1、BRITISH STANDARD BS5998:1983 Specification for Quality levels for steel valve castings UDC 621.646.2:669.14-14BS5998:1983 This British Standard, having been prepared under the directionof the Mechanical Engineering Standards Committee, was published underthe authority of the BoardofBSI and comes int
2、oeffecton 31 August1983 BSI 06-1999 The following BSI references relate to the work on this standard: Committee reference MEE/191 Draft for comment79/73440DC ISBN 0 580 13380 X Cooperating organizations The Mechanical Engineering Standards Committee, under whose direction this British Standard was p
3、repared, consists of representatives from the following: Associated Offices Technical Committee* Department of Trade (Marine Division) Association of Consulting Engineers Department of Transport Association of Hydraulic Equipment Electricity Supply Industry in England and Manufacturers* Wales* Assoc
4、iation of Mining Electrical and Energy Industries Council* Mechanical Engineers Engineering Equipment Users Association* British Compressed Air Society Federation of Manufacturers of Construction British Constructional Steelwork Association Equipment and Cranes British Electrical and Allied Manufact
5、urers Health and Safety Executive* Association (BEAMA) Institution of Gas Engineers* British Gas Corporation* Institution of Mechanical Engineers* British Gear Manufacturers Association Institution of Plant Engineers British Internal Combustion Engine Institution of Production Engineers Manufacturer
6、s Association Lloyds Register of Shipping British Pump Manufacturers Association London Transport Executive British Steel Corporation Machine Tool Industry Research Association British Steel Industry* Ministry of Defence* British Valve Manufacturers Association Ltd. National Coal Board* Chartered In
7、stitution of Building Services Oil Companies Materials Association* Crown Agents for Oversea Governments and Process Plant Association Administrations Society of Motor Manufacturers and Traders Department of Industry (Mechanical Limited Engineering) Telecommunication Engineering and Department of In
8、dustry (National Manufacturing Association (TEMA) Engineering Laboratory) Water-tube Boilermakers Association Department of the Environment (PSA) The organizations marked with an asterisk in the above list, together with the following, were directly represented on the Technical Committee entrusted w
9、ith the preparation of this British Standard: Amalgamated Union of Engineering Workers Council of Ironfoundry Associations Association of Bronze and Brass Founders General Council of British Shipping British Chemical Engineering Contractors Greater London Council Association Institute of British Fou
10、ndrymen British Compressed Gases Association Institution of Chemical Engineers British Industrial Measuring and Control Institution of Civil Engineers Apparatus Manufacturers Association Institution of Water Engineers and Scientists (BEAMA) National Brassfoundry Association British Ship Research Ass
11、ociation National Water Council British Shipbuilders Society of British Gas Industries Copper Development Association Steel Castings Research and Trade Association Copper Tube Fittings Manufacturers Water Companies Association Association Amendments issued since publication Amd. No. Date of issue Co
12、mmentsBS 5998:1983 BSI 06-1999 i Contents Page Cooperating organizations Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Methods for non-destructive testing 1 4 Inspection quality levels 1 5 Non-destructive examination 1 6 Rectification or repair by welding 2 7 Identification 2 8 Test cer
13、tificate 2 Appendix A Records and test certificate 4 Appendix B Information to be supplied by purchaser 4 Figure 1 Butt-weld end 1 Table 1 Quality levels and inspection requirements 2 Table 2 Acceptance standards for castings up to51mm(2in) thickness 2 Table 3 Acceptance standards for castings betwe
14、en51mm and114mm(2inand4in) thickness 3 Table 4 Acceptance standards for castings between114mm and305mm(4 inand12in) thickness 3 Publications referred to Inside back coverBS5998:1983 ii BSI 06-1999 Foreword This British Standard has been prepared under the direction of the Mechanical Engineering Stan
15、dards Committee. Its purpose is to enable valves of appropriate quality to be selected for the duties intended and the manufacturer to indicate his quality levels. The implementation of this standard is dependent upon the use of specimen radiographs prepared by the American Society for Testing and M
16、aterials and copies of these radiographs may be examined at the offices of the Steel Castings Research and Trade Association (SCRATA) 1) , by prior appointment only, at no charge. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards ar
17、e 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, pagesi andii, pages1 to4, an inside back cover and a back cover. This standard has
18、 been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. 1) Steel Castings Research and Trade Association,5East Bank Road, Sheffield S23PT.BS5998:1983 BSI 06-1999 1 1 Scope This British Standard specifies qu
19、ality levels for steel castings for the pressure containing components of valves and requirements for inspection and identification of steel castings. The aim of this standard is to ensure integrity of the pressure containing components, e.g.body and bonnet, by specifying quality requirements, appro
20、priate records and casting identification. The requirements of this standard are additional to any casting requirements, e.g.material properties, that are specified in any other standard relating to valves. NOTEThe titles of the publications referred to in this standard are listed on the inside back
21、 cover. 2 Definitions For the purposes of this British Standard the following definition applies. butt-weld end that region of the casting that extends from the machined extremity of the butt-weld preparation a distance of1.5t or50mm, whichever is the lesser (see Figure 1) 3 Methods for non-destruct
22、ive testing The methods for non-destructive testing shall be in accordance with BS4080. 4 Inspection quality levels Manufacturers shall supply details of critical areasof pressure containing castings to be non-destructively examined in respect of the following senses (see also Appendix B): a) castin
