AWS G1.10M:2001 An American National Standard Guide for the Evaluation of Hot Gas, Hot Gas Extrusion, and Heated Tool Butt Thermoplastic Welds AWS G1.10M:2001 An American National Standard Key Words —Hot gas welding, thermoplastics, heated tool butt welding, joints, evaluation, testing, hot gas extrusion Approved by American National Standards Institute February 21, 2001 Guide for the Evaluation of Hot Gas, Hot Gas Extrusion, and Heated Tool Butt Thermoplastic Welds Prepared by AWS G1 Committee on Joining Plastics and Composites Under the Direction of AWS Technical Activities Committee Approved by AWS Board of Directors Abstract This standard lists and describes defects in hot gas, hot gas extrusion, and heated tool butt welded joints in thermoplastics. Its intent is to make possible a generally valid evaluation giving consideration to graded quality requirements. This standard encompasses the classification, requirements, testing, evaluation, and acceptance of the welds. Details in recording engineering data are described. Tables illustrating cracks, voids, solid inclusions, lack of fusion, defects of shape, and other defects in thermoplastic welds are included. Defect features with descriptions and illustrations are compiled into tables to aid in the evaluation of welds. 550 N.W. LeJeune Road, Miami, Florida 33126 Statement on Use of AWS American National Standards All standards (codes, specifications, recommended practices, methods, classifications, and guides) of the American Welding Society are voluntary consensus standards that have been developed in accordance with the rules of the American National Standards Institute. When AWS standards are either incorporated in, or made part of, documents that are included in federal or state laws and regulations, or the regulations of other governmental bodies, their provisions carry the full legal authority of the statute. In such cases, any changes in those AWS standards must be approved by the governmental body having statutory jurisdiction before they can become a part of those laws and regulations. In all cases, these standards carry the full legal authority of the contract or other document that invokes the AWS standards. Where this contractual relationship exists, changes in or deviations from requirements of an AWS standard must be by agreement between the contracting parties. International Standard Book Number: 0-87171-615-1 American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126 © 2001 by American Welding Society. All rights reserved Printed in the United States of America AWS American National Standards are developed through a consensus standards development process that brings together volunteers representing varied viewpoints and interests to achieve consensus. 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Anyone using these documents should rely on his or her own independent judgment or, as appropriate, seek the advice of a competent professional in determining the exercise of reasonable care in any given circumstances. This standard may be superseded by the issuance of new editions. Users should ensure that they have the latest edition. Publication of this standard does not authorize infringement of any patent. AWS disclaims liability for the infringement of any patent resulting from the use or reliance on this standard. Finally, AWS does not monitor, police, or enforce compliance with this standard, nor does it have the power to do so. Official interpretations of any of the technical requirements of this standard may be obtained by sending a request, in writing, to the Managing Director Technical Services, American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126 (see Annex C). With regard to technical inquiries made concerning AWS standards, oral opinions on AWS standards may be rendered. However, such opinions represent only the personal opinions of the particular individuals giving them. These individuals do not speak on behalf of AWS, nor do these oral opinions constitute official or unofficial opinions or interpretations of AWS. In addition, oral opinions are informal and should not be used as a substitute for an official interpretation. This standard is subject to revision at any time by the AWS G1 Committee on Joining of Plastics and Composites. It must be reviewed every five years and if not revised, it must be either reapproved or withdrawn. Comments (recommendations, additions, or deletions) and any pertinent data that may be of use in improving this standard are required and should be addressed to AWS Headquarters. Such comments will receive careful consideration by the AWS G1 Committee on Joining of Plastics and Composites and the author of the comments will be informed of the Committee’s response to the comments. Guests are invited to attend all meetings of the AWS G1 Committee on Joining of Plastics and Composites to express their comments verbally. Procedures for appeal of an adverse decision concerning all such comments are provided in the Rules of Operation of the Technical Activities Committee. A copy of these Rules can be obtained from the American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126. Photocopy Rights 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 (AWS) provided that the appropriate fee is paid to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, Tel: 978-750-8400; online: http://www.copyright.com. Personnel AWS G1 Committee on Joining of Plastics and Composites J. L. Frantz, Chair W. J. McMaster, Vice Chair J. L. Gayler, Secretary *A. Benatar *F. Dibble K. M. Dolan *D. Grewell *R. A. Grimm B. E. Gourley *F. He *K. A. Holt *S. Hunt L. T. Hutton V. A. Kagan *W. E. Kenney P. R. Krieger H. L. Mikeworth H. Moore T. O’Toole J. Park D. L. Pochardt *K. Stratman E. S. Stumpek *A. M. Summo M. W. Wichmann Branson Ultrasonics Corp. Honeywell American Welding Society The Ohio State University Crest Ultrasonics GE Plastics Branson Ultrasonics Corp. Edison Welding Institute Sonics & Materials, Inc. Eastman Kodak Co. Dukane Corp. Motorola, Inc. ATOFINA Chemicals Honeywell Consultant Fisher-Price, Inc. Dukane Corp. Eastman Kodak Co. Dukane Corp. Visteon 3M Co. Dukane Corp. EStumpek & Associates Dukane Corp. E. I. du Pont de Nemours and Co. AWS G1A Subcommittee on Hot Gas Welding and Extrusion Welding L. T. Hutton, Chair G. Hopkins, Vice Chair J. L. Gayler, Secretary *M. D. Beamish A. R. Blazejewski S. A. Burrows D. Chandler T. S. Dean *W. H. Drake, Jr. *R. P. Gaspar *J. J. Gates G. Glein *R. A. Grimm *P. Habib N. Hall D. K. Heffner ATOFINA Chemicals Plastek Werks, Inc. American Welding Society Baker College of Owosso Symalit AG ReynoldsTech Fabricators, Inc. Engiplast, Inc. Pro Poly of America, Inc. SW Missouri State University BFGoodrich AN-COR Industrial Plastics Inc. CERA Consulting Edison Welding Institute CPF Dualam, Inc. E. I. du Pont de Nemours and Co. Electrochemical Engineering and Manufacturing Co. *Advisor iii AWS G1A Subcommittee on Hot Gas Welding and Extrusion Welding (Continued) M. G. Jolley D. L. Keeler *W. E. Kenney P. R. Khaladkar L. K. Lewis *S. Linnemann A. Lopez G. W. McCuaig *R. Moubarac P. Mullen *J. E. Niesse *J. J. Ploskonka C. W. Renner *R. C. Reynard D. R. Robbins *A. Savitski B. L. Smith *T. J. Thorpe B. G. Waddingham T. R. Way L. Y. Woo G. K. Worthington C. E. Zarnitz D. Ziegler KCH Services, Inc. Viatec, Inc. Consultant DuPont Engineering DuPont Teflon® Films RL Industries, Inc. Dow Chemical Prolite Plastics Limited CPF Dualam, Inc. BFGoodrich Consultant HPG International Renner Associates, Inc. SCP Global Technologies Philip Services Corp. Edison Welding Institute Met-Pro Corp.