于:(1)英语中的量词不是一个单独的词类而是名词下的一个小类;(2)英语中的量词不能用来表示单数可数名词的量;(3)英语中的量词通常被称为单位词或其他一些名称. 由于上述原因,英语中的量词没有受到足够多的重视,学生往往只知道很少几个量词,而且还经常因为不能确定它们的搭配而烦恼.为了方便同学们学习和使用,我们把英语中的量词分为以下几个类别并列举了一些常见的量词及搭配: 1. /一张纸/ /一2. combacombofbananas一串香蕉 dropadropofrain/blood一滴雨/一滴血 earanearofcorn/wheat一棒玉米/一穗麦子 flightaflightofstairs/arrows/sparrows一段楼梯/一阵箭雨/一群麻雀 flockaflockofworkmen/criminals/boys一群工人/一伙罪犯/一群男孩
headaheadofcabbage/cauliflower/sheep一头卷心菜/一块花菜/一头羊lumpalumpofsugar/coal/clay一块糖/一块煤/一块土spiralaspiralofmosquitoincense一盘蚊香 sliceasliceofmeat/bread/beef一片肉/一片面包/一块牛肉swarmaswarmofbees一群蜜蜂 bevyabevyofbeauties/girls/ladies一群美人/一群女孩/一群女士 3. apacketofcigarette一包烟 4.表示行为动态的量词: fitafitoflaughter一阵笑声 pealapealofthunder一阵雷声 flashaflashoflight一道闪电
现在完成时 一．构成 助动词have/has + 过去分词 例:肯定句I have worked. He has worked. 否定句I have not (haven't ) worked. He has not (hasn't )worked . 疑问句Have you worked ? Has he worked ? 回答Y es，I have. / No , I haven't . Y es, he has./ No, he hasn't. 二．功能及意义 1.表示一个动作发生在过去，对现在仍有影响，但没有具体的过去时间修饰。常由下列副词修饰：ever曾经，never从不，already已经，yet还（未），（yet 只用在否定句和疑问句中），just刚刚，recently，lately近来，so far 迄今为止= until now, up to now，before 以前 例：Have you ever been to the Great Wall? 你曾经去过长城吗？ I have never heard of such a man.我从没有听说过那个人。 We have just had lunch 我们刚刚吃过午饭 I have already returned your money.我已经把钱还给你了。 I haven't found my book yet. （否）我还没有找到笔记本 Have you done your homework yet?（疑）你做作业了吗？ Have you heard from him recently ? 你最近收到他的来信了吗？ So far, no one has made any mistakes yet.迄今为止还没有人犯错误 I have never traveled by plane before .我以前从来没有乘飞机旅行过 2 表示一个动作发生在过去，一直持续到现在刚刚结束或者仍在继续。常常与下列时间状语连用： →for + 一段时间 I have learned English for 8 years →since + 过去的一个时间点 I have learned English since 2001 →since + 一段时间+ ago I have learned English since 8 years ago →since + 时态为一般过去时的时间状语从句 I have learned English since I was 5 years old → in the past/last +时间段 We have had two English exams in the past two months近两个月来我们进行了2次英语考试 Great changes have taken place in my hometown in the past ten years 近十年来我的家乡发生了巨大的变化。 三延续性动词与短暂性动词的用法
英语牛津译林九上unit4：经典学案（2）+练习题及解析 （readingi） 注意事项： 1. 答题前，考生先将自己的姓名、准考证号填写清楚，将条形码准确粘贴在考生信息条形码粘贴区。2．选择题必须使用2B铅笔填涂；非选择题必须使用0.5毫米黑色字迹的签字笔书写，字体工整、笔迹清楚。 3．请按照题号顺序在各题目的答题区域内作答，超出答题区域书写的答案无效；在草稿纸、试题卷上答题无效。 4．保持卡面清洁，不要折叠，不要弄破、弄皱，不准使用涂改液、修正带、刮纸刀。 9AUNIT4READINGI 【学习目标】 1、进一步认识和掌握与电视相关的词汇及语段。 2、学会不同电视节目的特征及描述用语。 【课前准备】 1、对各种不同的电视节目有初步的了解。 2、提高根据所阅读文章判断正误的能力。 【学习内容】 词组：1ANUMBEROF2THECOMINGWORLDCUP3BECOVEREDLIVE 4VOTEFOR5SENDTEXTMESSAGETO 句型：IFYOUARENOTAFOOTBALLFAN，YOUMIGHTFINDTHISWEEK'SPROGRAMMERABITBORING ASYOUAREWATCHINGTHESHOW，WRITEDOWNYOURANSWERSANDSENDTEXTMESSAGESTO1396 【课堂学习】 【一】语言知识〔词汇理解〕 GIVEANOPINIONFORORAGAINSTSB.ORSTH.VOTEDIRECTSTH.BEPRESENTED TOBEPRESENTATANEVENTAWARDATTENDMODERN，FASHOINABLE APERSONWHODIRECTSAFILMP－TO－DATEPRESENTATIONPRIZE WEEKLY是形容词，意为“每周的，一周的”，它是由名词＋LY构成的。 类似的词还有：FRIENDLY〔友好的〕MOTHERLY（慈母般的）MONTHLY（每月的）ABIT意为“一点儿，稍微，少许”，可以用来修饰形容词或副词。 如果用来修饰不可数名词，后面要加上介词OF，即ABITOF＋不可数名词。 E.G.THAT'SABITTOOEXPENSIVE LETMEGIVEYOUABITOFADVICE. ANUMBEROF意为“大量的，许多”，NUMBER前可用LARGE／GREAT／BIG等词修饰，OF后接复数名词，所构成的短语作主语时，谓语动词常用复数形式。 THENUMBEROF意为“…..的数量，…..的数目”。后接复数名词，所构成的短语作主语时，谓语动词常用单数形式。 E.G.ANUMBEROFPEOPLEARESTANDINGOUTSIDETHEOFFICE. THENUMBEROFTHESTUDENTSINOURSCHOOLISMORETHAN1000 【能力训练】 根据课文内容判断正误 1.SOMEPEOPLEMAYFINDTHISWEEK'SSPORTSWORLDABITBORING. 2.THEWORLDCUPHASBEENHELDALREADY.
现在完成时态 1. 用法：①表示过去发生的动作对现在造成的影响和结果，强调结果.常用的时间状语有many times，just，yet，ever，never，just，already，so far, by now 等。②表示动作或者状态在过去已经开始，持续到现在，也许还将持续下去。用于延续性动词，常常与so far、for或者since短语连用。since + 时间点/从句，for + 时间段，如for two months等。 2. 现在完成时的构成have has+过去分词 3. 现在完成时的四个基本句型 肯定句He has finished the work. 一般疑问句Has he finished the work? 否定句He has not finished the work. 两回答Yes ,he has. No, he hasn’t. 特殊疑问句What has he done? 4. 在下列情形下用现在完成时 1九词语 ①already 已经肯定句中或句尾: I have already found my pen. = I have found my pen already. ②yet已经否定句和疑问句句尾例：I have not finished the work yet. Have you bought a computer yet? ③ever曾经句中例：Have you ever seen pandas? ④never从不句中例：I have never been to Beijing. ⑤just刚刚句中例：I have just done my work. ⑥before以前句尾例：I have never been there before. ⑦so far到目前为止例：So far he has learnt 200 words. ⑧how long多久例：How long have you lived here? ⑨how many times多少次例：How many times has he been to Beijing? 2两词组 have