1、Visual Inspection Workshop Reference Manual Fourth Edition 2008 AWS VIW-M:2008 Education ServicesVisual Inspection Workshop Reference Manual Fourth Edition 2008 Published by American Welding Society Education Services AWS VIW-M:2008 550 N.W. LeJeune Road, Miami, FL 33126ii AWS Visual Inspection Work
2、shop 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: 978-0-87171-185-4 American W
3、elding Society 550 N.W. LeJeune Road, Miami, FL 33126 2008 by American Welding SocietyAll 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, photocopy
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5、Society provided that the appropriate fee is paid to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, tel: (978) 750-8400; Internet: .iii AWS Visual Inspection Workshop Table of Contents Chapter Page Introduction to the Workshop0 Rationale . 10 Workshop Aims 10 Quality 20 Terms
6、 and Definitions 20 Certified Welding Inspectors 40 Visual Inspection 40 Safety and Health 50 1. Visual Inspection of Welding 1.0 Aims of Chapter #1 1-10 1.1 Application. 1-10 1.2 Weldment and Joint Design. 1-20 1.3 Base Materials 1-20 1.4 Welding Procedures. 1-30 1.5 Welding Fabrication 1-30 1.6 In
7、spection. 1-30 2. Weld and Base Metal Discontinuities 2.0 Aims of Chapter #2 2-10 2.1 Weld Surface Conditions . 2-10 2.2 Porosity 2-10 2.3 Incomplete Fusion 2-40 2.4 Incomplete Joint Penetration . 2-40 2.5 Undercut. 2-70 2.6 Underfill. 2-70 2.7 Overlap. 2-80 2.8 Lamination . 2-80 2.9 Seams and Laps
8、. 2-90 2.10 Cracks 2-10 2.11 Slag Inclusions. 2-16 2.12 Excessive Reinforcement. 2-17 2.13 Convexity and Concavity. 2-18 2.14 Arc Strikes . 2-18 2.15 Spatter 2-19 2.16 Melt Through . 2-19 2.17 Weld Size. 2-19 2.18 Surface Oxidation 2-21 3. Welding Codes and Specifications 3.0 Aims of Chapter #3 3-10
9、 3.1 Introduction to Chapter #3. 3-10 3.2 Part B, Examination Book of Specifications . 3-40 3.3 List of Appendices . 3-50 3.4 PQRAppendix I 3-60 3.5 Performance Qualification Test RecordAppendix II . 3-80iv AWS Visual Inspection Workshop 3.6 Prequalified CJP Groove Welded JointsAppendix III. 3-11 3.
10、7 Pipe SchedulesAppendix IV 3-14 3.8 Weld Profile Acceptance ChartAppendix V and Weld Profile Acceptance DescriptionAppendix VI. 3-16 3.9 Visual Weld Inspection CriteriaAppendix VII 3-19 3.10 Required Test Results, Guided BendsAppendix VIII 3-21 3.11 Weld Metal AnalysisAppendix IX 3-23 3.12 Electrod
11、e GroupsAppendix X 3-25 3.13 Welder Qualification Test RequirementsAppendix XI 3-28 3.14 Welding Procedure QualificationAppendices XII and XIII 3-32 3.15 Matching Filler Metals and StrengthsAppendix XIV 3-36 3.16 Minimum Preheat and Interpass TemperaturesAppendix XV. 3-41 3.17 Radiographic TestingAp
12、pendix XVI . 3-45 3.18 Face and Root BendsAppendix XVI . 3-51 4. Measurements of Welds 4.0 Aims of Chapter #4 4-10 4.1 Introduction to Chapter #4. 4-10 4.2 Inspection Instruments and Gauges . 4-20 4.3 Undercut Gauge . 4-30 4.4 Machinists Rule 4-30 4.5 Vernier Micrometer . 4-50 4.6 Dial Caliper 4-10
13、4.7 Measurement Conversions. 4-14 4.8 Magnifier . 4-15 4.9 Linear Measuring Instrument Comparisons 4-15 4.10 Special Welding Gauges 4-16 4.11 Welding Math 4-20 Exercise QuestionsEQ-1 Chapter Pagev AWS Visual Inspection Workshop List of Figures Chapter Figure Page 1. Visual Inspection of Welding0 1.1
14、Restricted Access Joint for Welder Qualification Test 1-40 1.2Joint Tolerances: With and Without Backing 1-70 1.3Using a Temperature Indicating Crayon 1-80 2. Weld and Base Metal Discontinuities 2.1Scattered Porosity. 2-20 2.2Surface Appearance of Piping Porosity 2-30 2.3Aligned Porosity with Crack
15、2-30 2.4Elongated Porosity . 2-40 2.5Various Locations of Incomplete Fusion . 2-40 2.6Incomplete Fusion 2-50 2.7Incomplete Fusion at the Groove Face. 2-50 2.8Incomplete Fusion Between Weld Beads. 2-50 2.9Incomplete Fusion Between the Weld and Base Metal 2-60 2.10Incomplete Joint Penetration 2-60 2.1
16、1Incomplete Joint Penetration with Consumable Insert. 2-70 2.12Incomplete Joint Penetration 2-70 2.13Examples of Undercut 2-80 2.14Undercut at Fillet Weld Toe. 2-80 2.15Underfill . 2-90 2.16Underfill Using Flux Cored Arc Welding in Steel. 2-90 2.17Overlap . 2-10 2.18Overlap . 2-10 2.19Laminations 2-
17、11 2.20Types of Cracks 2-12 2.21Longitudinal vs. Transverse Cracks . 2-13 2.22Longitudinal Crack and Linear Porosity 2-13 2.23Transverse Cracks 2-13 2.24Throat Crack. 2-14 2.25Crater Crack . 2-14 2.26Longitudinal Cracks Propagating from Crater Crack. 2-15 2.27Toe Cracks 2-15 2.28Toe Cracks 2-16 2.29
18、Underbead Cracks 2-16 2.30Slag Inclusions . 2-17 2.31Weld Reinforcement. 2-17 2.32Convex Fillet Weld 2-18 2.33Convexity . 2-18 2.34Concave Fillet Weld. 2-19 2.35Spatter. 2-19 2.36Melt-Through . 2-20 2.37Surface Oxidation (Sugaring) in a Stainless Steel Gas Tungsten Arc Weld 2-21vi AWS Visual Inspect