—Duall Division Boeing Isothermal Community College ReynoldsTech Fabricators, Inc. Fabricated Plastics Limited Tri-Mer Corp. Atlas Minerals and Chemicals, Inc. Wegener NA, Inc. *Advisor The subcommittee would like to thank Dr. Detlef Van Hofe of DVS for his contributions to this standard. iv Foreword (This Foreword is not part of AWS G1.10M:2001, Guide for the Evaluation of Hot Gas, Hot Gas Extrusion, and Heated Tool Butt Thermoplastic Welds, but is included for information purposes only.) The purpose of plastics welding inspection is to determine if a plastics weldment meets the acceptance criteria of a specific code, other standard, or other document. The plastics welding inspector must be thoroughly familiar with plastics welding processes, plastics welding procedures, plastics welder qualifications, materials, the limitation of plastics weld testing, be able to read drawings, prepare and keep records, prepare and make reports and make responsible judgments. For plastics welding inspectors to be effective, the activities performed should be consistent with the requirements, and technical and ethical principles. The AWS G1 Committee on Joining Plastics and Composites was formed in 1989 by industry and academic experts interested in providing process information and test standards for rating the weldability of plastic and composite materials. The G1A Subcommittee on Hot Gas Welding and Extrusion Welding was formed in 1993 to create standards for the qualification of hot gas and heated tool plastic welding personnel. DVS 2202-1, Imperfections in thermoplastic welding joints; features, descriptions, evaluation, was used extensively in the creation of this standard. Comments and suggestions for the improvement of this standard are welcome. They should be sent to the Secretary, AWS G1 Committee on Joining of Plastics and Composites, American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126. Official interpretations of any of the technical requirements of this standard may be obtained by sending a request, in writing, to the Managing Director, Technical Services Division, American Welding Society (see Annex C). A formal reply will be issued after it has been reviewed by the appropriate personnel following established procedures. v Table of Contents Page No. Personnel .................................................................................................................................................................... iii Foreword.......................................................................................................................................................................v 1. Scope, Purpose, and Range of Application .............................................................................................................1 2. Referenced Documents............................................................................................................................................1 3. Definitions ...............................................................................................................................................................2 4. Evaluation Groups ...................................................................................................................................................2 4.1 Classification ...................................................................................................................................................2 4.2 Criteria for Establishment ...............................................................................................................................2 5. Requirements for Welded Joints ..............................................................................................................................2 5.1 Quality Features for Classification of the Weld (Annexes VII through IX) ...................................................2 6. Details In Engineering Data.....................................................................................................................................2 7. Testing and Evaluation.............................................................................................................................................3 7.1 Evaluation........................................................................................................................................................3 7.2 Reworking Defective Welded Joints ...............................................................................................................3 7.3 Overlapping Defects........................................................................................................................................3 8. Acceptance...............................................................................................................................................................3 Annexes—Mandatory Information Annex I—Cracks ...........................................................................................................................................................5 Annex II—Voids ............................................................................................................................................................7 Annex III—Solid Inclusions ..........................................................................................................................................9 Annex IV—Lack of Fusion..........................................................................................................................................11 Annex V—Defects of Shape ........................................................................................................................................13 Annex VI—Other Defects............................................................................................................................................15 Annex VII—Description of Evaluation Groups for Hot Gas Fan and Speed Welds ...................................................17 Annex VIII—Description of Evaluation Groups for Hot Gas Extrusion Welds..........................................................21 Annex IX—Description of Evaluation Groups for Heated Tool Butt Welds ...............................................................25 Annexes—Nonmandatory Information Annex A—Other Documents.......................................................................................................................................29 Annex B—Document Sources .....................................................................................................................................31 Annex C—Guidelines for Preparation of Technical Inquiries for AWS Technical Committees .................................33 AWS List of Documents on Plastics Welding ..............................................................................................................35 vii AWS G1.10M:2001 Guide for the Evaluation of Hot Gas, Hot Gas Extrusion, and Heated Tool Butt Thermoplastic Welds 1. Scope, Purpose, and Range of Application Abbreviation Material Description PVC-HI PVC-U PVDF PVDF/HFP 1.1 These guidelines list and describe defects in welded joints in thermoplastic materials. The objective is to make possible a generally valid evaluation giving consideration to graded quality requirements. 