1、PUBLISHED DOCUMENT PD CEN ISO/TR 17844:2004 Welding Comparison of standardised methods for the avoidance of cold cracks ICS 25.160.10 PD CEN ISO/TR 17844:2004 This Published Document was published under the authority of the Standards Policy and Strategy Committee on 18 October 2004 BSI 18 October 20
2、04 ISBN 0 580 44575 5 National foreword This Published Document is the official English language version of CEN ISO/TR 17844:2004. The UK participation in its preparation was entrusted to Technical Committee WEE/17, Metal arc welding of steel, which has the responsibility to: A list of organizations
3、 represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence
4、Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself
5、confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and prom
6、ulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the CEN ISO/TR title page, pages 2 to 78, an inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued si
7、nce publication Amd. No. Date CommentsTECHNICALREPORT RAPPORTTECHNIQUE TECHNISCHERBERICHT CENISO/TR17844 September2004 ICS25.160.10 Englishversion WeldingComparisonofstandardisedmethodsforthe avoidanceofcoldcracks(ISO/TR17844:2004) SoudageComparaisondemthodesnormalisespour viterlesfissuresfroid(ISO/
8、TR17844:2004) SchweienVergleichvongenormtenVerfahrenzur VermeidungvonKaltrissen(ISO/TR17844:2004) ThisTechnicalReportwasapprovedbyCENon5December2003.IthasbeendrawnupbytheTechnicalCommitteeCEN/TC121. CENmembersarethenationalstandardsbodiesofAustria,Belgium,Cyprus,CzechRepublic,Denmark,Estonia,Finland
9、,France, Germany,Greece,Hungary,Iceland,Ireland,Italy,Latvia,Lithuania,Luxembourg,Malta,Netherlands,Norway,Poland,Portugal, Slovakia, Slovenia,Spain,Sweden,SwitzerlandandUnitedKingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeS
10、tassart,36B1050Brussels 2004CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.CENISO/TR17844:2004:ECEN ISO/TR 17844:2004 (E) 2 Contents Foreword4 Introduction .5 1 Scope 7 2 CE-method7 2.1 Cracking test method 7 2.2 Parent metal composition range7 2.3 P
11、late thickness and joint geometry .8 2.4 Hydrogen level and welding process 8 2.4.1 Hydrogen scales 8 2.4.2 Selection of hydrogen scales .8 2.5 Heat input .9 2.6 Special considerations13 2.6.1 Conditions which might require more stringent procedures13 2.6.2 Relaxations.14 2.6.3 Simplified conditions
12、 for manual metal-arc welding .14 2.7 Determination of preheat 16 3 CET-method24 3.1 Cracking test method 24 3.2 Parent metal composition range25 3.3 Plate thickness.26 3.4 Hydrogen level and welding process 27 3.5 Heat input .27 3.6 Influence of residual stress 28 3.7 Determination of preheat 28 3.
13、7.1 Calculation of the minimum preheat temperature28 3.7.2 Example for determination : numerical determination of the preheat temperature .29 3.7.3 Example for determination : graphical determination of the preheat temperature 29 3.8 Special considerations31 3.8.1 Reduction of hydrogen content by po
14、st heating (soaking) 31 3.8.2 Welding with reduced preheating 31 3.8.3 Welding with austenitic consumables.31 4 CE N -method 31 4.1 Cracking test method 31 4.2 Parent metal composition range32 4.3 Material thickness33 4.4 Weld metal hydrogen content and welding process33 4.5 Heat input .33 4.6 Weld
15、metal yield strength .34 4.7 Determination of preheat 35 4.8 Special considerations35 4.8.1 Weld metal hydrogen content 35 4.8.2 Number of the weld layers and weld metal strength36 4.8.3 Restraint .36 4.8.4 Weld metal hydrogen cracking.36 5 P cm -method .40 5.1 General40 5.1.1 Cracking test method 4
16、0 5.1.2 HAZ hardness control method .40 5.1.3 Hydrogen controlled method41 5.2 Parent metal composition range41 5.2.1 Hardness controlled method41 5.2.2 Hydrogen controlled method41 CEN ISO/TR 17844:2004 (E) 3 5.2.3 Selection of method 41 5.2.4 Hydrogen controlled method .42 5.3 Plate thickness and
17、joint geometry .42 5.3.1 HAZ hardness controlled method42 5.3.2 Hydrogen controlled method .42 5.4 Hydrogen levels and welding process 43 5.4.1 HAZ hardness controlled method43 5.4.2 Hydrogen controlled method .43 5.5 Energy input.43 5.6 Special considerations44 5.7 Determination of minimum preheat.
