Welding Inspection Technology PDF 2008, American Welding Society

WELDING INSPECTION TECHNOLOGY FIFTH EDITION—2008 Published by American Welding Society Education Department Education Services WELDING INSPECTION TECHNOLOGY DISCLAIMER The American Welding Society, Inc. assumes no responsibility for the information contained in this publication. An independent,...

WELDING INSPECTION TECHNOLOGY FIFTH EDITION—2008 Published by American Welding Society Education Department Education Services WELDING INSPECTION TECHNOLOGY DISCLAIMER The American Welding Society, Inc. assumes no responsibility for the information contained in this publication. An independent, substantiating 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 Society All rights reserved Printed in the United States of America Photocopy Rights. No portion of this standard may be reproduced, stored in a retrieval system, or transmitted in any form, including mechanical, photocopying, recording, or otherwise, without the prior written permission of the copyright owner. Authorization to photocopy items for internal, personal, or educational classroom use only or the internal, personal, or educational classroom use only of specific clients is granted by the American Welding Society provided that the appropriate fee is paid to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, tel: (978) 750-8400; Internet: <www.copyright.com>. ii WELDING INSPECTION TECHNOLOGY 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 Qualification 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 iii 10-1 CHAPTER 1 Welding Inspection and Certification Contents Introduction ..................................................................................................................................................................1-20 Who is the Welding Inspector? ...................................................................................................................................1-30 Important Qualities of the Welding Inspector...........................................................................................................1-30 Ethical Requirements for the Welding Inspector......................................................................................................1-60 The Welding Inspector as a Communicator ..............................................................................................................1-60 Personnel Certification Programs...............................................................................................................................1-80 Key Terms and Definitions ..........................................................................................................................................1-11 1-1 CHAPTER 1—WELDING INSPECTION AND CERTIFICATION WELDING INSPECTION TECHNOLOGY Chapter 1—Welding Inspection and Certification Introduction quirements, and what degree of inspection is required. This review will also show the need for any special processing during manufacturing. Once welding begins, the welding inspector may observe various processing steps to assure that they are done properly. If all these subsequent steps have been completed satisfactorily, then final inspection should simply confirm the success of those operations. In today’s 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 economics, safety, government regulations, global competition, and the use of less conservative designs. While not singularly responsible for the attainment of weld quality, the welding inspector plays a large role in any successful welding quality control program. In reality, many people participate in the creation of a quality welded product. However, 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. Another benefit of this course is that it has been designed to provide the welding inspector with the necessary information for the successful completion of the American Welding Society’s Certified Welding Inspector (CWI) examination. The ten chapters listed below are sources for examination information. The welding inspector must have at least some knowledge in each of these areas. Typically, the information presented will simply be a review, while sometimes it may represent an introduction to a new topic. To do this job effectively, the welding inspector must have a wide range of knowledge and skills, because it involves more than simply looking at welds. Consequently, this course is specifically designed to provide both experienced and novice welding inspectors a basic background in the more critical job aspects. This does not imply, however, that each welding inspector will use all of this information while working for a particular company. Nor does it mean that the material presented will include all of the information for every welding inspector’s situation. Selection of these various topics is based on the general knowledge desirable for an individual to do general welding inspection. The important thing to realize is that effective welding inspection involves much more than just looking at finished welds. Section 4 of AWS QC1, Standard for AWS Certification of Welding Inspectors, outlines the various functions of the welding inspectors. You should become familiar with these various responsibilities because the welding inspector’s job is an ongoing process. A successful 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 inspector will check drawings and specifications to determine such information as the configuration of the component, its specific weld quality re- Chapter 1: Welding Inspection and Certification Chapter 2: Safe Practices for Welding Inspectors Chapter 3: Metal Joining and Cutting Processes Chapter 4: Weld Joint Geometry and Welding Symbols Chapter 5: Documents Governing Inspection and Qualification Chapter 6: Metal