1.6 The use of these guidelines for welding other thermoplastic materials must be agreed upon between the customer and the fabricator. 1.2 By classification into one of the evaluation groups in 4.1, specific defects can be excluded or kept within limits when welded joints are produced. 1.7 This standard makes use of the International System of Units (SI). 1.3 The application of these guidelines and the measures through which they can be met may be included in contractual specification or form part of the generally recognized specifications. 1.8 Safety. The activities described in this document may bring the user of this standard in contact with processes and materials that may be hazardous to the user’s health. Safety precautions mandated by OSHA and recommendations for material handling in MSDS sheets should be observed. The fabricator’s operating manual and safety instructions should always be carefully studied and complied with when operating equipment. 1.4 Welding Processes. Defects produced by the following welding processes are addressed. This guide applies to the following processes: Abbreviation Annex WF WZ WE HS VII VII VIII IX Hot gas fan (rod) welding Hot gas speed welding Hot gas extrusion welding Heated tool butt welding High-impact polyvinyl chloride Unplasticized polyvinyl chloride (rigid PVC) Polyvinylidene fluoride Polyvinylidene fluoride/hexafluoropropylene Note: This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user to establish appropriate safety and health practices. The user should determine the applicability of any regulatory limitations prior to use. 1.5 Materials. These guidelines apply to welded joints on components and systems made from the engineering thermoplastics listed below: Abbreviation Material Description ECTFE ETFE FEP MFA M PTFE PE-HD PFA PP-B PP-H PP-R PTFE PVC-C Ethylene chlorotrifluoroethylene Ethylene tetrafluoroethylene Fluorinated ethylene-propylene Perfluoromethylvinylether PFA modified PTFE High density polyethylene (rigid PE) Perfluoroalkoxy Polypropylene block copolymer Polypropylene homopolymer Polypropylene random copolymer Polytetrafluoroethylene Chlorinated polyvinyl chloride 2. Referenced Documents Reference should be made to the latest edition of the following documents: ASTM C 904 Standard Terminology Relating to ChemicalResistant Nonmetallic Materials1 1. ASTM documents are available from the American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959. 1 AWS G1.10M:2001 ASTM D 5162 Test Method B: Standard Practice for Discontinuity (Holiday) Testing of Nonconductive Protective Coating on Metallic Substrates1 AWS A3.0 The requirements to be established for the welded joints on a component should in each case be restricted to those which are necessary and appropriate for the application. 4.2 Criteria for Establishment. In the establishment of the evaluation groups, the following factors, among others, should be taken into account: (1) level and type of stress (for example static, dynamic) (2) thermoplastic material (for example viscous, brittle) (3) operating conditions (for example stationary, mobile, environmental) (4) production conditions (for example workshop, construction site) (5) potential hazards (for example hazardous gases and/or hazardous fluids) Standard Welding Terms and Definitions2 3. Definitions The terms used in this specification are defined in ASTM C 904, Terminology Relating to Chemical-Resistant Nonmetallic Materials, and AWS A3.0, Standard Welding Terms and Definitions. Exceptions, within the context of this standard, are listed below with their definitions. bead-stop crack. A crack occurring at the restarting of a weld due to the thermal characteristics of an overstressed weld rod. Thermoplastic materials exhibit thermal characteristics that contribute to this condition. 5. Requirements for Welded Joints 5.1 Quality Features for Classification of the Weld (Annexes VII through IX). The requirements for classifying a welded joint within a particular quality grade are established in the evaluation groups. In the majority of cases, requirements are established for the joint listing specific features, and describing them with reference to the internal and external state of the joint. By using Annexes VII through IX, it is possible to specify requirements for the quality of welding. Using individual features, i.e. through the type and extent of the defects, an evaluation of welded joints can then be undertaken (for example, as part of the acceptance procedure for the component). shrinkage groove. Insufficiency of material on the lateral edges of the weld due to the high thermal shrinkage or expansion characteristics of thermoplastics; this resembles an undercut or underfill weld. spark testing. An electronic test to locate discontinuities in a nonconductive material backed by a conductive substrate (Reference ASTM D 5162, Test Method B). void. An unfilled space within a weld. 4. Evaluation Groups 5.1.1 Requirements for Characteristics. This covers additional data such as: (1) deformation resistance (for example welding factor) (2) ductility (for example bending angle to cracking) (3) resistance to chemical attack (for example resistance factor) 4.1 Classification. Specific requirements are established for the intended service of a component, particularly regarding the quality of the welded joints. The following classification is used as a basis, so that the fabricator and inspector know the extent of the measures required for quality control with regard to welding. Evaluation Group 5.1.2 Requirements for Post Weld Treatment. In certain cases, it may be necessary to process the weld joint for the following reasons: (1) dynamic stress (for example notch-free transitions) (2) to smooth weld surfaces (for example lining) (3) to improve flow behavior (for example internal beads) (4) for technical inspection It is advisable to test and/or evaluate the weld both before and after machining. Requirement Level I High requirements for reliability and/or intended service. II Medium requirements for reliability and/or intended service. III Low requirements for reliability and/or intended service. 