Pwhtn 29 Iso Dtr 14745-Welding

© ISO 2007 – All rights reservedISO/TC 44/SC 10/WG 8 N 29 Supersedes N 26R Date: 2011-09-14 ISO/dTR 14745 ISO/TC 44/SC 10/WG 8 Secretariat: SFS Welding – Post weld heat treatment parameters for steels Soudage — Lignes directrices concernant les exigences de qualité relatives au traitement thermique en soudage et techniques connexes Warning This document is not an ISO International Standard. It is distributed for review and comment. It is subject to change without notice and may not be referred to as an International Standard. Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to provide supporting documentation. Document type: International Standard Document subtype: Document stage: (40) Enquiry Document language: E /opt/scribd/conversion/tmp/scratch6208/76257551.doc STD Version 2.2 + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyright@iso. electronic. Requests for permission to reproduce should be addressed to either ISO at the address below or ISO's member body in the country of the requester. stored in a retrieval system or transmitted in any form or by any means. recording or otherwise.iso. without prior written permission being secured. Violators may be prosecuted. neither this ISO draft nor any extract from it may be reproduced. Except as permitted under the applicable laws of the user's country.org Web www. II © ISO 2007 – All rights reserved .org Reproduction may be subject to royalty payments or a licensing agreement. photocopying.ISO/NP 14745 Copyright notice This ISO document is a Draft International Standard and is copyright-protected by ISO. ISO copyright office Case postale 56 • CH-1211 Geneva 20 Tel. ........1 Normative references...............................3 7 Application of PWHT...2 5 General information..9 8 Dissimilar ferritic joints.......................................................................3 6 Heat treatment conditions.............................ISO/NP 14745 Contents Foreword........................................................................................................................................................................................2 Terms and definitions..............................................................................................10 Page © ISO 2007 – All rights reserved III .............................................................................................................................................................................................................iv 1 2 3 Scope....................................................................................................................................................................................................................................................................................................................................................................................... Requests for official interpretations of technical aspects of this International Standard should be directed to the Secretariat of ISO/TC 44/SC 10 via your national standards body. Part 2. Subcommittee SC 10.iso. in liaison with ISO. also take part in the work. Welding in collaboration. ISO shall not be held responsible for identifying any or all such patent rights. International organizations. The work of preparing International Standards is normally carried out through ISO technical committees. ISO/TR 14745 was prepared by Technical Committee ISO/TC 44. a listing of these bodies can be found at www. Welding and allied processes. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives. The main task of technical committees is to prepare International Standards. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee.ISO/NP 14745 Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). IV © ISO 2007 – All rights reserved .org. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. governmental and non-governmental. and by Technical Committee CEN/TC 121. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. The recommendations do not supersede any guidance from the material supplier specifications.DRAFT INTERNATIONAL STANDARD ISO/NP 14745 Welding – Post weld heat treatment parameters for steels 1 Scope This Technical Report provides recommendations for post weld heat treatment (PWHT) of steels with recommendations for holding temperatures and holding times for different materials and material thicknesses. These recommendations are limited to stress relieving and independent of type of product or location. g. This Technical Report does not specify when PWHT is required. © ISO 2007 – All rights reserved 1 . Such requirements are given in product standards. e. thermomechanically treated fine-grain steels. material specifications or material data sheets. in mm normalized and tempered quenched and tempered Hollomon-Jaffe Parameter post weld heat treatment PWHT 2 © ISO 2007 – All rights reserved . Quality requirements for heat treatment in connection with welding and allied processes EN 10052. ISO 17663. Welding — Guidelines for a metallic materials grouping system 3 Terms and definitions For the purposes of this document.2 heating rate variation in temperature as a function of time during heating [ISO 4885] 3. 