1、AWS D14.8M:2009(ISO/TR 17844:2004 IDT)An American National StandardStandard Methodsfor the Avoidanceof Cold Cracks550 N.W. LeJeune Road, Miami, FL 33126AWS D14.8M:2009 (ISO/TR 17844:2004 IDT)An American National StandardApproved by theAmerican National Standards InstituteNovember 11, 2008Standard Me
2、thods for theAvoidance of Cold Cracks1st EditionPrepared by theAmerican Welding Society (AWS) D14 Committee on Machinery and EquipmentUnder the Direction of theAWS Technical Activities CommitteeApproved by theAWS Board of DirectorsAbstractThis is the U.S. national adoption of ISO 17844:2004, Welding
3、 Comparison of standardized methods for theavoidance of cold cracks.iiAWS D14.8M:2009 (ISO/TR 17844:2004 IDT)International Standard Book Number: 978-0-87171-668-2American Welding Society550 N.W. LeJeune Road, Miami, FL 33126 2009 by American Welding SocietyAll rights reservedPrinted in the United St
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6、-8400; Internet:.iiiAWS D14.8M:2009 (ISO/TR 17844:2004 IDT)Statement on the Use of American Welding Society StandardsAll standards (codes, specifications, recommended practices, methods, classifications, and guides) of the AmericanWelding Society (AWS) are voluntary consensus standards that have bee
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23、ety, 550 N.W. LeJeune Road, Miami, FL 33126.This page is intentionally blank.ivAWS D14.8M:2009 (ISO/TR 17844:2004 IDT)vAWS D14.8M:2009 (ISO/TR 17844:2004 IDT)PersonnelAWS D14 Committee on Machinery and EquipmentJ. L. Warren, Chair CNH America, LLCL. L. Schweinegruber, Vice Chair Robinson Industries,
24、 IncorporatedM. Rubin, Secretary American Welding SocietyD. B. Ashley Hartford Steam Boiler Inspection and Insurance CompanyB. K. Banzhaf CNH America, LLCJ. E. Campbell WeldTech Solutions CorporationD. J. Landon Vermeer Manufacturing CorporationT. J. Landon Chicago Bridge (2) CET (EN 1011-2/ISO/TR 1
25、7671-2, C.3-Method B);(3) CEN(JIS B 8285); and(4) Pcm(AWS D1.1).Each method is considered in a separate clause, under the following headings:(1) Description of type of test data used to devise the guidelines, e.g., CTS, y-groove, etc.;(2) Parent metal composition and range of applicability;(3) Mater
26、ial thickness and range of applicability;(4) Hydrogen level and welding processes;(5) Heat input;(6) Other factors/special considerations; and(7) Determination of preheat (step-by-step example description).viiiAWS D14.8M:2009 (ISO/TR 17844:2004 IDT)An informative annex compares and contrasts the pre
27、dictions of the methods in respect of ten different steels and a rangeof material thickness, joint geometries, heat inputs, and hydrogen levels.It is important that any calculations using a given method are undertaken using the current edition of the appropriatestandard.Comments and suggestions for
28、the improvement of this standard are welcome. They should be sent to the Secretary,AWS D14 Committee on Machinery and Equipment, American Welding Society, 550 N.W. LeJeune Road, Miami, FL33126.ixAWS D14.8M:2009 (ISO/TR 17844:2004 IDT)Table of ContentsPage No.Personnel vForeword.viiList of Tables.xLi
29、st of Figuresxi1. Scope.12. CE-method .12.1 Cracking test method .12.2 Parent metal composition range.12.3 Plate thickness and joint geometry 22.4 Hydrogen level and welding process .22.5 Heat input.32.6 Special considerations .72.7 Determination of preheat .93. CET-method .173.1 Cracking test metho
30、d .173.2 Parent metal composition range.183.3 Plate thickness .193.4 Hydrogen level and welding process .203.5 Heat input.203.6 Influence of residual stress 213.7 Determination of preheat .213.8 Special considerations .244. CEN-method .244.1 Cracking test method .244.2 Parent metal composition range
31、.244.3 Material thickness254.4 Weld metal hydrogen content and welding process.254.5 Heat input.264.6 Weld metal yield strength 264.7 Determination of preheat .274.8 Special considerations .275. Pcm-method.325.1 General.325.2 Parent metal composition range.335.3 Plate thickness and joint geometry 34
32、5.4 Hydrogen levels and welding process .345.5 Energy input.355.6 Special considerations .365.7 Determination of minimum preheat.36Annex A (informative) Comparison of the different methods .47Annex B (informative) Abbreviations 73Bibliography.74National Informative Annexes75Annex C (Informative)Guid
33、elines for the Preparation of Technical Inquiries .75Index .77xAWS D14.8M:2009 (ISO/TR 17844:2004 IDT)List of TablesTable Page No.1 Range of chemical composition of the main constituents for parent metal for CE-method.12 Hydrogen scales23 Run length for shielded metal arc welding 95 % electrode effi
34、ciency, approximately .44 Run length for shielded metal arc welding 95 % 130 %.77 Values for heat input for shielded metal arc welding of single run fillet welds .88 Steps for the determination of preheat99 Range of chemical composition of the main constituents for parent metal for the CET-method.18