2. AWS documents are available from Global Engineering Documents, An Information Handling Services Group Company, 15 Inverness Way East, Englewood, Colorado 80112-5776. Telephones (800) 854-7179, (303) 397-7956; FAX (303) 397-2740; Internet: www.global.ihs.com. 6. Details in Engineering Data Requirements for welded joints are to be specified in the contract documentation that is binding for fabrication 2 AWS G1.10M:2001 imperfections in weld joints, and should be used in the evaluation and documentation process. The test reports should be used to determine points where the results do not correspond with the requirements. Should the component, or individual welded joints, not correspond to the evaluation group specified (4.1), then it or they must be reworked. (for example, working drawing, welding diagram), with reference to this standard. As a rule it is sufficient to identify a weld in accordance with the following example: WZ-VV-II where 7.2 Reworking Defective Welded Joints. When allowed under the contract and insofar as the inspector considers it possible, defective welded joints may be reworked. The purpose of reworking operations is to obtain the welded joint quality established by the requirements. If necessary, the results should be determined by additional testing. WZ = abbreviation for the welding process V = welding symbol and measurements II = evaluation group code Should all the welded joints on a component come under the same evaluation group, then it can be entered in a space provided for this purpose on the drawing. Example: All welded joints as per evaluation group II (see 4.1). Additional requirements for specification of the characteristics of welded joints and for machining are also to be noted in the engineering data. 7.3 Overlapping Defects. Should two or more types of defect arise simultaneously on welded joints, the cumulative effect of the individual defects may result in more than the sum. Tests should then be carried out to ascertain whether the welded joint still meets the requirements established or whether restrictions have to be imposed as regards safety and quality standards because of the accumulation of defects. In certain circumstances, the component or its welded joints should be re-classified into another evaluation group. 7. Testing and Evaluation Visual inspection, measurements and, where necessary, suitable non-destructive or destructive testing procedures are to be used to verify that the requirements for the individual welding groups have been met. Testing may be carried out on the welded joints of the component. Specific characteristics can also be verified on test pieces that are fabricated under comparable conditions. The nature and extent of the tests, together with their timing, are to be agreed upon between the customer and the fabricator. The test results are to be documented. 8. Acceptance Insofar as tests on the welded component confirm that it meets the requirements established in the technical documentation, the welded component shall be considered as being accepted and documented. Should the requirements not be met, and should reworking not be possible, then the fabricator and the end user should reach an agreement on the disposition of the welded component. 7.1 Evaluation. The test results form the basis for the classification of welded joints into one of the three evaluation groups by welding process, in accordance with Annexes VII through IX. Annexes I through VI define 3 AWS G1.10M:2001 Annex I Cracks (This Annex is a part of AWS G1.10M:2001, Guide for the Evaluation of Hot Gas, Hot Gas Extrusion, and Heated Tool Butt Thermoplastic Welds, and includes mandatory requirements for use with this standard.) No. Designation 100 Crack Break in continuity which may occur during cooling or through the action of stress, in the solid state 1001 Microcrack Crack having microscopic dimensions 101 Longitudinal crack Crack whose main direction is close to that of the axis of the weld. It can be situated: • in the weld • in the fusion zone (weld junction) • in the heat-affected zone • in the base material Transverse crack Crack whose direction is more or less perpendicular to the axis of the weld. It can be situated: • in the weld • in the heat-affected zone • in the base material Radiating crack Group of cracks issuing from a single point and situated: • in the weld • in the heat-affected zone • in the base material Bead-stop crack Crack occurring at the bead-stop, and which may be: 1011 1012 1013 1014 102 1021 1022 1023 103 1031 1032 1033 104 1041 1042 1043 Notes Illustrations • parallel • perpendicular • radiating (Continued) 5 AWS G1.10M:2001 Annex I—Cracks (Continued) No. Designation Notes 105 Group of disconnected cracks Set of grouped cracks of any orientation, which may be situated: • in the weld • in the heat-affected zone • in the base material 1051 1052 1053 106 1061 1062 1063 Illustrations Branching crack Set of interconnected cracks in the form of branching and distinguishable from the network of disconnected cracks (105) and from radiating cracks (103). They may be situated: • in the weld • in the heat-affected zone • in the base material 6 AWS G1.10M:2001 Annex II Voids (This Annex is a part of AWS G1.10M:2001, Guide for the Evaluation of Hot Gas, Hot Gas Extrusion, and Heated Tool Butt Thermoplastic Welds, and includes mandatory requirements for use with this standard.) No. Designation Notes Illustrations 201 Gas void Void formed by gas(es) 2011 Spheroidal gas pore More or less spherical gas void 2012 Uniformly distributed voids Spheroidal gas voids regularly distributed in the weld. To be distinguished from linear voids (2014). 2013 Localized (clustered) voids Group of gas voids 2014 Linear voids Gas voids distributed along a line parallel to the axis of the weld 2015 Elongated void Large non-spheroidal gas void whose main dimension is parallel to the axis of the weld generally situated close to the root 2016 Wormhole Gas void in the form of a worm gallery in the weld, resulting from the advance of the gases. Sometimes in herringbone pattern. Some wormholes can open out onto the surface. (Continued) 7 AWS G1.10M:2001 Annex II—Voids (Continued) No. Designation Notes Illustrations 2017 Surface pore Small gas void opening out on the surface 202 Shrinkage void Void due to shrinkage of weld during solidification 2024 Bead-stop or void Void (or depression) at pass-end not eliminated before or during the execution of the following pass 8 AWS G1.10M:2001 Annex III Solid Inclusions (This Annex is a part of AWS G1.10M:2001, Guide for the Evaluation of Hot Gas, Hot Gas Extrusion, and Heated Tool Butt Thermoplastic Welds, and includes mandatory requirements for use with this standard.) No. Designation Notes Illustrations 300 Solid inclusion Foreign solid body trapped in the weld 303 