1、BRITISH STANDARD AEROSPACE SERIES BSHC 401:1974 Specification for 18% nickel maraging steel precision castings (16001850 MPa) UDC 629.7:669.1524145:669.14.018.298.3BSHC401:1974 This British Standard, having been approved by the AerospaceIndustry Standards Committee, was published underthe authority
2、of the Executive Board on 29November1974 BSI 01-2000 The following BSI references relate to the work on this standard: Committee reference ACE/60 Draft for comment 73/33283 DC ISBN 0 580 08800 6 A British Standard does not purport to include all the necessary provisions of a contract. Users of Briti
3、sh 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 and ii, pages 1 and 2 and a back cover. This standard has b
4、een updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date CommentsBSHC401:1974 BSI 01-2000 i Contents Page 1 Special foundry approval 1 2 Inspection and testing
5、 procedure 1 3 Manufacture 1 4 Chemical composition 1 5 Condition 1 6 Heat treatment 1 7 Mechanical properties 2 8 Rectification of defects 2ii blankBSHC401:1974 BSI 01-2000 1 1 Special foundry approval Manufacture of castings to this specification may be restricted to foundries specially approved i
6、n accordance with the requirements of BSHC100, Section 1. 2 Inspection and testing procedure This British Standard shall be used in conjunction with the relevant sections of BS HC 100 as follows: 3 Manufacture Re-melting stock and castings shall be produced by melting and casting under vacuum. 4 Che
7、mical composition The re-melting stock and the castings shall contain: 5 Condition Unless otherwise agreed, castings shall be supplied in the solution treated condition. 6 Heat treatment The procedure for heat treatment shall be in accordance with 6.1 or 6.2. 6.1 Procedure 1 6.1.1 Homogenization tre
8、atment a) Section thickness of not more than 25 mm. Heat in vacuum or an inert atmosphere at a temperature of 980 10 C for 4 h and cool in an inert atmosphere to room temperature. b) Section thickness greater than 25mm but not more than 75 mm. Heat in vacuum or an inert atmosphere at a temperature o
9、f 1150 10 C for 4 h and cool in an inert atmosphere to room temperature. 6.1.2 Conditioning treatment. Heat at a temperature of 590 5 C for 4 h and cool in air to room temperature. 6.1.3 Solution treatment. Heat in vacuum or an inert atmosphere at a temperature of 815 10 C for 2h and cool to room te
10、mperature in an inert atmosphere. 6.1.4 Maraging treatment. Heat at a temperature of 480 5 C for 3 h and cool in air. Re-melting stock Sections 1 and 2 Precision castings Sections 1 and 3 Element % min. max. Carbon 0.03 Silicon 0.10 Manganese 0.10 Phosphorus 0.010 Sulphur 0.010 Aluminium 0.02 0.15 C
11、obalt 9.5 11.0 Chromium 0.25 Molybdenum 4.4 4.9 Nickel 16.0 17.5 Titanium 0.15 0.60BSHC401:1974 2 BSI 01-2000 6.2 Procedure 2 6.2.1 Homogenization treatment. Heat in vacuum at a temperature of 1 150 10 C for not less than4h and cool in an inert atmosphere to room temperature. 6.2.2 Solution treatmen
12、t. Heat in vacuum at a temperature of 1 050 10 C for not less than 4 h and cool in an inert atmosphere to room temperature. 6.2.3 Maraging treatment. Heat at a temperature of 480 5 C for 3 h and cool in air. 7 Mechanical properties 7.1 Tensile and impact. The room temperature tensile and impact prop
13、erties obtained from test pieces representing castings, selected, prepared and tested in accordance with the relevant requirements of BSHC 100, shall be: NOTEInformation on SI units is given in BS 3763 “The International System of units (SI)”, and BS 350 “Conversion factors and tables”. 7.2 Hardness
14、 7.2.1 The hardness of solution treated castings and of their representative test samples shall be not greater than 341 HB, 365 HV or 36 HRC. 7.2.2 The hardness of maraged castings and of their representative test samples shall be: 8 Rectification of defects 8.1 When permitted in accordance with BSH
15、C 100, Section 1, correction of distortion and/or repair by welding shall be carried out after solution treatment and castings shall subsequently be maraged. 8.2 Welding repair shall be carried out using an inert gas shield or in vacuum. 0.2% proof stress Tensile strength Elongation Reduction of are
16、a Izod impact min. min. max. min. min. min. Mpa (= N/mm 2 ) Mpa (= N/mm 2 ) Mpa (= N/mm 2 ) % % ft lbf 1 500 1 600 1 850 6 25 10 min. max. HB HV HRC 461 495 49 555 650 58blankBSHC 401:1974 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body re
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