1、WELDING INSPECTION TECHNOLOGY FIFTH EDITION2008 Published by American Welding Society Education Department Education Servicesii WELDING INSPECTION TECHNOLOGY DISCLAIMER The American Welding Society, Inc. assumes no responsibility for the information contained in this publication. An independent, sub
2、stantiating investigation should be made prior to reliance on or use of such information. International Standard Book Number: 978-0-87171-579-1 American Welding Society 550 N.W. LeJeune Road, Miami, FL 33126 2008 by American Welding SocietyAll rights reserved Printed in the United States of America
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5、ernet: .WELDING INSPECTION TECHNOLOGY iii Table of Contents Chapter Title Page 1 Welding Inspection and Certification 1-1 2 Safe Practices for Welding Inspectors 2-1 3 Metal Joining and Cutting Processes 3-1 4 Weld Joint Geometry and Welding Symbols 4-1 5 Documents Governing Welding Inspection and Q
6、ualification 5-1 6 Metal Properties and Destructive Testing 6-1 7 Metric Practice for Welding Inspection 7-1 8 Welding Metallurgy for the Welding Inspector 8-1 9 Weld and Base Metal Discontinuities 9-1 10 Visual Inspection and Other NDE Methods and Symbols 10-11-1 CHAPTER 1 Welding Inspection and Ce
7、rtification Contents Introduction 1-20 Who is the Welding Inspector? .1-30 Important Qualities of the Welding Inspector.1-30 Ethical Requirements for the Welding Inspector1-60 The Welding Inspector as a Communicator 1-60 Personnel Certification Programs.1-80 Key Terms and Definitions1-111-2 CHAPTER
8、1WELDING INSPECTION AND CERTIFICATION WELDING INSPECTION TECHNOLOGY Introduction In todays world there is increasing emphasis placed on the need for quality, and weld quality is an important part of the overall quality effort. This concern for product quality is due to several factors, including eco
9、nomics, safety, government regulations, global competition, and the use of less conservative designs. While not singularly responsible for the attainment of weld quality, the weld- ing inspector plays a large role in any successful welding quality control program. In reality, many people partici- pa
10、te in the creation of a quality welded product. How- ever, the welding inspector is one of the “front line” individuals who must check to see if all of the required manufacturing steps have been completed properly. To do this job effectively, the welding inspector must have a wide range of knowledge
11、 and skills, because it in- volves more than simply looking at welds. Consequently, this course is specifically designed to provide both expe- rienced and novice welding inspectors a basic back- ground in the more critical job aspects. This does not imply, however, that each welding inspector will u
12、se all of this information while working for a particular com- pany. Nor does it mean that the material presented will include all of the information for every welding inspec- tors situation. Selection of these various topics is based on the general knowledge desirable for an individual to do genera
13、l welding inspection. The important thing to realize is that effective welding inspection involves much more than just looking at fin- ished welds. Section 4 of AWS QC1, Standard for AWS Certification of Welding Inspectors, outlines the various functions of the welding inspectors. You should become
14、familiar with these various responsibilities because the welding inspectors job is an ongoing process. A suc- cessful quality control program begins well before the first arc is struck. Therefore, the welding inspector must be familiar with many facets of the fabrication process. Before welding, the
15、 inspector will check drawings and specifications to determine such information as the con- figuration of the component, its specific weld quality re- quirements, and what degree of inspection is required. This review will also show the need for any special pro- cessing during manufacturing. Once we
16、lding begins, the welding inspector may observe various processing steps to assure that they are done properly. If all these subse- quent steps have been completed satisfactorily, then final inspection should simply confirm the success of those operations. Another benefit of this course is that it h
17、as been designed to provide the welding inspector with the necessary in- formation for the successful completion of the American Welding Societys Certified Welding Inspector (CWI) examination. The ten chapters listed below are sources for examination information. The welding inspector must have at l
18、east some knowledge in each of these ar- eas. Typically, the information presented will simply be a review, while sometimes it may represent an introduc- tion to a new topic. Chapter 1: Welding Inspection and Certification Chapter 2: Safe Practices for Welding Inspectors Chapter 3: Metal Joining and
