BS-6223-1990.pdf

BRITISH STANDARD BS 6223:1990 Specification for Friction welding of joints in metals Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 06:18:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6223:1990 This British Standard, having been prepared under the direction of the Welding Standards Policy Committee, was published under the authority of the Board of BSI and comes into effect on 31 January 1991 © BSI 06-1999 The following BSI references relate to the work on this standard: Committee reference WEE/41 Draft for comment 89/72470 DC ISBN 0 580 18758 6 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Welding Standards Policy Committee (WEE/-) to Technical Committee WEE/41, upon which the following bodies were represented: Associated Offices Technical Committee Association of Manufacturers Allied to the Electrical and Electronic Industry (BEAMA Ltd.) British Gas plc British Steel Industry Imperial Chemical Industries Ltd. Society of British Aerospace Companies Ltd. Society of Motor Manufacturers and Traders Ltd. The Welding Institute Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 06:18:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6223:1990 © BSI 06-1999i Contents Page Committees responsible Inside front cover Foreword iii 1 Scope 1 2 Definitions 1 3 Information and requirements to be agreed and to be documented 2 3.1 Information to be supplied by the purchaser 2 3.2 Requirements to be agreed 2 4 Parent metal 4 5 Cross-sectional area of the joint 4 6 Preparation of faying surfaces 4 7 Work holding 4 7.1 Alignment 4 7.2 Overhang 4 7.3 Clamping force 4 8 Welding variables 5 9 Post-weld heat treatment 5 10 Procedure approval tests 5 10.1 General 5 10.2 Number of tests 5 10.3 Changes affecting approval 5 10.4 Heat treatment and upset removal 5 10.5 Test requirements 5 10.6 Test specimens 5 10.7 Test procedures 7 10.8 Acceptance criteria 8 11 Production quality control 10 11.1 General 10 11.2 Methods of control 11 12 Weldment inspection 11 Appendix A Equipment 13 Appendix B Welding variables 13 Appendix C Procedure sheet information for friction welding 15 Appendix D Additional tests 15 Appendix E Types of weld imperfections 16 Figure 1 Classification of friction welding processes 3 Figure 2 Preparation of specimens for bend testing joints between solid components 6 Figure 3 Specimens for bend testing joints between hollow components and solid or plate components 7 Figure 4 Bend tests for conventional friction welding 9 Figure 5 Bend tests for radial friction welding 12 Figure 6 Generalized diagram of speed, applied force and axial movement with time for continuous drive friction welding 13 Figure 7 Generalized diagram of speed, applied force and axial movement with time for stored energy friction welding 16 Figure 8 Example of lack-of-bond defects 17 Figure 9 Example of overheating in the heat affected zone and lack-of-bond defects at periphery 17 Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 06:18:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6223:1990 ii © BSI 06-1999 Page Figure 10 Example of lack-of-bond defects and inclusions revealed by tensile test 17 Figure 11 Example of inclusion revealed as a result of bend test 18 Figure 12 Example of weld zone cracks produced by cold cracking 18 Figure 13 Example of brittle intermetallic compound layers at dissimilar metal friction weld interface 18 Figure 14 Sketch to show bulging 19 Table 1 Bend diameter for selected material8 Table 2 Location of specimens for bend test excluding those for radial friction welding 8 Table 3 Location of specimens for bend test for radial friction welding 8 Publication(s) referred to Inside back cover Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 06:18:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6223:1990 © BSI 06-1999iii Foreword This British Standard, which has been prepared under the direction of the Welding Standards Policy Committee, supersedes BS 6223:1982 which is withdrawn. It concerns the friction welding of metallic components for duties in which failure could lead to serious personal injury or damage to equipment. It is not directed towards any specific industry or application and it is intended to cover processes in which the heat required to effect welding is produced by friction. A classification of these processes is made within the standard, based upon the method of supplying energy and the form of relative movement. The standard is written on the basis of weld quality, specifying initial procedure approval tests, and a quality control system to check production welds. As readily available non-destructive testing techniques cannot find, with certainty, all the types of imperfection which may exist in a friction weld, such techniques are generally confined to the detection of surface defects, and reliance for quality control is placed on one, or a combination, of the following methods: a) destructive testing of sample production weldments or representative test pieces; b) proof load testing of production weldments; c) monitoring the operation of the welding machine. Regarding method (c), the particular characteristics of friction welding permit the use of monitoring techniques that give a clear indication of weld quality. Additional information considered to be useful for the comprehension of this standards requirements is included in the appendices. It has been assumed in the drafting of this British Standard that the execution of its provisions is entrusted to appropriately qualified and experienced people. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, pages 1 to 20, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 06:18:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv blank Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 06:18:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6223:1990 © BSI 06-19991 1 Scope This British Standard specifies requirements for the friction welding of components manufactured from metals. It specifies initial procedure approval tests and a quality control system to check production welds. Whilst the standard deals primarily with components of circular cross section it does not preclude the joining of other component shapes. In addition to the definitive requirements, it also requires the items, detailed in clause 3 to be documented. For compliance with this standard both the definitive requirements and the documented items have to be satisfied. Appendix A gives information on machines suitable for carrying out the work. NOTE 1It is strongly recommended that the equipment should be in accordance with Appendix A. NOTE 2The titles of the standards publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this British Standard, the following definitions apply. For other terms the definitions given in BS 499-1 apply. 2.1 friction welding a method for making welds in which one component is moved relative to and in pressure contact with the mating component to produce heat at the faying surfaces, the weld being completed by the application of a forge force during or after the cessation of relative motion NOTEThere are several forms of supplying energy and various forms of relative movement; these are given in Figure 1. 