3. the terms and definitions given in EN 10052 and the following apply. only the edition cited applies. For dated references. 4 e NT QT P Symbols and abbreviations material thickness. NOTE 2 Normally the holding temperature is expressed as a temperature range. 3. material and material thickness.1 cooling rate variation in temperature as a function of time during cooling [ISO 4885] 3. type of material and material thickness.4 holding time time the product or component is kept in the holding temperature NOTE 1 The holding time starts when the temperature in all measuring points has reached the minimum value of the range of the holding temperature and stops when one of the measuring points falls below that temperature. Vocabulary of heat treatment terms for ferrous products ISO/TR 15608. NOTE 2 The holding time depends on the type of heat treatment.ISO/NP 14745 2 Normative references The following referenced documents are indispensable for the application of this document. the latest edition of the referenced document (including any amendments) applies.3 holding temperature temperature in which the product or component is kept in order to achieve specified properties NOTE 1 The holding temperature depends on the type of heat treatment. For undated references. This effect is explained and published as Hollomon-Jaffe Parameter P as given in equation (1): P = Ts (20 + lg t)10.3 where Ts t is the holding temperature. f) for fillet welded attachments the thickness of the weld. b) for butt welded set-on nozzles the thickness of the nozzle c) for fillet welded set-on nozzles the thickness of the weld. It shall permit the temperature control of the component with adequate accuracy and uniformity especially for materials having a small temperature range. the heating. tensile strength and toughness of the material. is the holding time. Where welded joints are connecting parts different in thickness. Equipment used for the heat treatment shall be suitable according to ISO 17663. The heat treatment of products or components shall be recorded by the manufacturer indicating the holding temperature. is considered necessary. g. If PWHT of materials. 6 Heat treatment conditions Post weld heat treatment. (1) A higher PWHT temperature than tempering temperature for NT. the PWHT holding time and holding temperature shall take into account recommendations from the material manufacturer as well as the welding consumable manufacturer to achieve the required material properties. NOTE PWHT may be carried out on steels of thickness lower than specified by Table 1. e) for set-in nozzles the thickness of the weld. the thickness to be used in applying the requirements for post weld heat treatment shall be: a) for butt welds the thicker of the two parts.ISO/NP 14745 R NOTE inner radius Alternative symbols may be used in other standards 5 General information PWHT shall be performed in accordance with a written heat treatment procedure specification which includes the essential parameters for the heat treatment process. with the exception of those materials mentioned in clause 8. e. The additional effect of multiple heating cycles should be considered. in hours.and cooling-rate. holding time. Heat treatment as per Table 1 particularity in the upper range of holding temperature and/or holding time may unduly impair the physical properties. in Kelvin. shall be applied to steels in accordance with Table 1 on completion of welding.and QT-materials could impair the mechanical properties of the material. Such instances will include products intended for service with media liable to cause stress corrosion cracking or prevention of brittle fracture. not listed in Table 1. d) for set-through nozzles the thickness of the shell. yield strength. © ISO 2007 – All rights reserved 3 . 18MnMo4-5.1 Quenched and tempered steels with ReH > 690 MPa Low vanadium alloyed Cr-Mo-(Ni) steels with Mo ≤ 0. a further heat treatment is normally carried out.5 17.1 Normalized fine grain steels with ReH > 360 MPa Thermomechanically treated fine grain steels with 360 MPa< ReH ≤ 460 MPa Thermomechanically treated fine grain steels with ReH > 460 MPa Quenched and tempered steels with ReH > 360 ≤ 690 MPa • • • • 15NiCuMoNb5-6-4 +NT or +QT 20MnMoNi4-5 3) 360 MPa < ReH ≤ 500 MPa1) 500 MPa < ReH ≤ 690 MPa 580-620 2) e ≤ 15 30 2e 120 17. In Table 1 a Pcrit-value is introduced. The thickness to be used in defining the holding time required at temperature shall be the thickness of the weld applied after the PWHT.5 delivery condition M delivery condition QT delivery condition N (except 16Mo3) 16Mo3.3 2. This parameter.5 e ≤ 35 1) 35 < e ≤ 90 e > 90 30 e–5 40 + 0.3 17.1 % and Cr ≤ 0.2 Steels with 275 MPa < ReH ≤ 360 MPa • • • • Material thickness e Holding time (min) Pcrit (see Clause 6) 30 e–5 40 + 0.5 - 550-620 2) 15 < e ≤ 60 530-580 2) e > 60 4) 3.5e 17.7% 4) 4 © ISO 2007 – All rights reserved .3 % and Ni ≤ 0. 