18、44 5.7.1 Method according to value of CE.44 5.7.2 HAZ hardness controlled method44 5.7.3 Hydrogen content controlled method .45 Annex A (informative) Comparison of the different methods.54 A.1 General54 A.2 Parent metal composition range54 A.3 Plate thickness and joint geometry .54 A.4 Hydrogen leve
19、ls .55 A.5 Heat input .55 A.6 Prediction comparison55 A.7 Summary and conclusions.56 Annex B (informative) Abbreviations 77 Bibliography78 CEN ISO/TR 17844:2004 (E) 4 Foreword This document CEN ISO/TR 17844:2004 has been prepared by Technical Committee CEN/TC 121 “Welding”, the secretariat of which
20、is held by DIN, in collaboration with Technical Committee ISO/TC 44 “Welding and allied processes”. This document includes a Bibliography. CEN ISO/TR 17844:2004 (E) 5 Introduction The purpose of this document is to compare currently available methods for determining welding procedures for avoiding h
21、ydrogen induced cold cracking during fabrication. This subject has been extensively studied in recent years and many methods of providing guidance on avoidance of cold cracking have been published. These methods vary considerably in how comprehensively the subject has to be treated. It was considere
22、d appropriate to set certain important working criteria for selecting the published methods to be included in this document. In deciding which criteria would be adopted it was agreed that these should include the capabilities for effective use by industry, the end user. Thus the methods should be ab
23、le to be used on the basis of traditionally available information and relevant factors. The agreed list of criteria was set to include the following main input parameters steel composition; welding heat input; joint geometry and material thickness; weld hydrogen level; preheat and in addition graphi
24、cal/computer format of data. Using the above criteria, the following methods were selected. CE (EN 1011-2/ISO/TR 17671-2, C.2-Method A); CET (EN 1011-2/ISO/TR 17671-2, C.3-Method B); CE N (JIS B 8285); P cm(ANSI/AWS D1.1). Each method is considered in a separate clause, under the following headings.
25、 Description of type of test data used to devise the guidelines, e.g. CTS, y-groove, etc; Parent metal composition and range of applicability; Material thickness and range of applicability; Hydrogen level and welding processes; Heat input; Other factors/special considerations; Determination of prehe
26、at (step-by-step example description). An informative Annex compares and contrasts the predictions of the methods in respect of ten different steels and a range of material thickness, joint geometrys, heat inputs and hydrogen levels. CEN ISO/TR 17844:2004 (E) 6 It is important that any calculations
27、using a given method are undertaken using the current edition of the appropriate standard. CEN ISO/TR 17844:2004 (E) 7 1 Scope In addition to EN 1011-2/ISO/TR 17671-2, this document contains further methods for avoidance of cold cracking used by other members of ISO. This document gives guidance for
28、 manual, semi-mechanized, mechanized and automatic arc welding of ferritic steels, excluding ferritic stainless steels, in all product forms. 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
29、2 All used abbreviations in this document are explained in EN 1011-2/ISO/TR 17671-2 and Annex B. 2 CE-method 2.1 Cracking test method This method is based on an original concept of critical hardness to avoid HAZ (heat affected zone) hydrogen cracking. It has been empirically developed incorporating
30、the extensive results of HAZ hardenability studies and cracking tests, the latter mainly but not exclusively being the CTS test type. In its present general format the scheme was originally published in 1973 and, with modifications and updates, has been continuously incorporated in British Standards
31、 for nearly 25 years. The experience of its use, both in the UK and elsewhere, has been extremely satisfactory. 2.2 Parent metal composition range The parent metals covered are carbon, carbon manganese, fine grained and low alloyed steels (groups 1 to 3 of CR ISO 15608:2000). The steels that were us
32、ed over many years to develop the method have covered a wide range of compositions and it is believed that they are adequately represented by Table 1. Table 1 Range of chemical composition of the main constituents for parent metal for CE-method Element Percentage by weight Carbon 0,05 0,25 Silicon 0
33、,8 Manganese 1,7 Chromium 0,9 Copper 1,0 Nickel 2,5 Molybdenum 0,75 Vanadium 0,20 Carbon equivalent values (in %) for parent metals are calculated using the following equation (1): CEN ISO/TR 17844:2004 (E) 8 15 5 6 Cu Ni V Mo Cr Mn C CE IIW + + + + + + = (1) and are applicable to steels with carbon