Oxides inclusion Oxides or burns trapped in the weld 304 Sundry inclusion Particle of foreign body trapped in the weld 9 AWS G1.10M:2001 Annex IV Lack of Fusion (This Annex is a part of AWS G1.10M:2001, Guide for the Evaluation of Hot Gas, Hot Gas Extrusion, and Heated Tool Butt Thermoplastic Welds, and includes mandatory requirements for use with this standard.) No. Designation Notes 401 Lack of fusion (incomplete fusion) Lack of fusion between deposited and base material or between two adjacent layers of deposited material. One must distinguish between: • the lack of lateral fusion • the lack of fusion between weld passes • the lack of fusion at the root of the weld Lack of interior fusion or incomplete penetration Partial absence of fusion of the edges to be welded, allowing an unfused area to remain between these edges 4011 4012 4013 402 Illustrations 11 AWS G1.10M:2001 Annex V Defects of Shape (This Annex is a part of AWS G1.10M:2001, Guide for the Evaluation of Hot Gas, Hot Gas Extrusion, and Heated Tool Butt Thermoplastic Welds, and includes mandatory requirements for use with this standard.) No. Designation Notes Illustrations 500 Imperfect shape External surface displays lack of geometric conformity relative to correct profile 5011 Continuous undercut Lack of material in form of a groove extending along a certain length of the edges of the weld, between beads or between flash 5012 Undercut Local lack of material situated on the edges of the weld 5013 Shrinkage groove Insufficiency of material on the lateral edges of the root 502 Excessive reinforcement Excess of deposited material or excessive flash 503 Excessive convexity Fault in an angle weld characterized by an exaggerated convex profile (Continued) 13 AWS G1.10M:2001 Annex V—Defects of Shape (Continued) No. Designation Notes Illustrations 504 Excessive melt through Excess of material at the root for a weld executed from a single face 505 Bad reinforcement angle Dihedral angle (α) formed by the plane tangent to the base and passing through the connection line is too great 506 Overlap Excess of weld which spreads over the surface of the base material, without fusion with same 507 Linear misalignment Non-observance of proposed level between two welded pieces. This defect is generally expressed by measurement of a level difference 508 Angular misalignment Non-observance of proposed angle between two welded pieces 511 Underfill Local or continuous insufficiency of weld leading to a bead profile which has shrunk relative to the correct profile 512 Symmetry defect • Non-symmetrical flash • Non-symmetrical angle weld 513 Irregular width Excessive variation in weld width 514 Irregular surface Excessive irregularity in surface of weld (roughness, corrugation) 517 5171 5172 Poor restart Local irregularity in surface at location of a restart: • in the terminal pass • in the bottom pass 14 AWS G1.10M:2001 Annex VI Other Defects (This Annex is a part of AWS G1.10M:2001, Guide for the Evaluation of Hot Gas, Hot Gas Extrusion, and Heated Tool Butt Thermoplastic Welds, and includes mandatory requirements for use with this standard.) No. Designation Notes 600 Other defects Defects not included in Annexes I, II, III, IV, and V 601 Thermal heat damage Superficial alteration resulting from the accidental action of a source of heat. It may affect: • the weld • the heat-affected zone • the base material Mechanical damage Local damage to the base material 6011 6012 6013 603 6031 Local damage due to an incorrect grinding or milling Local damage due to an incorrect scraping 6032 604 Illustrations Leg length defect Dimensional deviation of the specified leg lengths of the weld 15 AWS G1.10M:2001 Annex VII Description of Evaluation Groups for Hot Gas Fan and Speed Welds (This Annex is a part of AWS G1.10M:2001, Guide for the Evaluation of Hot Gas, Hot Gas Extrusion, and Heated Tool Butt Thermoplastic Welds, and includes mandatory requirements for use with this standard.) Evaluation Groups No. Feature Description I II III External state of surface of V-welds and double V-welds 1 Crack Isolated cracks or groups of cracks with and without branching, running lengthwise or crosswise to weld. They can lie: • in the weld • in the base material • in the heat-affected zone Not permissible Not permissible Not permissible 2 Welding overlap Marked deepening, which can be seen and felt, along or between individual welding rods, caused by, for example: • faults on die • poor welding rod guidance Not permissible Locally permissible if k>0 Locally permissible if k>0 3 Undercuts Notches in base material along weld caused by, for example: • penetration of die edge • machining of weld • unsatisfactory edge zone welding Not permissible Locally permissible if ending flat ∆s < 0.1s, but max = 1 mm Locally permissible if ending flat ∆s < 0.1s, but max = 1 mm 4 Incomplete joint penetration Notches caused by incomplete weld filling at root, due to, for example: • generating angle too small during edge preparation • root gap too small • root rod too thick • welding force too small Not permissible Not permissible Locally permissible in limited numbers if ∆s < 0.1s (Continued) 17 AWS G1.10M:2001 Annex VII—Description of Evaluation Groups for Hot Gas Fan and Speed Welds (Continued) Evaluation Groups No. Feature Description I II III 5 Incomplete joint penetration Caused by, for example: • inadequate edge preparation Not permissible Not permissible Locally permissible in limited numbers if ∆s < 0.1s, but max = 1 mm 6 Excessive melt through Caused by, for example: • root gap too big • compressed stringer bead Locally permissible in limited numbers if ∆s < 0.15s, but max = 2 mm Permissible if ∆s < 0.2s, but max = 3 mm Permissible if ∆s < 0.25s, but max = 4 mm 7 Excessive face reinforcement Caused by, for example: too many individual rods or passes • wrong edge preparation Continuously permissible if 0.1s < ∆s < 0.4s Continuously permissible if 0.05s < ∆s < 0.5s Continuously permissible if 0 < ∆s < 0.6s 8 Underfill Inadequate weld filling Not permissible Not permissible Not permissible 9 Linear misalignment For example: • different wall thicknesses are not compensated • equal wall thicknesses are misaligned Permissible if e1 < 0.1s, e2 < 0.15s, but max = 2 mm Permissible if e1 < 0.15s, e2 < 0.2s, but max = 4 mm Permissible if e1 < 0.2s, e2 < 0.25s, but max = 5 mm 10 Angular misalignment (errors of form) (Diagram) Permissible if e < ± 1 mm Permissible if e < ± 2 mm Permissible if e < ± 4 mm 11 Weld intersections (Diagram) Not permissible Not permissible Not permissible For example: • four-way intersection (Continued) 18 AWS G1.10M:2001 Annex VII—Description of Evaluation Groups for Hot Gas Fan and Speed Welds (Continued) Evaluation Groups No. Feature Description I II III 12 Wavy weld surface Waviness running vertical to weld in finishing pass, caused by, for example: • welding force and speed non-uniformly distributed Locally permissible Continuously permissible Continuously permissible 13 Rough weld