18Mo5 530-580 550-600 2) 550-600 550-620 530-580 530-580 4) 17.3 17. a critical Hollomon-Jaffe value.2 4. shall not be exceeded without proving the mechanical properties.1 Steels with ReH ≤ 275 MPa Material Holding temperature (°C) (mm) 1) 550-600 e ≤ 35 1) 35 < e ≤ 90 e > 90 1.7 % and V ≤ 0. Table 1 Post weld heat treatment parameters for steel Material Group ISO/TR 15608 1.2 3.ISO/NP 14745 When additional welds or weld repairs have been made after post weld heat treatment.3 1.1 2.5e 17.5 17.5 17. 4 % < Mo ≤ 0.6e 19.2 % and free of V 6) • 10CrMo9-10.2 Cr-Mo-steels with 1. 60 40 + e 5.7 % and Ni ≤ 1.5 % < Cr ≤ 7 % and 0.7 • • 13CrMo4-5 All others 630-700 620–680 7) e > 60 18.75 % < Cr ≤ 1.7% < Mo ≤ 1.5 5.1 % and Cr ≤ 0.3 5.5 © ISO 2007 – All rights reserved 5 . 26CrMo4-2 13CrMoSi5-5 620–680 2) 5) e ≤ 15 15 < e ≤ 60 30 2e 60 + e 18. X12CrMo5 680-750 e ≤ 15 30 19.7 % and free of V 1) • • 25CrMo4. 11CrMo9-10 8) 670-730 660-720 2) e ≤ 15 15 < e ≤ 60 30 2e 60 + e 2.7 % and V ≤ 0.4e 225 + 0.7 % and free of V • X11CrMo5.5 % and 0. min.5% 15NiCuMoNb5-6-4 550–620 e ≤ 20 20 < e ≤ 35 35 < e ≤ 90 e > 90 30 60 e.2 • e > 60 • 12CrMo9-10 660-720 2) 9) e ≤ 125 e > 125 19.5 % and Mo ≤ 0.ISO/NP 14745 Material Group ISO/TR 15608 • Material Holding temperature (°C) Material thickness e (mm) 1) Holding time (min) Pcrit (see Clause 6) 18MnMoNi5-5 580-640 2) e ≤ 15 3) 15 < e ≤ 60 e > 60 30 2e 120 - • 15MnCrMoNiV5-3 4) 4.1 Cr-Mo-steels with 0.3 Cr-Mo-steels with 3.2 Low vanadium alloyed Cr-Mo-(Ni) steels with Mo ≤ 0.5 % < Cr ≤ 3. 75 % and Mo ≤ 0.7 % < Mo ≤ 1.1 High vanadium Cr-Mo-(Ni) with 0.35 % 680-730 all - 6 © ISO 2007 – All rights reserved .3 % < Cr ≤ 0.4 Cr-Mo-steels with 7 % ≤ Cr ≤ 10 % and 0. 180 - 5.ISO/NP 14745 Material Group ISO/TR 15608 • Material Holding temperature (°C) Material thickness e (mm) 1) Holding time (min) Pcrit (see Clause 6) X16CrMo5-1 700-750 15 < e ≤ 60 e > 60 2e 60 + e 30 2.2 % and free of V 740-780 e ≤ 12 12 < e ≤ 60 e > 60 - 6.5e 90 + e 90 + e. min.7 % and V ≤ 0. 0% < Cr ≤ 10 % and 0.2 High vanadium Cr-Mo-(Ni) with 0.5e - 9.5 % and 0.1 10. min 60 30 2.55 % High vanadium Cr-Mo-(Ni) with 7.0 % < Ni ≤ 10 % Austenitic ferritic stainless steels with Cr ≤ 24 % 5) Generally not applicable 4) Austenitic ferritic stainless steels with Cr > 24 % © ISO 2007 – All rights reserved 7 .2 9.4 High vanadium Cr-Mo-(Ni) with 3.0 % Ni alloyed steels with 3.7 % < Mo ≤ 1.3 6.ISO/NP 14745 Material Group ISO/TR 15608 6.0 % and Mo ≤ 0.5 % ≤ Cr ≤ 30% • X3CrNi13-4 530–570 all 240 - 8.1 8.35 % and 10.4e 19.45 % < V ≤ 0.7 % and 0.0 % < Ni ≤ 8.35 % • • Material Holding temperature (°C) Material thickness e (mm) 1) Holding time (min) Pcrit (see Clause 6) 12CrMoV12-10 13CrMoV9-10 e ≤ 125 690–710 2) e > 125 4) 2.0 % 2) 11) 530–580 e ≤ 35 1) 35 < e ≤ 90 e > 90 30 e–5 40 + 0.2 Ni alloyed steels with 8.2 Martensitic stainless steels with C ≤ 0.2 % • X10CrMoVNb9-1 730–770 10) e ≤ 30 30 < e ≤ 60 e > 60 60 120 2e 2e.3 10.2 Austenitic stainless steels with Cr ≤ 19 % Generally not applicable 4) Austenitic stainless steels with Cr > 19 % Ni alloyed steels with Ni ≤ 3.1 9.4 225 + 0.2 % and V ≤ 0.5 • • • • X10CrWMoVNb9-2 X20CrMoV11-1 X20CrMoNiV 11-1 X20CrMoV12-1 740–770 10) 730–770 10) all e ≤ 12 12 < e ≤ 60 e > 60 - 7.5e 90 + e 20.7 % < Mo ≤ 1.75 % < Cr ≤ 3.5 % < Cr ≤ 7.6e 6. If PWHT is considered necessary. For thickness ≤ 15 mm PWHT is optional.3 mm. – nominal wall thickness ≤ 7. to reduce the danger of stress corrosion cracking or hydrogen-induced cracking (sour gas)). According to EN 13480-4 no post weld heat treatment is required if all the following conditions are fulfilled: – tubes with outside diameter ≤ 114. without new heat treatment. in view of possible carbon diffusion PWHT should be avoided. After the welding of the 3.1 mm – minimum pre-heating temperature 200 °C 2) 3) 4) 5) 6) 7) According to EN 13445-4 no post weld heat treatment is required if all the following conditions are fulfilled: – tubes with nominal diameter < 120 mm.ISO/NP 14745 Note 1) Text For thickness ≤ 35 mm post weld heat treatment is normally only necessary in special cases (e. Higher temperatures may be applied subject to conditions given in application standards. – nominal wall thickness < 13 mm 8) According to EN 13445-4 no post weld heat treatment required if all the following conditions are fulfilled: – tubes with nominal diameter < 120 mm – nominal wall thickness < 13 mm – design temperature > 480 °C 9) In case of intermediate stress relieving (ISR): 630–650°C Intermediate cooling of the weld below the Mf temperature (typically 90-100 °C) shall take place before PWHT to ensure full transformation into martensite. Normally welded with austenitic filler metal. 