34、 equivalents in the range CE = 0,30 % to 0,70 %. If of the elements in this formula only carbon and manganese are stated on the mill sheet for carbon and carbon manganese steels, then 0,03 % should be added to the calculated value to allow for residual elements and impurities. Where steels of differ
35、ent carbon equivalents or grades are to be joined, the higher carbon equivalent value should be used. This carbon equivalent formula may not be suitable for boron containing steels. 2.3 Plate thickness and joint geometry The influence of plate thickness and joint geometry is determined by calculatin
36、g the combined thickness. This should be determined as the sum of the parent metal thickness averaged over a distance of 75 mm from the weld centre line (see Figure 1). Combined thickness is used to assess the heat sink of a joint for the purpose of determining the cooling rate. If the thickness inc
37、reases greatly beyond 75 mm from the weld centre line, it may be necessary to use a higher combined thickness value. Steels with thicknesses, t, in the range 6 mm t 100 mm were used in the tests to develop the scheme. 2.4 Hydrogen level and welding process 2.4.1 Hydrogen scales The hydrogen scales t
38、o be used for any arc welding process depend principally on the weld diffusible hydrogen content (according to EN ISO 3690) and should be as given in Table 2. Table 2 Hydrogen scales Diffusible hydrogen content (ml/100 g deposited material) Hydrogen scale 15 A 10 15 B 5 10 C 3 5 D 3 E Data from a wi
39、de range of arc welding processes has been used in developing the scheme and these include manual metal arc (111), gas metal arc with solid wire (131, 135) and tubular wire (136, 137), the latter of both gas shielded and self shielded types, and submerged arc welding (121). NOTE The numbers in brack
40、ets are process numbers according to EN ISO 4063. 2.4.2 Selection of hydrogen scales The following is general guidance on the selection of the appropriate hydrogen scale for various welding processes. CEN ISO/TR 17844:2004 (E) 9 Manual metal arc welding with basic covered electrodes can be used with
41、 the scale B to D depending on the electrode manufacturers/suppliers classification of the consumable. Manual metal arc welding with rutile or cellulosic electrodes should be used with scale A. Flux cored or metal cored consumables can be used with scales B to D depending on the manufacturers/suppli
42、ers classification of the wire electrodes. Submerged arc welding with one wire electrode (121) and flux consumable combinations can have hydrogen levels appropriate to scales B to D, although most typically these will be scale C but therefore need assessing for each named product combination and con
43、dition. Submerged arc fluxes can be classified by the manufacture/supplier but this does not necessarily confirm that a practical flux wire combination also meets the same classification. Solid wire electrodes for gas-shielded arc welding (131, 135) and for TIG welding (141) may be used with scale D
44、 unless specifically assessed and shown to meet scale E. Scale E may also be found to be appropriate for some cored wires (136, 137) and some manual metal arc covered electrodes, but only after specific assessment. In achieving these low levels of hydrogen consideration should be given to the contri
45、bution of hydrogen from the shielding gas composition and atmospheric humidity. For plasma arc welding (15), specific assessment should be made. NOTE The numbers in brackets are process numbers according to EN ISO 4063. 2.5 Heat input Heat input values (in kJ/mm) for use with Figure 2 a) to m) shoul
46、d be calculated in accordance with EN 1011-1/ ISO/TR 17671-1 and EN 1011-2/ISO/TR 17671-2. For manual metal-arc welding, heat input values are expressed in Tables 3 to 6 in terms of electrode size and weld run lengths. The details given in Tables 3 to 6 relate to electrodes having an original length
47、 of 450 mm. For other electrode lengths the following equation (2) may be used: Runlength mm Electrodediameter L F Heatinput () () = 2(2) where L is the consumed length of the electrode (in mm) (normally the original length of 450 mm less 40 mm for stub end); F is a factor (in kJ/mm 3 ) having a val
48、ue depending on the electrode efficiency, as follows: efficiency approximately 95 % F = 0,0368 95 % 130% F = 0,0608 CEN ISO/TR 17844:2004 (E) 10 Table 3 Run length for manual metal-arc welding 95 % electrode efficiency, approximately Run length from 410 mm of a 450 mm electrode of diameter 2,5 3,2 4,0 5,0 6,0 6,3 Heat input kJ/mm mm mm mm mm mm mm 0,8 120 195 300 470 1,0 95 155 240 375 545 600 1,2 130 200 315 450 500 1,4 110 170 270 390 430 1,6 95 150 235 340 375 1,8 85 135 210 300 335 2,0 120 190 270 300 2,2 110 170 245 270 2,5 95 150 215 240 3,0 80 125 180 200 3,5 110 15
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