surface Fine open bubbles, streaks, or nodules and the like, caused by, for example: • dirty welding shoe • hot gas temperature too high Isolated cases permissible Limited areas permissible Permissible 14 Start fault Incomplete welded cross section at start or end of weld Not permissible Small reduction in cross section permissible without abrupt transition Permissible 15 Heat damage Discoloration, nodule formation, high-gloss weld faces and similar defects Not permissible Isolated cases permissible Limited areas permissible External state of weld surface of fillet welds 16 Oversized weld (Diagram) Exceeds standard fillet weld thickness of a = 0.7s (s = thickness of thinner member) Permissible if b < 0.4a, but max = 6 mm Permissible if b < 0.5a, but max = 9 mm Permissible if b < 0.6a, but max = 12 mm 17 Undersized weld (Diagram) Undershoots standard fillet weld thickness of a = 0.7s (s = thickness of thinner member) Not permissible Permissible if nominal dimension is a slightly undershot locally b < 0.15a Permissible if nominal dimension a is undershot locally b < 0.3a (Continued) 19 AWS G1.10M:2001 Annex VII—Description of Evaluation Groups for Hot Gas Fan and Speed Welds (Continued) Evaluation Groups No. Feature 18 Incompletely welded cross section Description I II III Weld geometry not to standard Not permissible Permissible if z < 0.15a Permissible if z < 0.3a Internal state of V-welds and fillet welds 19 Pores and foreign material inclusions Numerous, dispersed, isolated or locally concentrated pores or inclusions, e.g., due to: • vaporization during welding (water, solvent) • dirty heated tool Small isolated pores permissible if ∆s < 0.05s Pores and pore rows permissible if ∆s < 0.1s Pores and pore rows permissible if ∆s < 0.15s 20 Lack of fusion Lack of fusion running horizontally or vertically in the weld or on the weld edges, caused by, for example: • welding temperature too low • dirty joint faces Not permissible Not permissible Not permissible (Continued) 20 AWS G1.10M:2001 Annex VIII Description of Evaluation Groups for Hot Gas Extrusion Welds (This Annex is a part of AWS G1.10M:2001, Guide for the Evaluation of Hot Gas, Hot Gas Extrusion, and Heated Tool Butt Thermoplastic Welds, and includes mandatory requirements for use with this standard.) Evaluation groups No. Feature Description I II III External state of surface of V-welds or double V-welds 1 Crack Isolated cracks or groups of cracks with and without branching, running lengthwise or crosswise to weld. They can lie: • in the weld • in the base material • in the heat-affected zone Not permissible Not permissible Not permissible 2 Undercut Continuous or local flat deformations lengthwise to weld, caused by, for example: • fault in welding shoe • fault in welding unit guidance Not permissible Locally permissible if k>0 Locally permissible if k>0 3 Undercuts Notches in base material along weld, caused by, for example: • penetration of weld shoe edges • processing of edge zone Locally permissible if ending flat and ∆s < 0.1s, but max = 1 mm Continuously permissible if ending flat and ∆s < 0.1s, but max = 2 mm Continuously permissible if ending flat and ∆s < 0.2s, but max = 3 mm 4 Inadequate edge zone welding Inadequate covering of welding groove edge on one or both sides Nominal dimension: ∆b > 3 mm Not permissible Locally permissible with notchfree transition and ∆ > 2 mm Continuously permissible with notch-free transition and ∆b > 1 mm (Continued) 21 AWS G1.10M:2001 Annex VIII—Description of Evaluation Groups for Hot Gas Extrusion Welds (Continued) Evaluation groups No. Feature Description I II III 5 Incomplete joint penetration Notches caused by inadequate weld filling on root, caused by, for example: • bend up and unwelded joint faces • root opening too small • welding force too small • root falling back due to shrinkage Not permissible Locally permissible in limited numbers if ∆s < 0.1s, but max = 1 mm Permissible if ∆s < 0.1s, but max = 1 mm 6 Incomplete joint penetration Caused by, for example: • inadequate edge preparation Not permissible Not permissible Locally permissible in limited numbers if ∆s <0.1s, but max = 1 mm 7 Excessive melt through Caused by, for example: • root opening too big • welding force too great Permissible if ∆s < 0.15s, but max = 2 mm Permissible if ∆s < 0.2s, but max = 3 mm Permissible if ∆s < 0.25s, but max = 4 mm 8 Excessive face reinforcement Finish pass too high, caused by, for example: • inadequately formed welding shoe • welding force too small Continuously permissible 0.1s < ∆s < 0.4s, but max = 6 mm Continuously permissible 0.05s < ∆s < 0.5 s, but max = 9mm Continuously permissible if 0 < ∆s < 0.6s, but max = 12 mm 9 Overlap Welding material overflow on one or both sides, usually without sufficient fusion to base material Not permissible Locally permissible in small numbers if ∆b < 5 mm Continuously permissible if ∆b < 5 mm 10 Underfill Weld cross section is not obtained, caused by, for example: • shrinkage of welding filler • inadequately formed welding shoe • welding speed too high Not permissible Not permissible Locally conditionally permissible if ∆s < 0.1s, but max = 1 mm (Continued) 22 AWS G1.10M:2001 Annex VIII—Description of Evaluation Groups for Hot Gas Extrusion Welds (Continued) Evaluation groups No. Feature Description I II III 11 Linear misalignment (Diagram) For example: • different wall thicknesses are not compensated Permissible if e1 > 0.1s, e2 > 0.15s, but max = 2 mm Permissible if e1 > 0.15s, e2 > 0.2s, but max = 4 mm Permissible if e1 > 0.2s, e2 > 0.25s, but max = 5 mm 12 Angular misalignment (defects of form) (Diagram) Length, L, of shorter side is decisive for permissible deflection Permissible up to e < ±1 mm Permissible up to e < ±2 mm Permissible up to e < ±4 mm 13 Weld intersections For example: • four-way intersection Not permissible Not permissible Not permissible 14 Asymmetrical weld cover Welding shoe has been guided outside weld center Not permissible Permissible if the required weld cross section is not undershot Locally conditionally permissible if ∆s < 0.1s, but max = 1 mm 15 Wavy weld surface Caused by, for example: • welding force nonuniformly applied Locally permissible Continuously permissible Continuously permissible 16 Rough weld surface Fine open bubbles, streaks, or nodules and similar defects, for example: • moisture in form mass • form mass temperature too low Isolated spots permissible Limited areas permissible Permissible 17 Start fault Incompletely welded cross section at start or end of weld Not permissible Not permissible Low reduction in cross section without sharp transitions permissible 18 Heat damage Discoloration, formation of nodules, high-gloss weld surfaces and similar defects Not permissible Isolated spots permissible Limited areas permissible (Continued) 23 AWS G1.10M:2001 Annex VIII—Description of Evaluation Groups for Hot Gas Extrusion Welds (Continued) Evaluation groups No. Feature Description I II III External state of weld surfaces of