BS 2970:1989 download free.Specification for Magnesium and magnesium alloy Ingots and castings.
1 Scope
BS 2970 specifies requirements for chemical composition, mechanical properties and other characteristics for the following two types of product for general engineering purposes:
a) magnesium and magnesium alloy ingots intended to be remelted for the production of castings: and
b) magnesium and magnesium alloy castings.
BS 2970 applies to castings made by any metal casting process. For mechanical properties, however, requirements are specified only for castings made by the sand casting and chill casting processes.
Details of information to be supplied by the purchaser in any enquiry or order are given in Appendix A. Appendix B describes chemical analysis procedures for ingots and castings and Appendix C describes tensile testing of castings. Appendix D gives guidance on additional inspection and test procedures for castings, including a classification system for castings that enables these test procedures to be agreed readily at the design stage, for quotation purposes and for order. Typical hardness values are given in Appendix E; Appendix F specifies colour coding for ingots; Appendix G gives guidance on the selection of alloys:
and Appendix H gives design considerations for corrosion resistance.
NOTE The titles of the publications referred to in this standard are listei on the inside back cover.
2 Definitions
For the purposes of BS 2970 the following definitions apply.
2.1
ingot
a cast, unwrought product, in a form suitable for remelting
2.2
approved ingots
magnesium and magnesium alloy ingots which have been proved to comply with the appropriate material specification
2.3
approved scrap
that scrap which arises from a founder’s own production from approved ingots, which is segregated and identifiable. It may include heavy fettling scrap but be free from all drosses and small particles such as sawings, grindings and chippings
2.4
ingot batch
a series of ingots cast from a single uniform melt
2.5
casting
a product at or near finished shape, formed by solidification of a metal or alloy in a mould
2.6
sand casting
a casting formed in a sand mould
2.7
chill casting
a casting formed in a metal mould
2.8
gravity die casting
a chill casting in which the molten metal is introduced by gravity
2.9
low-pressure casting
a chill or sand casting in which the molten metal is introduced by a low-pressure feed
2.10
pressure die casting
a chill casting in which the molten metal is introduced under a pressure in excess of 2 x iO Pa
2.11
investment casting
a casting formed from an expendable pattern which has been invested in a suitable mould material
2.12
cast (non-continuous melting)
the product of either one furnace melt, or a number of furnace melts where such are aggregated and mixed prior to sampling or pouring
2.13
cast (continuous melting)
in continuous melting for the production of castings, when the contents of a melting/holding furnace are supplemented from time to time by the addition of metal to maintain an adequate bulk of liquid metal, a cast is 500 kg or fraction thereof of metal poured
2.14
manufacturer
manufacturer of ingots
2.15
supplier
foundry or founder which supplies castings
3 Ingots
3.1 Chemical composition
The chemical composition of magnesium ingots shall be as given in Table 1 for the appropriate alloy, when determined in accordance with Appendix B.
3.2 Certificate of analysis
A certificate of analysis shall be supplied with each cast of ingots. The certificate shall provide the analysis to the specified elements of sample(s) representative of the cast.
3.3 Marking
Ingots shall be marked clearly and durably with:
a) the number and date of this British Standard, i.e. BS 297O:1989’ and
b) either the manufacturers mark, the material designation and the cast number; or
c) in bundles, with each bundle marked with the manufacturer’s mark, the material designation and the cast number. Ingots shall be colour-marked to identify the alloy in which they have been cast.
NOTE Appendix F lists suitable colour codes.
4 Castings
4.1 Chemical composition
The chemical composition of magnesium alloy castings shall be as given in Table 2 for the appropriate alloy, when determined in accordance with Appendix B.
4.2 Condition
The castings shall be supplied in one of the following conditions (see Table 3):
as cast (M)
precipitation treated (TE)
solution treated and quenched (TB)
solution treated, quenched and precipitation
treated (TF).
NOTE This should be advised by the purchaser when ordering. If stress-relieving treatment (TS) is required, details of the stress-relieving procedure to be applied should he stated on the order. [See item b) 3) of Appendix Al
4.3 Mechanical properties
The tensile properties shall be as given in Table 3, when determined in accordance with Appendix C.
NOTE The tensile property requirements are specified for separately cast test samples. They do not necessarily represent the properties obtainable from all parts, or in all directions, of a casting. which will depend on a number of factors including wall thickness and cooling characteristics.
4.4 Certificate of compliance
When requested [see item b) 8) of Appendix A], the supplier shall certify that the castings comply with this standard.
4.5 Marking
Castings shall be marked clearly and durably with:
a) the number and date of this British Standard,
i.e. BS 297O:1989 and
b) the manufacturer’s mark, the material
designation and the cast number.