58_02.Intermediate Weld Discontinuities _compressed.pdf

cem WSS Study Guide WD2.1 rhHN nh Intermediate Weld Discontinuities Hydrogen-induced cold cracking (HICC) can occur in the weld metal or the heat-affected zone and in any orientation with respect to the weld axis. Commonly observed positions of hydrogen-induced cold cracks in groove and fillet w...

cem WSS Study Guide WD2.1 rhHN nh Intermediate Weld Discontinuities Hydrogen-induced cold cracking (HICC) can occur in the weld metal or the heat-affected zone and in any orientation with respect to the weld axis. Commonly observed positions of hydrogen-induced cold cracks in groove and fillet welds are shown in Figures 45 and 46. Crater crack Transverse crack Longitudinal crack Transverse crack. HAZ Toe crack HAZ Fusion line cracking Underbead Root crack G45] crack HAZ Location oƒ hydrogen-induced cold cracks in groove welds x Root crack Toe crack Underbead crack mm Location oƒ hydrogen-induced cold cracks in fillet welds WSS Study Guide WD2.1 CWBï acorn An iniriauve of the cwbgroup Intermediate Weld Discontinuities Transverse cracks in the weld metal may extend into the heat-affected zone of the parent plate and beyond. Heat-affected zone cracks are usually longitudinal and most often occur at the root or the toes of the welds. Under some conditions longitudinal cracks may be very long, sometimes running the entire length of the weld. Cold cracking may also manifest itself as fine micro-cracks, difficult to detect by normal inspection and nondestructive test methods. The presence of micro-cracks may be symptomatic of a more serious condition, such as a high hydrogen level, that could lead to more serious cracking. Cracks may be detected by visual examination if the cracks are open to the surface and large enough, or by nondestructive methods suitable for detecting surface discontinuities. Subsurface cracks may be detected by nondestructive methods capable of detecting subsurface discontinuities. Due to their geometry, cracks are always considered a defect and must be repaired. The repair must ensure that the crack is completely removed, usually by excavating the weld or base metal to remove the crack. Then nondestructive testing is carried out agaïn to ensure that the crack is completely removed. Re-welding is performed following repair procedures and nondestructive testing is tựypically carried out again to ensure that new cracks did not form from the repair welding. Nondestructive examination shall be delayed as long as practicable and preferably not less than 48 h after completion of the welds. 4. Design-Related Discontinuities Sometimes discontinuities arise from problems within the design of the structural details or in choosing the wrong type of weld joint for a given application. lf the problem is attributed to the design of the weld joint and then welding is performed, the resulting discontinuity or defect is considered design-related. Page 60 9 2015 CWB Group Industry Services WSS dải Gủide WD2.1 Intermediate Weld Discontinuities Specific mechanical and chemical properties are required of all welds made in any given weldment. These requirements will depend on the codes or specifications involved and departure from these specified requirements is considered a defect. Properties are generally determined with specially prepared test plates but may be made on sample weldments taken from production procedure qualifications. Where test plates are used, the inspector should see that specified welding procedures are followed, otherwise the results obtained will not necessarily indicate the actual properties of the weldments. Mechanical properties that may be defective ïf procedures are not followed are: tensile strength, yield strength, ductility, hardness and impact. Chemical properties may be deficient because of incorrect weld metal composition or welding procedure and both of these may result in lack of corrosion resistance. Not all of these defects are due to improper welding conditions, since many such difficulties can be caused by the base metal. Properties of the