fillet welds 19 Oversized weld (Diagram) Exceeding of standard fillet weld thickness of a = 0.7s (s = thickness of thinner member) Permissible if b < 0.4a, but max = 6 mm Permissible if b < 0.5a, but max = 9 mm Permissible if b < 0.6a, but max = 12 mm 20 Undersized weld (Diagram) Required weld cross section is not obtained, caused by, for example: • shrinkage of welding filler • inadequately formed welding shoe Not permissible Permissible if nominal dimension and slightly undershot locally b < 0.15a Permissible if nominal dimension and undershot locally b < 0.3a 21 Incompletely welded weld cross section (Diagram) Weld geometry not to standard Not permissible Permissible if z < 0.15a Permissible if z < 0.3a 22 Pores due to foreign material inclusions Numerous, dispersed, isolated, or locally concentrated pores or inclusions, e.g., due to: • vaporization during welding (water, solvent) • dirty heated tool Small isolated pores permissible if ∆s < 0.05s Pores and pore rows permitted if ∆s < 0.1s Pores and pore rows permitted if ∆s < 0.15s 23 Lack of fusion No fusion, or incomplete fusion on opposite position, fastening points and weld sides, caused by, for example: • dirty joint • welding force too small • inadequate heating Not permissible Not permissible Locally conditionally permissible (Continued) 24 AWS G1.10M:2001 Annex IX Description of Evaluation Groups for Heated Tool Butt Welds (This Annex is a part of AWS G1.10M:2001, Guide for the Evaluation of Hot Gas, Hot Gas Extrusion, and Heated Tool Butt Thermoplastic Welds, and includes mandatory requirements for use with this standard.) Evaluation Groups No. Feature Description I II III External State of Joint 1 Cracks Cracks running lengthwise or crosswise to weld. They may be located: • in weld • in base material • in heat-affected zone Not permissible Not permissible Not permissible 2 Weld undercut Continuous or local notches length-wise to weld with root of the notch below the surface of the base material. Caused by, for example: • insufficient joint pressure • warming-up time too short • cooling time too short Not permissible Not permissible Not permissible 3 Notches and flutes Notches in edge of base material, lengthwise or crosswise to weld. Caused by, for example: • clamping tools • incorrect transport • fault in edge preparation Locally permissible if ending flat and ∆s < 0.1s, but max = 0.5 mm Locally permissible if ending flat and ∆s < 0.1s, but max = 1 mm Locally permissible if ending flat and ∆s < 0.15s, but max 2 = mm 4 Linear misalignment Joint faces are misaligned relative to one another or thickness variations are not corrected Permissible if e < 0.1s, but max = 2 mm Permissible if e < 0.15s, but max = 4 mm Permissible if e < 0.2s, but max = 5 mm (Continued) 25 AWS G1.10M:2001 Annex IX—Description of Evaluation Groups for Heated Tool Butt Welds (Continued) Evaluation Groups No. Feature 5 Angular misalignment 6 Description I II III Permissible if e < 3 mm Permissible if e < 5 mm Permissible if e < 7 mm Narrow, excessive welding flash* Excessive and sharp-edged welding flash over part or all of weld length due to wrong welding parameters, especially caused by: • excessive joint pressure with polyolefins only Not permissible Not permissible Not permissible 7 Non-uniform welding flash Non-angular joint planes, leading to variations in form of welding flash over part or all of weld length. Caused by, for example: • edge preparation fault • incorrect welding unit Permissible if b1 > 0.7b2 Permissible if b1 > 0.6 b2 Permissible if b1 > 0.5b2 8 Thermal damage High-gloss welding flash face with voids or nodules, usually associated with faulty welding flash formation and marked bead notches Not permissible Not permissible Not permissible 9 Lack of fusion No fusion or incomplete fusion on joint faces, over part or whole of weld cross section. Caused by, for example: • contaminated joint faces • oxidized joint faces • excessive reversal time • heated tool temperature too low Not permissible Not permissible Not permissible 10 Blowhole Hollow space in joint planes. Caused by, for example: • insufficient joint pressure • insufficient cooling time Not permissible Not permissible Not permissible For example: • machine fault • layout fault (Continued) 26 AWS G1.10M:2001 Annex IX—Description of Evaluation Groups for Heated Tool Butt Welds (Continued) Evaluation Groups No. Feature 11 Pores caused by inclusions of foreign matter Description I II III Numerous, dispersed, isolated or locally concentrated pores or inclusions. Caused by, for example: • vaporization during welding (water, solvent) • contaminated heated tool face Small isolated pores permissible if ∆s < 0.05s Pores and rows of pores permissible if ∆s < 0.10s Pores and rows of pores permissible if ∆s < 0.15s *Classification criteria under scrutiny by DVS. (Continued) 27 AWS G1.10M:2001 Annex A Other Documents (This Annex is not a part of AWS G1.10M:2001, Guide for the Evaluation of Hot Gas, Hot Gas Extrusion, and Heated Tool Butt Thermoplastic Welds, but is included for information purposes only.) A1. DVS (German Welding Society) Recommendations Designation Title DVS 2201-2 Testing of semi-finished products of thermoplastics: Weldability—Test methods—Requirements DVS 2202-1 Imperfections in thermoplastic welded joints—Features, description, evaluation DVS 2203-1 Testing of Welded Joints of Thermoplastics semi-finished products—Test Methods—Requirements DVS 2203-2 Testing of Welded Joints of Thermoplastics materials: Tensile test Designation Title DVS 2205-3 Supplement 3 Calculations of containers and apparatus of thermoplastics, welded joints DVS 2205-4 Supplement 4 Calculation of thermoplastic tanks and apparatuses—Welded flanges, welded collars—Constructive details DVS 2205-5 Calculation of thermoplastic tanks and apparatuses; Rectangular tanks DVS 2207-1 Welding of thermoplastics—Heated tool welding of pipes, pipeline, components and sheets made form PE-HD DVS 2207-3 Hot gas welding of thermoplastic polymers; panels and pipes DVS 2207-3 Supplement Hot gas welding of thermoplastic polymers; panels and pipes; welding parameters for HDPE and PP DVS 2207-11 Welding of thermoplastics—Heated tool welding of pipes, pipeline, components and sheets out of PP DVS 2207-15 Welding of thermoplastics—Heated tool welding of pipes, pipeline, components and sheets out of PVDF DVS 2208-1 Welding of thermoplastics—Machines and devices for the heated tool welding of pipes, pipeline components and sheets DVS 2203-3 Testing of Welded Joints of Thermoplastics; tensile impact test DVS 2203-4 Testing of Welded Joints of Thermoplastics plates and tubes—Tensile creep test DVS 2203-5 Testing of Welded Joints of Thermoplastics plates and tubes—Technological bend test DVS 2205-2 Calculations of thermoplastic tanks and apparatus—Vertical cylindrical non-pressurized tanks DVS 2205-2 Supplement 1 Welded static thermoplastic tanks— Installation inside of buildings DVS 2209-1 Welding of thermoplastics; extrusion