Properties Testing Chapter 7: Metric Practice for Welding Inspection Chapter 8: Welding Metallurgy for the Welding Inspector Chapter 9: Weld and Base Metal Discontinuities and Welding Destructive Chapter 10: Visual Inspection and Other NDE Methods and Symbols 1-2 WELDING INSPECTION TECHNOLOGY CHAPTER 1—WELDING INSPECTION AND CERTIFICATION The Overseer is usually 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 inspection process. A specialist may or may not act independently of an overseer. The nondestructive examination (NDE) specialist is an example of this category of inspector. Additionally, selected technical references are included in the “Body 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 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 nondestructive testing that is necessary. Fabricators may employ several overseer type inspectors, each having their own area of general weld inspection responsibility. Because inspection responsibility is divided in these cases, inspectors may have to rely on others for specific aspects of the total inspection program. • AWS A2.4, Standard Symbols for Welding, Brazing, and Nondestructive Examination • AWS A3.0, Standard Welding Terms and Definitions • AWS B1.10, Guide for the Nondestructive Examination of Welds • AWS B1.11, Guide for the Visual Inspection of Welds • ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes For the purposes of this course, we will refer to the welding inspector in general, without regard to how each individual will be used by an employer. It is impractical to address each individual’s situation in the scope of this discussion. • AWS QC1, Standard for AWS Certification of Welding Inspectors • AWS B5.1, Specification for the Qualification of Welding Inspectors To emphasize the differences in job requirements, let’s look at some industries using welding inspectors. We see welding inspection being done in the construction of buildings, bridges and other structural units. Energy related applications include power generation facilities, pressure vessels and pipelines, and other distribution equipment requiring pressure containment. The chemical industry also uses welding extensively in the fabrication of pressure-containing processing facilities and equipment. The transportation industry requires assurance of accurate weld quality in such areas as aerospace, automotive, shipbuilding, railroad apparatus and off-road equipment. Finally, the manufacturing of consumer goods often requires specific weld quality requirements. With the diversity shown by this listing, various situations will clearly require different types and degrees of inspection. 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 position. The welding inspector is a responsible person, involved in the determination of weld quality according to applicable codes and/or specifications. In the performance 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 due to the complexity of some components and structures. The inspection workforce may include destructive testing specialists, nondestructive examination (NDE) specialists, code inspectors, military or government inspectors, owner representatives, in-house inspectors, and others. These individuals may, at times, consider themselves “welding inspectors,” since they inspect welds as part of their job responsibility. The three general categories into which the welding inspectors’ workfunctions can be grouped are: Important Qualities of the Welding Inspector The first, and perhaps the most important quality, is a professional attitude. Professional attitude is often the key factor for welding inspector success. Inspector attitude often determines the degree of respect and cooperation received from others during the performance of inspection duties. Included in this category is the ability of the welding inspector to make decisions based on facts so that inspections are fair, impartial and consistent. A • Overseer • Specialist • Combination Overseer—Specialist 1-3 CHAPTER 1—WELDING INSPECTION AND CERTIFICATION WELDING INSPECTION TECHNOLOGY Next, the welding inspector should be in good physical condition. Since the primary job involves visual inspection, obviously the welding inspector should have good vision, whether natural or corrected. The AWS CWI program requires the inspector to pass an eye examination, with or without corrective lenses, to prove near vision acuity on Jaeger J2 at not less than 12 in, and complete a color perception test. Another aspect of physical condition involves the size of some welded structures. Welds can be located anywhere on very large structures, and inspectors must often go to those areas and make evaluations. Inspectors should be in good enough physical condition to go to any location where the welder has welding inspector must be completely familiar with the job requirements. Inspection decisions must be based on facts; the condition of the weld and the acceptance criteria specified in the applicable specification must be the determining factors. Inspectors will often find themselves being “tested” by other personnel on the job, especially when newly assigned to some task. Maintaining a professional attitude helps overcome obstacles to successful job performance. The individual who does welding inspection should possess certain qualities to assure that the job will be done most effectively. Figure 1.1 illustrates these qualities. Knowledge of drawings and specifications Knowledge of welding terms Knowledge of welding processes Knowledge of testing methods Professional attitude Training in engineering and metallurgy Inspection experience Welding experience Safe practices Ability to maintain records Good physical condition Good vision Figure 1.1—The Inspector Possesses a Great Amount of Knowledge, Attitudes, Skills, and Habits (KASH) 1-4