base metal that may not meet the requirements are chemical composition, internal conditions (laminations and stringers), surface conditions (mill scale, grease, paint, oil, etc.) and mechanical properties. In the case repair will prepared. weldment Page 61 | Copyright © 2015 CWB Group Industry Services | of defective properties of usually involve the welded lf there are problems with may not be acceptable for weld metal and/or base metal, joint being removed and a new joint the base metal, the entire use. WSS Studv Guide WD2.1 cwbgroup Intermediate Weld Discontinuities Guides and Exam Exercise To obtain maximum benefit from this study guide we suggest that you follow this guide and complete the exercise as indicated. It is important that you work through the text methodically, studying each section thoroughly before moving on. The exercises are designed to give you an indication of whether vou have learned the material and can move on or whether you need to go back and study the section again. Do the exercises honestly. They will not help vou unless you take them seriously. lf you get a question wrong, go back through the text until you understand where you have gone wrong and know the correct answer. The length of time required to complete the module will vary from student to student. Find you own pace. Do not rush. Remember you are trying to teach vourself something, not win a race. Some people like to underline sections when they read a text. We suggest that you use caution ïf vou do this. What you think is important first time you read ït may be different after reading it three times. We suggest you read a section three times thoroughly before highlighting anvthing. The exam exercise is designed to give you an indication of whether you are ready to take the closed-book exams. The exercise questions are of a similar standard to the official exams. Do not take the exam until vou feel you are ready. You may wish to study several modules before taking the exams on each. lf you have any difficulties with this module do not hesitate to ask for help. Vou may contact us at 1-800-844-6790, fax us at 905-542-1318 or email us [email protected]. Page 62 Copyright © 2015 CWB Group Industry WSS I ˆ Guide WD2.1 nh Intermediate Weld Discontinuities Carefully read Sections 1 and 2.1 and answer the following questions. What is the term for an interruption of the typical structure Of a material? (a) (b) undercut defect (c) (d) discontinuity rejectable From the following list, check off those iterns that are dimensional errors related to preparation and fit-up for welding. (a) incorrect root openings (b) insufficient leg (c) (d) (e) (Đ) Overlap incorrect root face incorrect bevel angles insufficient throat In CSA Standard W59, a groove angle and AWS D1.1, a groove angle specified on a drawing as 60° should be between: Page 63 Copyright © 2015 CWBE Group Industry Services (a) 45° and 60° (b) (c) (d) 55° and 70° 55° and 65° 60° and 70° CWBï acorn. WSS Study Guide WD2.1 An Initiativeof the cwbgroup Intermediate Weld Discontinuities Carefully read Sections 2.2 to 2.16 and answer the following questions. 1. One of the typical causes of overlap is contamination of the Joint preparation. Name three contaminants listed in this study guide. 2. Complete the following sentence: The term convexity normally refers to the profile of a weld. 3. 4. A groove weld is determined to have undercut along the toes of the weld in excess of what is permitted by the applicable standard. The undercut may be corrected by: (a) grinding away the parent material until the undercut is removed and a smooth contour ïs formed between the base material and the weld. (b) clean and deposit an additional pass directly over the undercut. (c) grinding the undercut regions to provide a U groove profile and depositing weld passes to fill in the U groove. (d) gouging to remove the undercut regions, followed by grinding. Concavity of a fillet weld is defined as: (a) the minimum distance from the face of a concave fillet weld perpendicular to a line joining the weld toes. the maximum distance from the face of a concave fillet weld perpendicular to a line joining the weld toes. the over-welding of a illet weld. dished out regions or voids resulting from trapped gas between the weld and slag system during the solidification of welds made with the SAW process. 