welding; procedures, characteristics DVS 2205-2 Supplement 2 Calculation of thermoplastic tanks and apparatus—Vertical cylindrical nonpressurized tanks—Collecting devices DVS 2209-2 Welding of thermoplastics—Hot gas extrusion welding—Requirements for welding machines and tools 29 AWS G1.10M:2001 Designation Title Designation Title DVS 2211 Filler materials of thermoplastics— Scope, designation, requirements, tests DVS 2214 Regulations for the examination of the specialist for plastics welding DVS 2212-1 Examination of plastic welders examination—Group I—Hot Gas welding with torch separate from filler rod (WF), hot gas string-bead welding (WZ), heated tool butt welding (HS) A2. DIN (German) Standards33 Designation Title DIN 1910 Welding—Welding of Plastics; Processes Imperfections in plastic welded joints; Classification, terminology DVS 2212-2 Examination of plastic welders— Examination group II—Hot gas extrusion welding DIN 32 502 DVS 2213 Specialist for Examination 3. DIN is the national standards institution for Germany. DIN is the German equivalent of ANSI. plastics welding— 30 AWS G1.10M:2001 Annex B Document Sources (This Annex is not a part of AWS G1.10M:2001, Guide for the Evaluation of Hot Gas, Hot Gas Extrusion, and Heated Tool Butt Thermoplastic Welds, but is included for information purposes only.) DIN DVS-Verlag GmbH (German Welding Society) Aachener Strasse 172 D-40223 Düsseldorf Germany Telephone: +49/211/15 91-0 American Society for Testing and Materials (ASTM) 100 Barr Harbor Drive West Conshohocken, PA 19428-2959 Telephone: 610-832-9585 American Welding Society (AWS) 550 N.W. LeJeune Road Miami, FL 33126 Telephone: 800-443-9353 31 AWS G1.10M:2001 Annex C Guidelines for Preparation of Technical Inquiries for AWS Technical Committees (This Annex is not a part of AWS G1.10M:2001, Guide for the Evaluation of Hot Gas, Hot Gas Extrusion, and Heated Tool Butt Thermoplastic Welds, but is included for information purposes only.) C1. Introduction provision must be identified in the scope of the inquiry, along with the edition of the standard that contains the provisions or that the Inquirer is addressing. The AWS Board of Directors has adopted a policy whereby all official interpretations of AWS standards will be handled in a formal manner. Under that policy, all interpretations are made by the committee that is responsible for the standard. Official communication concerning an interpretation is through the AWS staff member who works with that committee. The policy requires that all requests for an interpretation be submitted in writing. Such requests will be handled as expeditiously as possible but due to the complexity of the work and the procedures that must be followed, some interpretations may require considerable time. C2.2 Purpose of the Inquiry. The purpose of the inquiry must be stated in this portion of the inquiry. The purpose can be either to obtain an interpretation of a standard requirement, or to request the revision of a particular provision in the standard. C2.3 Content of the Inquiry. The inquiry should be concise, yet complete, to enable the committee to quickly and fully understand the point of the inquiry. Sketches should be used when appropriate and all paragraphs, figures, and tables (or the Annex), which bear on the inquiry must be cited. If the point of the inquiry is to obtain a revision of the standard, the inquiry must provide technical justification for that revision. C2. Procedure C2.4 Proposed Reply. The inquirer should, as a proposed reply, state an interpretation of the provision that is the point of the inquiry, or the wording for a proposed revision, if that is what inquirer seeks. All inquiries must be directed to: Managing Director, Technical Services American Welding Society 550 N.W. LeJeune Road Miami, FL 33126 C3. Interpretation of Provisions of the Standard All inquiries must contain the name, address, and affiliation of the inquirer, and they must provide enough information for the committee to fully understand the point of concern in the inquiry. Where that point is not clearly defined, the inquiry will be returned for clarification. For efficient handling, all inquiries should be typewritten and should also be in the format used here. Interpretations of provisions of the standard are made by the relevant AWS Technical Committee. The secretary of the committee refers all inquiries to the chairman of the particular subcommittee that has jurisdiction over the portion of the standard addressed by the inquiry. The subcommittee reviews the inquiry and the proposed reply to determine what the response to the inquiry should be. Following the subcommittee’s development of the response, the inquiry and the response are presented to the C2.1 Scope. Each inquiry must address one single provision of the standard, unless the point of the inquiry involves two or more interrelated provisions. That 33 AWS G1.10M:2001 entire committee for review and approval. Upon approval by the committee, the interpretation will be an official interpretation of the Society, and the secretary will transmit the response to the inquirer and to the Welding Journal for publication. information that such an interpretation can be obtained only through a written request. The Headquarters staff cannot provide consulting services. The staff can, however, refer a caller to any of those consultants whose names are on file at AWS Headquarters. C4. Publication of Interpretations C6. The AWS Technical Committee All official interpretations will appear in the Welding Journal. The activities of AWS Technical Committees in regard to interpretations, are limited strictly to the interpretation of provisions of standards prepared by the committee or to consideration of revisions to existing provisions on the basis of new data or technology. Neither the committee nor the staff is in a position to offer interpretive or consulting services on: (1) specific engineering problems, or (2) requirements of standards applied to fabrications outside the scope of the document or points not specifically covered by the standard. In such cases, the inquirer should seek assistance from a competent engineer experienced in the particular field of interest. C5. Telephone Inquiries Telephone inquiries to AWS Headquarters concerning AWS standards should be limited to questions of a general nature or to matters directly related to the use of the Standard. The Board of Directors’ policy requires that all AWS staff members respond to a telephone request for an official interpretation of any AWS standard with the 34 AWS G1.10M:2001 AWS List of Documents on Plastics Welding AWS Designation G1.2M/G1.2 Title Specification for Standardized Ultrasonic Welding Test Specimen for Thermoplastics For ordering information, contact Global Engineering Documents, An Information Handling Services Group Company, 15 Inverness Way East, Englewood, Colorado 80112-5776. Telephones: (800) 854-7179, (303) 397-7956; FAX (303) 397-2740; Internet: www.global.ihs.com. 35