19、ion Workshop Chapter Figure Page 4. Measurements of Welds 4.1Typical Instruments, Tools, and Gauges Used in Weld Inspection . 4-20 4.2Undercut Gauge 4-30 4.3Machinists Rule (Scale) Graduations 4-40 4.4Micrometer . 4-50 4.50 in to 1 in Micrometer and its Components 4-80 4.6Micrometer Zeroed. 4-90 4.7
20、Micrometer Readings . 4-10 4.8Reading the 0 in to 1 in Micrometer. 4-11 4.9Dial Caliper (Metric) 4-11 4.10Measuring with the Dial Caliper 4-12 4.11Reading the Dial Caliper 4-13 4.12Using the Extension Rod 4-13 4.13Magnifier 4-15 4.14The Palmgren Gauge 4-17 4.15Fillet Weld Profiles and Dimensions 4-1
21、8 4.16Fillet Weld Profiles 4-19 4.17Fillet Gauge 4-19 4.18Convex and Concave Fillet Weld Sizes . 4-20 4.19Fillet Weld Gauge 4-20AWS Visual Inspection Workshop Introduction 1 VISUAL INSPECTION OF WELDING INTRODUCTION Rationale Inspection is traditionally considered a post-processing activity. A machi
22、ne component may be turned to finished form and sizethen inspected for conformance to the appli- cable drawing or specification. A garment is inspected after sewing and all the buttons and other features are in place. In these and similar instances, visual inspection is carried out after the product
23、ion activities have been completed. In the case of weldments, experience has shown that post-processing inspection, even when supplemented with nondestructive examination (NDE), gives no guarantee of suitability for intended service. However, consistent results over a considerable period of time hav
24、e demonstrated the effectiveness of a preplanned sequence of visual inspections. If carried out at specific stages of weldment production, such programs give a high degree of assurance of meeting quality expectationsfrequently without recourse to NDE. With welding, the factors influencing quality ma
25、y manifest themselves at any stage of the production operation. In many instances, quality is compromised even before welding commences. In most such circumstances, suitably timed visual inspection would have revealed the shortcoming at a stage when corrective action would be simple to implement and
26、 inexpensive to carry out. Weld and weldment quality are determined by: Weldment and joint design Materials used in construction Welding procedures Manner of weld application Inspection program Visual welding inspection provides the basis for the effective control of these determinants. Workshop Aim
27、s The aims of this workshop are to: Provide a basic understanding of the circumstances under which weld and weld- ment quality, or both, may be compromised. Offer a program of weld inspection that gives a high degree of assurance of meeting weld quality requirements for most fabricated products. Sho
28、w how to develop and implement specific quality plans to meet all normal requirements for weld and weldment quality.AWS Visual Inspection Workshop Introduction 2 Demonstrate and practice the techniques of visual inspection required to carry out effective weld quality control. Quality The term qualit
29、y is widely used and applied. However, many times, the general con- cept of quality is misunderstood. Quality is conformance to the applicable specification. The required level of quality for a product or service is typically determined by the designer, based on suitability for service over the inte
30、nded life span. All product vari- ables must be specified in a manner that is capable of being measured. Dimensions are readily verified. Attributes such as surface finish, if significant, must be specified in terms allowing for precise determination or measurement. In carrying out an inspection, th
31、e inspectors task is to compare the actual with the required or specified product dimensions. Appearance alone is rarely the determinant of product quality. Terms and Definitions Certain important terms are used in the inspection of welding that may or may not apply in other industries. These includ
32、e: Discontinuityany interruption in the uniformity of an object. Defecta discontinuity that does not meet the required product specification. In general, a discontinuity is described as any interruption in the uniform nature of an item. Therefore, a bump in a highway could be considered to be a type
33、 of discontinu- ity because it interrupts the smooth, uniform surface of the pavement. In welding, the types of discontinuities with which we are concerned are such things as cracks, poros- ity, undercut, incomplete fusion, etc. Knowledge of these discontinuities is important to the welding inspecto
34、r for a number of reasons. First, the inspector will be asked to visually inspect welds to determine the presence of any of these discontinuities. If any are discovered, the welding inspector must then be capable of describing their nature, location, and extent. This information will be required to