5, True or False? Careless backgouging so that the groove is displaced from the weld root can lead to out-of-line weld beads. Page 64 Copyright © 2015 CWB Group Industry Services WSS HỆ Guide WD2.1 CWBï aporn ® H cwbgroup Intermediate Weld Discontinuities True or False? All of the following are fusion discontinuities in a complete joint penetration groove weld. Incomplete fusion (insert) Incomplete sidewall fusion Incomplete root fusion Underbead non-fusion Incomplete joint penetration The term describes a condition at the root of a groove weld where the weld metal does not extend through the Joint thickness: (a) (b) (c) (d) incomplete fusion undercut complete joint penetration incomplete joint penetration Which of the following is NOT considered a process or procedurerelated weld discontinuity? (a) (b) lamellar tearing distortion (c) solidification cracking (d) undercut r WSS Study Guide WD2.1 Intermediate Weld Discontinuities Carefully read Sections 3 to 4 and answer the following questions. 1. Porosity may occur: (a) (b) (c) (d) open in the below open to the surface of the weld only. heat-affected zone. the surface of the weld only. to the surface and/or below the surface of the weld. 2. Name three probable basic causes of porositv. 3. Surface contaminants such as oil, grease, paint and oxides can result in (a) (b) 4. Page 66 Copyright © 2015 CWB Group Industry Services distortion pOrosity (c) insufficient throat (d) excessive reinforcement Solidification cracks are: (a) {b) (c) (d) @ if they are not removed prior to welding. transverse in direction. Open only to the weld surface. longitudinal in direction. Tormed at the weld root. WSS Study Guide WD2.1 cwbgroup Intermediate Weld Discontinuities 5B True or False? Hydrogen-induced cold cracks may occur in the weld metal or heat-affected zone. 6. Complete the following sentence: As the name implies, cold cracking forms at low temperatures, generally below Page 67 Copyright © 2015 CWB Group Indust °C. @ WSS Study Guide WD2.1 Intermediate Weld Discontinuities = Guide1 b 2. () (a), (d), (e) (b) 8 xÐm..a. S©m x = Guide2 Oil, paint, rust, mill scale fillet (b) (b) True False (d) (a) Guide3 (d) @ Page 68 Copyright © 2015 CWB Group Industry Services 2. Moisture, chemistry and structure of parent material, surface impurities and contaminants, faulty electrodes, fuxes or shielding gases, slag, operator techniques. 3 (b) 4. (c) 5. True 6. 150 °C (302 °F) li. WSS Studyi Guide WD2.1 eo. cwbgroup Intermediate Weld Discontinuities This test is designed to determine whether you are ready to attempt the Exam formal examination. Exercise Complete the answer sheet and compare the results with the answer key. lf you score less than 70%, we suggest you re-study the material. 1. Which of the following is a class of weld discontinuity? (a) (b) (c) (d) 2. 3. Which of the following weld discontinuities may occur due to insufficient root opening? (a) (b) (c) Excessive melt-through Underfill Porosity (d) Incomplete joint penetration Proper material selection and use may be verified by: (a) (b) (c) (d) 4. 3 2015 CWB Group Industry Services Design-related Environmental-related Dynamic-related Production-related mill test certificates. looking at the material. hardness testing. bend testing. Overlap of a filiet weld: (a) affects the length of the weld. (b) (c) affects painting of the completed weldment. increases the amount of filler metal consumed. (d) affects the strength of the joint. 