10) 11) 8 © ISO 2007 – All rights reserved . – a preheat temperature of minimum 100°C is applied during the welding operation. it is permitted to weld. components that are not subject to pressure provided the following conditions are met: – the weld dimensions (weld thickness or corner joint throat) are less or equal to 12 mm.5 % Ni steels with a thickness over 35 mm. the PWHT holding time and holding temperature shall take into account recommendations from the material manufacturer as well as the welding consumable manufacturer to achieve the required material properties.g. for temperatures up to 500 °C variation in temperature throughout the product or component shall not exceed 150 °C within 4 500 mm and the temperature gradient shall be gradual. © ISO 2007 – All rights reserved 9 . When the product or component has attained a uniform holding temperature (see Table 1) this temperature shall be held for the period specified in Table 1. The PWHT temperatures and times shall be in accordance with Table 1. During the heating and holding periods. The rate for heating or cooling of the product or component shall not exceed the following:    for thickness e ≤ 25 mm: for thickness 25 mm < e ≤ 100 mm: for thickness e > 100 mm : 220 K/h. the temperature of the furnace at the time when the product or component is placed in or taken out of the furnace shall not exceed:   400 °C for products or components of not complicated shape or e < 60 mm thickness. Above 500 °C. 7.ISO/NP 14745 7 Application of PWHT 7. (5 500/e) K/h. 7. this variation shall not exceed 100 °C. There shall be no direct impingement of flame on the product or component. 55 K/h. Materials other than those listed in Table 1 shall be heat treated according to the specification of the material manufacturer.2 Heating and cooling During the heating and cooling periods.. The temperature specified shall be the actual temperature of any part of the product or zone being heat treated. the furnace atmosphere shall be controlled so as to avoid excessive oxidation of the surface of the product or component.3 Heating in a furnace In the case of furnace PWHT.1 General PWHT can be applied with a furnace or with local heating. Reference should be made to ISO 17663 for the methods of application. 300 °C for products or components of complicated shape or e ≥ 60 mm thickness. 3 Dissimilar parts Where a weld is between a structural part and a pressure part the PWHT should be as for the pressure part. e. Consideration shall be given to the effect of this higher temperature and possibly longer time on the mechanical properties of the second material in accordance with the requirements stated in application standards.ISO/NP 14745 8 Dissimilar ferritic joints 8. This shall include the effect of PWHT on impact values and microstructure in addition to strength. In this respect the time shall be measured when the lowest reading thermocouple reaches a temperature 10 °C below the minimum specified in Table 1 (without the need for requalification of the welding procedure). EXAMPLE First weld X11CrMo9-1 to 10CrMo9-10 and PWHT at (730 to 750) °C.g. When the maximum temperature allowed in Table 1 of one material in the dissimilar combination is lower than the minimum temperature allowed for the second. then PWHT for the material with the highest temperature in Table 1 shall be carried out. PWHT each component separately after welding at the appropriate time and temperature for each material in the combination.1 General Where a product is manufactured from dissimilar ferritic steels special consideration with respect to the influence on the mechanical properties shall be given to the post weld heat treatment. c) Weld overlay the joint preparations with stainless steel or high nickel weld metal.2 Holding temperature If the maximum temperature in Table 1 required of one material in the dissimilar combination is equal to or greater than the minimum of the second. 8. then later weld 10CrMo9-10 to 13CrMo4-5 and PWHT at (670 to 690) °C. Weld the component/material combination of the weld overlay joints using stainless/high nickel weld and do not carry out further PWHT. 8.g. 10 © ISO 2007 – All rights reserved . but as close to the minimum temperature as practical. e. 16Mo3 to 13CrMo4-5. b) redesign the combination to include a transition material that overlaps the temperature range. 13CrMo4-5 to X11CrMo9-1 then one of the following routes shall be followed: a) PWHT the combination in accordance with the requirements for the material requiring the highest temperature according to Table 1 and carry out a simulated treatment on the other material to determine suitable mechanical properties for design.