35、determine whether or not that discontinuity requires repair, as described in the applicable job specifications. If additional treatment is deemed necessary, the welding inspector must be capable of accurately describing the discontinuity to the extent that it can be satisfactorily cor- rected by pro
36、duction personnel. Before describing these discontinuities, it is extremely important to understand the difference between a discontinuity and a defect. Too often, people mistakenly use the two terms interchangeably. As a welding inspector, you should strive to realize the distinction between the te
37、rms discontinuity and defect.AWS Visual Inspection Workshop Introduction 3 While a discontinuity is some feature which introduces an irregularity in an otherwise uniform structure, a defect is a specific discontinuity which can impair the suitability of that structure for its intended purpose. That
38、is, a defect is a discontinuity of a certain type, and one which occurs in an amount great enough to render that particular object or structure unsuitable for its intended service based on criteria in the applicable code. In order to determine if a particular discontinuity is actually a defect, ther
39、e must be some standard which defines the acceptable limits of that discontinuity. When its size or concentration exceeds these limits, it is deemed a defect. We can therefore think of a defect as a “rejectable discontinuity.” So, if we refer to some feature as a defect, we are implying that it is r
40、ejectable and requires some further treatment to bring it into acceptable limits to a particular code. Depending on the intended service of the part in question, an existing discontinuity may or may not be considered to be a defect. Consequently, each industry uses specific codes or standards which
41、describe the acceptable limits for those discontinuities which could affect the successful perfor- mance of various components. A code by definition is “a body of laws, as of a nation, city, etc., arranged systemati- cally for easy reference.” When a structure is built within the jurisdiction of a c
42、ity or state, it must often comply with certain “building codes.” Since a code consists of laws having legal status, it will always be considered mandatory. Therefore, we will see text containing words such as “shall” and “will.” A specific code includes certain conditions and requirements for the i
43、tem in question. Quite often it will also include descriptions of methods to determine if those conditions and requirements have been achieved. The next document type to be covered will be the standard. The dictionary describes a standard as, “something established for use as a rule or basis of comp
44、arison in mea- suring or judging capacity, quantity, content, extent, value, quality, etc.” A standard is treated as a separate document classification; however, the term standard also applies to numerous types of documents, including codes and specifications. Other types of documents considered to
45、be standards are procedures, recommended practices, groups of graphic symbols, classifications, and definitions of terms. Some standards are considered to be mandatory. This means the information is an absolute requirement. A mandatory standard is precise, clearly defined and suitable for adoption a
46、s part of a law or regulation. Therefore, the welding inspector must make judgments based on the content of these standards. These mandatory standards use such words as “shall” and “will” because their requirements are not a matter of choice. Codes are examples of mandatory standards because they ha
47、ve legal status. There are numerous standards that provide important information, but are considered to be nonmandatory. An example of a nonmandatory standard would be a recom- mended practice. They are nonmandatory because they may provide other ways in which objectives can be accomplished. Nonmand
48、atory standards include words such as “should” and “could” in place of “shall” and “will.” The implication here is that theAWS Visual Inspection Workshop Introduction 4 information has been put forth to serve as a guideline for the performance of a particu- lar task. However, it doesnt mean that som
49、ething is rejectable just because it fails to comply with that guideline. Even though a standard may be considered nonmanda- tory, it still provides important information. The final document classification to be discussed is the specification. This type is described as, “a detailed description of the parts of a whole: statement or enumeration of particulars, as to actual or required size, quality, performance, terms, etc.” A speci- fication is a detailed description or listing of required