2.2 faying surface a surface of one component that is intended to be in contact with a surface of another component to form a joint 2.3 pressure contact area the initial surface contact area of the components through which the force is transmitted 2.4 interface the contact area developed between faying surfaces after completion of the welding operation 2.5 friction force the force applied normal to the faying surfaces during the time that there is relative movement between the components NOTEThis force may be varied during the friction time. 2.6 forge force the force applied normal to the faying surfaces at the time when relative movement between the components is ceasing or has ceased 2.7 burn-off length the overall length loss of the components during the application of the friction force 2.8 forge length the amount by which the overall length of the components is reduced during the application of the forge force 2.9 total length loss the loss of length that occurs as a result of friction welding, i.e. the sum of the burn-off length and the forge length 2.10 burn-off rate the rate of shortening of the components during application of the friction force 2.11 forge rate the rate of shortening of the components during the application of forge force 2.12 welding cycle the succession of operations effected by the machine for making a weldment and the return to the initial position (excluding component-handling operations) 2.13 friction pressure the pressure (force per unit area) on the faying surfaces resulting from the friction force 2.14 forge pressure the pressure (force per unit area) on the faying surfaces resulting from the forge force Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 06:18:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6223:1990 2 © BSI 06-1999 2.15 overhang the distance a component projects from the die, clamp, or chuck in the direction of the mating component 2.16 upset metal parent metal proud of the normal surfaces of the weldment as a result of friction welding 2.17 friction speed the rate of relative movement of the components 2.18 forge speed the friction speed at which the forge force is initiated 2.19 stopping time the time required by the moving component to decelerate from friction speed to zero speed 2.20 friction time the time during which relative movement between the components takes place at friction speed and under application of the friction force 2.21 forge time the time for which the forge force is applied to the components 2.22 stopping phase in the friction welding cycle the interval in which the relative motion of the components is decelerated to zero 2.23 friction phase in the friction welding cycle the interval in which the heat necessary for making a weld is generated by relative motion and the friction force between the components, i.e. from contact of components to the start of deceleration 2.24 forge phase in the friction welding cycle the interval in which the forge force takes effect on the faying surfaces 2.25 component a single item before welding 2.26 weldment two or more components joined by welding 2.27 rotating inertia the inertia of rotating parts of the machine and component that supply energy to the weld 2.28 swash the angular deviation from axial alignment 3 Information and requirements to be agreed and to be documented 3.1 Information to be supplied by the purchaser The following information to be supplied by the purchaser shall be fully documented. Both the definitive requirements specified throughout the standard and the following documented items shall be satisfied before a claim of compliance with the standard can be made and verified: a) whether heat treatment of production welds or upset removal is required (10.4); b) where relevant, the level of loads expected in service, in order to carry out proof testing (11.2.3.3). 3.2 Requirements to be agreed The following items to be agreed between the contracting parties, which are specified in the clauses referred to, shall be fully documented. Both the definitive requirements specified throughout the standard and the following documented items shall be satisfied before a claim of compliance with the standard can be made and verified: a) any variations in the preparation of the faying surfaces (clause 6); b) for procedure approval: 1) items to appear on the procedure record for the approval test sample results (10.1); 2) details of test simulation, where relevant (10.2); 3) alternative test to bend testing, where relevant (10.5); 4) additional tests to be carried out (10.5 and Appendix D); 5) alternative test procedure, where relevant, when specimens are of insufficient thickness for preparation of bend test specimens (10.6.1.2); 6) preparation of hollow specimens (10.6.2.1 and 10.6.2.2); Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 06:18:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6223:1990 © BSI 06-19993 NOTE 1Radial friction welding: a method whereby hollow components can be joined by using an intermediate ring which is rotated between them while subjected to radial forces. These forces can be generated by either compressing or expanding the ring. NOTE 2Friction surfacing: a method of deposition whereby friction between the surfacing material and the substrate is used to provide the thermo-mechanical conditions for adhesion. Figure 1 Classification of friction welding processes Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 06:18:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6223:1990 4 © BSI 06-1999 7) alternative bend test procedure (10.7.2.1) and diameter of former for combinations of materials other than those specified (10.7.2.4), where relevant (10.7.2); 8) acceptance criteria for imperfections revealed by testing (10.8.1); 9) acceptance criteria for bend testing with variation in bend angle (10.8.3); 10) acceptance criteria for hardness tests (10.8.5); c) for production quality control: 1) the system of quality control to be employed and the form and content of the records to be kept (11.1); 2) methods of test for destructive and non-destructive testing and, where relevant, proof testing (11.2.3); 3) whether requirements for test welds at the end of a shift may be reduced or deleted (11.2.3.5). d) whether post-weld inspection requires a flaw detection test and if records of inspection results are to be kept (clause 12). 4 Parent metal It shall be determined by the procedure approval tests (see clause 10) that the metal or combination of metals selected can be satisfactorily friction welded. NOTECertain features of the metallurgical structure, such as laminations or non-metallic inclusions, can be detrimental to weld quality, as can the presence of minor alloying elements naturally occurring or deliberately added to aid processing, e.g. to confer free cutting properties or for ease of casting. 5 Cross-sectional area of the joint As the geometry and cross-sectional area of a joint that can be friction welded successfully is dependent on the metals to be joined and on the c