35、10 Range of validity.1811 Steel with the following chemical composition in % by weight 2212 Steps for determination.2313 Range of chemical composition of main constituents for parent metal for CENmethod.2414 Value of coefficient f(C).2515 Yield strength levels for all-weld-metal2616 Steps for the de
36、termination of preheat2717 Welding process designations and terminology3518 Multiplication factors relating to welding processes3519 Steps of the method 3620 Steps of the method 3721 Steps of the method 3722 Susceptibility index grouping as function of hydrogen content level HD and compositionparame
37、ter Pcm4423 Minimum preheat and interpass temperature for three levels of restraint 45A.1 Parent metal composition range47A.2 Steels used for comparing predicted preheats 50A.3 Comparison of preheat temperature according to different methods (plate thickness 25 mm)51A.4 Comparison of preheat tempera
38、ture according to different methods (plate thickness 50 mm)53A.5 Comparison of minimum preheat temperature (hydrogen level of 13.6 ml/100 g)55xiAWS D14.8M:2009 (ISO/TR 17844:2004 IDT)List of FiguresFigure Page No.1 Examples for determination of combined thickness.102 Conditions for welding with defi
39、ned carbon equivalents .113 Preheat temperature in relation to CET 194 Preheat temperature in relation to the plate thickness 195 Preheat temperature in relation to hydrogen content, HD 206 Preheat temperature in relation to heat input, Q.217 Graphical method for the determination of minimum preheat
40、 temperature.238 Master curves for minimum preheat for y-groove cracking test 299CENcorrection with respect to weld heat input and CEIIW.3010 CENcorrection with respect to weld metal hydrogen content (DM is deposited metal) 3111 Correction of necessary preheat of welding practice3212 Critical coolin
41、g rate for 350 HV and 400 HV 3813 Zone classification of steels3814 Relationship between fillet weld size and energy input .3915 Graphs to determine cooling rates for single-pass submerged arc fillet welds 40A.1 Comparison of preheat temperature Toaccording to CE- and CET-methods; plate thickness 25
42、 mm .59A.2 Comparison of preheat temperature Toaccording to CEN- and CET-methods; plate thickness 25 mm .62A.3 Comparison of preheat temperature Toaccording to Pcm- and CET-methods; plate thickness 25 mm 63A.4 Comparison of preheat temperature Toaccording to CE- and CEN-methods; plate thickness 25 m
43、m.64A.5 Comparison of preheat temperature Toaccording to CE- and Pcm-methods; plate thickness 25 mm 65A.6 Comparison of preheat temperature Toaccording to Pcm- and CEN-methods; plate thickness 25 mm66A.7 Comparison of preheat temperature Toaccording to CE- and CET-methods; plate thickness 50 mm .67A
44、.8 Comparison of preheat temperature Toaccording to CEN- and CET-methods; plate thickness 50 mm .68A.9 Comparison of preheat temperature Toaccording to Pcm- and CET-methods; plate thickness 50 mm 69A.10 Comparison of preheat temperature Toaccording to CE- and CEN-methods; plate thickness 50 mm.70A.1
45、1 Comparison of preheat temperature Toaccording to CE- and Pcm-methods; plate thickness 50 mm 71A.12 Comparison of preheat temperature Toaccording to Pcm- and CEN-methods; plate thickness 50 mm72This page is intentionally blank.xiiAWS D14.8M:2009 (ISO/TR 17844:2004 IDT)AWS D14.8M:2009 (ISO/TR 17844:
46、2004 IDT)1Welding Comparison of standardized methods for the avoidance of cold cracks1 ScopeIn addition to EN 1011-2/ISO/TR 17671-2, this document contains further methods for avoidance of coldcracking used by other members of ISO. This document gives guidance for manual, semi-mechanized,mechanized
47、and automatic arc welding of ferritic steels, excluding ferritic stainless steels, in all productforms.Further information about the materials and process parameters is given in Clauses 2 to 5.NOTE 1 All references are listed in the annex “Bibliography.”NOTE 2 All used abbreviations in this document
48、 are explained in EN 1011-2/ISO/TR 17671-2, and Annex B.2 CE-method2.1 Cracking test methodThis method is based on an original concept of critical hardness to avoid HAZ (heat-affected zone)hydrogen cracking. It has been empirically developed incorporating the extensive results of HAZhardenability st
49、udies and cracking tests, the latter mainly but not exclusively being the CTS test type. In itspresent general format the scheme was originally published in 1973 and, with modifications and updates,has been continuously incorporated in British Standards for nearly 25 years. The experience of its use,both in the UK and elsewhere, has been extremely satisfactory.2.2 Parent metal composition rangeThe parent metals covered are carbon, carbon manganese, fine grained and low alloyed steels (groups 1to 3 of CR ISO 15608:2000).The steels that were used over many years to develop the method