19、 Cutting Processes Chapter 4: Weld Joint Geometry and Welding Symbols Chapter 5: Documents Governing Welding Inspection and Qualification Chapter 6: Metal Properties and Destructive Testing Chapter 7: Metric Practice for Welding Inspection Chapter 8: Welding Metallurgy for the Welding Inspector Chap
20、ter 9: Weld and Base Metal Discontinuities Chapter 10: Visual Inspection and Other NDE Methods and Symbols Chapter 1Welding Inspection and CertificationWELDING INSPECTION TECHNOLOGY CHAPTER 1WELDING INSPECTION AND CERTIFICATION 1-3 Additionally, selected technical references are included in the “Bod
21、y of Knowledge” required. These include: A Selected Code (AWS D1.1, API 1104, etc.) AWS CM, Certification Manual for Welding Inspectors AWS A1.1, Metric Practice Guide for the Welding Industry AWS A2.4, Standard Symbols for Welding, Brazing, and Nondestructive Examination AWS A3.0, Standard Welding
22、Terms and Definitions A W S B 1 . 1 0 , Guide for the Nondestructive Examina- tion of Welds AWS B1.11, Guide for the Visual Inspection of Welds ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes AWS QC1, Standard for AWS Certification of Weld- ing Inspectors A W S B 5 . 1 , Specification f
23、or the Qualification of Welding Inspectors Who is the Welding Inspector? Before turning our discussion to the technical subjects, let us talk about the welding inspector as an individual and the typical responsibilities that accompany the posi- tion. The welding inspector is a responsible person, in
24、- volved in the determination of weld quality according to applicable codes and/or specifications. In the perfor- mance of inspection tasks, welding inspectors operate in many different circumstances, depending primarily for whom they are working. Thus, there is a special need for job specifications
25、 due to the complexity of some compo- nents and structures. The inspection workforce may include destructive test- ing specialists, nondestructive examination (NDE) spe- cialists, code inspectors, military or government inspectors, owner representatives, in-house inspectors, and others. These indivi
26、duals may, at times, consider themselves “welding inspectors,” since they inspect welds as part of their job responsibility. The three gen- eral categories into which the welding inspectors work- functions can be grouped are: Overseer Specialist Combination OverseerSpecialist The Overseer is usually
27、 one who oversees the duties of several inspectors.The specialist, on the other hand, is an individual who does some specific task(s) in the inspec- tion process. A specialist may or may not act indepen- dently of an overseer. The nondestructive examination (NDE) specialist is an example of this cat
28、egory of in- spector. It is common to see inspectors serving as both overseer and specialist. Such an individual may be responsible for general weld quality judgments in each of the various fabrication steps, and be required to perform any nonde- structive testing that is necessary. Fabricators may
29、em- ploy several overseer type inspectors, each having their own area of general weld inspection responsibility. Be- cause inspection responsibility is divided in these cases, inspectors may have to rely on others for specific aspects of the total inspection program. For the purposes of this course,
30、 we will refer to the weld- ing inspector in general, without regard to how each indi- vidual will be used by an employer. It is impractical to address each individuals situation in the scope of this discussion. To emphasize the differences in job requirements, lets look at some industries using wel
31、ding inspectors. We see welding inspection being done in the construction of buildings, bridges and other structural units. Energy re- lated applications include power generation facilities, pressure vessels and pipelines, and other distribution equipment requiring pressure containment. The chemical
32、 industry also uses welding extensively in the fabrication of pressure-containing processing facilities and equip- ment. The transportation industry requires assurance of accurate weld quality in such areas as aerospace, auto- motive, shipbuilding, railroad apparatus and off-road equipment. Finally,
33、 the manufacturing of consumer goods often requires specific weld quality requirements. With the diversity shown by this listing, various situa- tions will clearly require different types and degrees of inspection. Important Qualities of the Welding Inspector The first, and perhaps the most importan
34、t quality, is a professional attitude. Professional attitude is often the key factor for welding inspector success. Inspector atti- tude often determines the degree of respect and coopera- tion received from others during the performance of inspection duties. Included in this category is the ability