9 WSS Study Guide WD2.1 Intermediate Weld Discontinuities The term convexity normally refers to the profile of a: (a) fillet weld. (b) groove weld. (c) (d) weldment. Joint preparation. Which of the following typically causes excessive weld reinforcement? (a) (b) (c) (d) depositing too few passes improper weld pass sequencing improper welding flux wrong choice of shielding gas Porosity may occur: (a) Open to the surface of the weld only. (b) (c) (d) in the heat-affected zone only. below the surface of the weld only. open to the surface and/or below the surface of the weld. Surface contaminants such as oil, grease, paint and oxides can result in Ïf they are not removed prior to welding. (a) distortion (b) porosity (c) undercut (d) insufficient groove angle Where do transverse cracks occur? (a) (b) (c) (d) 10. Weld Weld Base Weld metal and base metal metal only metal only craters What may cause cracks or microfissures due to rapid cooling (quench effect) of the base metal? (a) (b) (c) (d) Page 70 Copyright © 2015 CWB Group Industry Services Spatter Grinding Arc strikes Arc flash | Ễ WSS Study|Guide WD2.1 Intermediate Weld Discontinuities Answer Sh † ee ! : 2E Em ; Complete the answer sheet and compare the results with the answer key. lf you score less than 70%, we suggest you re-study the material. Please circle only ONE letter corresponding to the answer you think is most correct. 1 a b c d L 2 a b G d 8 3 a b lc d e 4 a b c d g 5 a b c d Gì 8 a b G d g 7 a b c d e 8 a b c d e 9 a b [> d ti 10 a b S d e The answer sheet below is provided for your use in the event that you wish to retest vourself. Page 71 Copyright © 2015 1 a b e d e 2 a b c d g 3 a b c d e 4 a b c d e 5 a b hà d e 6 a b c d 6 r a b c d e 8 a b C d e 9 a b G d e 10 a b C d C @ WSS Study Guide WD2.1 Intermediate Weld Discontinuities Compare your answer sheet to this key. ® Answer Key LỤ = [œ] to œm ¬I ØơƠ ƠØ †+ 1o MS Answers @® Page 72 Copy: !Ø 2015 CWB Group Industry Services WSS StudyGuide WD2.1 Intermediate Weld Discontinuities WSS Revision Log Revision # Revision Date Revision Detalils Update 1.2 2018-06-05 In Welding Supervisor Steel books, the CWB logos have been updated to the new ones, some illustrations and text have been revised as follows: JS2.1 Intermediate Welding Symbols $ $ Page 53, Figure 41 was revised Page 54, Figure 43 was revised WD2.1 Intermediate Weld Discontinuities $ Page 33, Figure 26 was revised $ Page 68, Answer to #8 was changed to (a) Welding Supervisor Steel Course Background Miaterial $ $ Page 20, 29 and 41 Figures were revised Page 50 was deleted as it was the same as page 48 Wa47.1 Study Guide, Workshop and Procedure Guide WXE1.1 $ CSA Standard W47.1-09 (reaffirmed 2014) Page 57, the answer to question 34 was changed to “b” WXE1.2 CSA Standard W47.1-09 (reaffirmed 2014) $ Page 2, three more Annexes were added WXE1.3 CSA Standard W47.1-09 (reaffirmed 2014) $ Page5,83,9,11, 13, ,22, 25, 29, 40 and 49 Figures were revised $ Page 20, minor text revision $ Page 31, 33, 35, 58 and 59 Figures were revised W59 Study Guide & Workshop WXE2.1 CSA Standard W59-13 $ $ $ Page 73 Copyright © Page 19 and 33 minor text additions Question #56, in Section 3 has been changed The answer to Question #56, in Section 4 has been changed to “a” ø WSS Study Guide WD2.1 Intermediate Weld Discontinuities WSS Revision Log Revision # Revision Date Revision Details Update 1.3 2018-09-4 In Welding Supervisor Steel books, some illustrations and text have been revised as follows: JS2.1 Intermediate Welding Symbols $ Page 42, Figure 36; Page 46, Figure 40 and Figure on page 49 were revised WC2.1 Intermediate Quality Control and Inspection Miethods $ Page 34, Figure 27 and Page 35 Figure 26 were revised WD2.1 Intermediate Weld Discontinuities $ Table 2, Figure 23, Figure 25 and Figure 32 were revised. Welding Supervisor Steel Course Background Material $ $ Figures on pages 20, 38 and 40 were revised. Page 40, minor text revision. W47.1 Study Guide, Workshop and Procedure Guide WXE1.3 CSA Standard W47.1-09 (reaffirmed 2014) $ Figures on pages 27, 31 and 34 were revised. W59-18 Study Guide & Workshop WXE2.1 CSA Standard W59-18 - Study Guide $ Page 19, 20, 28, minor text revisions. Page 30, answer 79f was revised WXE2.1 CSA Standard W59-18 - Workshop $ $ Page 74 Copyright © 2015 CWB Group Industry Services Updated page number references to match W59-18 new Standard. Page 20, 22, 27 and 30, minor text revisions.