23、g solidification; b) stress concentration; c) ability to contain pressure. Quality levels shall be as given in Table 1. 5 Non-destructive examination 5.1 Acceptance standards for non-destructive examination 5.1.1 General. The categories and severity levels shall comply with5.1.2 to5.1.5, as appropri
24、ate (seeTable 1). 5.1.2 Acceptance standards for visual inspection. Inall cases, the acceptance standard for visualinspection shall comply with MSS-SP55-1971(reaffirmed1980) 2) . 5.1.3 Acceptance standards for magnetic particle inspection related to linear discontinuities only. All linear discontinu
25、ities shall not be in excess of Type1, Degree2as illustrated in ASTM E125-1965. 5.1.4 Acceptance standards for liquid penetrant inspection related to linear discontinuities only. All linear discontinuities shall not be in excess of Type1, Degree2as illustrated in ASTM E125-1963. 2) “Quality Standard
26、 for Steel Castings for Valves, Flanges and Fittings and Other Piping Components (Visual Method)”, published by the Manufacturers Standardization Society (of America) and available from BSI Technical Help to Exporters, Linford Wood, Milton Keynes MK146LE, Tel. Milton Keynes320033. Figure 1 Butt-weld
27、 endBS5988:1983 2 BSI 06-1999 5.1.5 Acceptance standards for radiographic inspection.Acceptance categories and severity levels of radiographic indications for quality levels I,II andIII shall be as given in Table 2, Table 3 and Table 4. In all cases there shall be no hot tears, cracks, unfused chapl
28、ets, chills or inserts. 6 Rectification or repair by welding If castings are rectified or repaired, such rectification or repair shall be in accordance with the requirements of BS4570-1, and welded areas shall be re-inspected in accordance with the casting quality level. 7 Identification Castings ma
29、nufactured by the shell moulding technique shall be identified by a cast-on code relating to the month of manufacture. Castings manufactured by the green/dry sand technique shall be identified by a cast-on code relating to the day of manufacture. These identification codes shall be related to all co
30、ntrol information at the founders. 8 Test certificate All valve castings that comply with this BritishStandard shall be supplied with a test certificate of compliance to this standard quoting the number of this British Standard, i.e.BS5998 (see also Appendix A). Table 1 Quality levels and inspection
31、 requirements Table 2 Acceptance standards for castings up to51mm(2in) thickness (ASTM E446:1978) aQuality level Inspection requirements Magnetic steels Non-magnetic steels Visual Magnetic particle (MPI) Radiographic Visual Liquid penetrant Radiographic I 100% of pressure containing parts 100% of pr
32、essure containing parts 100% of pressure containing parts 100% of pressure containing parts II III All pressure containing parts Nominated areas Nominated areas All pressure containing parts Nominated areas Nominated areas IV V NOTEThe percentage of castings to be inspected is outside the scope of t
33、his standard and should be agreed between the valve manufacturer and the purchaser at the time of enquiry and/or order. Discontinuity type Category Severity level Other than butt-weld ends Butt-weld ends Casting quality level Casting quality level III I and II I, II and III Gas porosity Sand and sla
34、g inclusions Shrinkage: A B 3 3 2 2 All level2 Type CA Type CB Type CC Type CD C C C C 4 4 4 4 3 3 2 2 a For availability of radiographs, attention is drawn to the foreword. BS5998:1983 BSI 06-1999 3 Table 3 Acceptance standards for castings between51mm and114mm (2in and4 in) thickness (ASTM E186:19
35、75) aTable 4 Acceptance standards for castings between 114mm and305mm (4in to12in) thickness (ASTME280:1975) a Discontinuity type Category Severity level Other than butt-weld ends Butt-weld ends Casting quality level Casting quality level III I and II I, II and III Gas porosity Sand and slag inclusi
36、ons Shrinkage: A B 3 3 2 2 All level2 Type1 Type2 Type3 C C C 4 4 4 3 3 2 a For availability of radiographs, attention is drawn to the foreword. Discontinuity type Category Severity level Other than butt-weld ends Butt-weld ends Casting quality level Casting quality level III I and II I, II and III
37、Gas porosity Sand and slag inclusions Shrinkage: A B 3 3 2 2 All level2 Type1 Type2 Type3 C C C 4 4 4 3 3 2 a For availability of radiographs, attention is drawn to the foreword. BS5988:1983 4 BSI 06-1999 Appendix A Records and test certificate Since the test certificate of the quality of the produc
38、t is as important as the product itself, it is recommended that a purchaser should consider including the following in his contract with the supplier. a) The test certificate of the chemical analysis and mechanical tests, giving details of the variation over the appropriate period given in clause7,
39、of the chemical and physical properties and, when applicable, certification that the ratios of the chemical elements of individual melts comply with the purchasers specification. b) An instruction that the founder should retain castings records for a period of5 years and such records should include
40、chemical and mechanical tests for all quality levels together with radiography records, including radiographs, for quality levelsI,II andIII. Appendix B Information to be supplied by purchaser The purchaser should supply the following information. a) Quality level and inspection required. b) Details
41、 required of areas non-destructively tested (see clause4).BS5988:1983 BSI 06-1999 Publications referred to BS4080, Methods for non-destructive testing of steel castings. BS4570, Fusion welding of steel castings. BS4570-1, Production, rectification and repair. ASTME175, Standard reference photographs
42、 for magnetic particle indication on ferrous castings. ASTME186, Standard reference radiographs for heavy-walled (2to4 in. 51to114mm) steel castings. ASTME280, Standard reference radiographs for heavy-walled 4to12in. (114 to305mm) steel castings. ASTME446, Standard reference radiographs for steel ca
43、stings up to2 in. (51mm) in thickness. MSS SP55, Quality Standard for Steel Castings for Valves, Flanges and Fittings and Other Piping Components (Visual Method). BS5998:1983 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for
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