35、 of the welding inspector to make decisions based on facts so that inspections are fair, impartial and consistent. ACHAPTER 1WELDING INSPECTION AND CERTIFICATION WELDING INSPECTION TECHNOLOGY 1-4 welding inspector must be completely familiar with the job requirements. Inspection decisions must be ba
36、sed on facts; the condition of the weld and the acceptance crite- ria specified in the applicable specification must be the determining factors. Inspectors will often find them- selves being “tested” by other personnel on the job, espe- cially when newly assigned to some task. Maintaining a professi
37、onal attitude helps overcome obstacles to suc- cessful job performance. The individual who does welding inspection should pos- sess certain qualities to assure that the job will be done most effectively. Figure 1.1 illustrates these qualities. Next, the welding inspector should be in good physical c
38、ondition. Since the primary job involves visual inspec- tion, obviously the welding inspector should have good vision, whether natural or corrected. The AWS CWI pro- gram requires the inspector to pass an eye examination, with or without corrective lenses, to prove near vision acuity on Jaeger J2 at
39、 not less than 12 in, and complete a color perception test. Another aspect of physical condi- tion involves the size of some welded structures. Welds can be located anywhere on very large structures, and in- spectors must often go to those areas and make evalua- tions. Inspectors should be in good e
40、nough physical condition to go to any location where the welder has Figure 1.1The Inspector Possesses a Great Amount of Knowledge, Attitudes, Skills, and Habits (KASH) Knowledge of drawings and specifications Knowledge of welding terms Knowledge of welding processes Knowledge of testing methods Prof
41、essional attitude Inspection experience Welding experience Safe practices Ability to maintain records Good physical condition Good vision Training in engineering and metallurgyWELDING INSPECTION TECHNOLOGY CHAPTER 1WELDING INSPECTION AND CERTIFICATION 1-5 been. This does not imply that inspectors mu
42、st violate safety regulations just to do their duties. Inspection can often be hampered if not done immediately after weld- ing, because access aids for the welder such as ladders and scaffolding may be removed, making inspection im- possible or dangerous. Within safety guidelines, welding inspector
43、s should not let their physical condition prevent them from doing the inspection properly. Another quality the welding inspector should develop is an ability to understand and apply the various documents describing weld requirements. These can include draw- ings, codes, standards and specifications.
44、 Documents provide most of the information regarding what, when, where and how the welding and subsequent inspections are to be done. Therefore, the rules or guidelines under which the welding inspector does the job can be found in these documents. They also state the acceptable quality requirements
45、 against which the welding inspector will judge the weld quality. It is important that these docu- ments are reviewed before the start of any work or pro- duction because the welding inspector must be aware of the job requirements. Often this pre-job review will re- veal required “hold points” for i
46、nspections, procedure and welder qualification requirements, special process- ing steps or design deficiencies such as weld inaccessi- bility during fabrication. Although welding inspectors should be thorough in their review, this does not mean that the requirements should be memorized. These are re
47、ference documents and should be readily available for detailed information any time in the fabrication process. Generally, inspectors are the individuals most familiar with all these documents so they may be called upon by others for information and interpretation regarding the welding. Most people
48、associated with welding inspection will agree that having inspection experience is very impor- tant. Textbooks and classroom learning cannot teach an inspector all of the things needed to inspect effectively. Experience will aid the welding inspector in becoming more efficient. Better ways of thinki
49、ng and working will develop with time. Experience will also help the inspec- tor develop the proper attitude and point of view regard- ing the job. Experience gained working with various codes and specifications improves an inspectors under- standing of welding requirements and generally im- proves job effectiveness. To emphasize the need for inspection experience, we often see a novice inspector paired with an experienced one so the proper techniques can be passed along. Finally, we see that inspector certi- fication programs require some minimum leve
