BS 2872:1989 download free.Specification for Copper and copper alloy forging stock and forgings.
1 Scope
BS 2872 specifies requirements for the chemical composition, tensile properties and other characteristics for wrought or cast copper and copper alloy forging stock, having a diameter or width across flats greater than 6 mm, and for forgings of these materials.
It applies to forging stock and forgings supplied in the grades of copper and copper alloys listed in Table 1 to Table 4 and the material conditions given in clause 5 for forging stock and in clause 12 for forgi ngs.
Details of information to be supplied by the purchaser are given in Appendix A.
NOTE 1 Table 9 in Appendix B indicates the alloys included in the whole series of copper and copper alloy standards. 138 2870 to BS 2875. This gives nominal compositions, product forms specified and related ISO designations.
NOTE 2 For the convenience of users of BS 2872. Table 10 in Appendix C gives conversion factors for stress values in SI and imperial units. Throughout BS 2872, values for the tensile strength and proof stress requirements are stated in newtons per square millimetre (N/mm2), this unit now being in common use in the industry.
NOTE 3 The titles of the publications referred to in BS 2872 are listed on the inside back cover.
2 DefInitions
For the purposes of BS 2872 the following definitions apply.
2.1
forging stock
extruded, rolled, drawn or cast material intended for the production of forgings, usually in the form of rod or sections
2.2
rod
a solid product of round, square, rectangular or regular polygonal cross section. uniform throughout its length, usually supplied in straight lengths, and which if rectangular in cross section has a thickness that exceeds one-tenth of the width
2.3
forging(s)
a shape produced by hammering or pressing, usually when hot, between open or closed dies, including hammering between flat surfaces. The term “forging” includes the processes of forging, drop forging, hot stamping, and hot pressing; the term “forgings” includes the products resulting from any of these processes of manufacture
2.4
wrought
a material is considered to be wrought when it has been subjected to sufficient mechanical and thermal treatment to eradicate or change substantially the original structure, usually cast
2.5
cast
cast material is material which has solidified from the liquid state in a mould, and which has not subsequently been worked to eradicate or change substantially the cast structure
3 General requirements
Forging stock shall comply with the general requirements specified in clause 4 and with the specific requirements for forging stock specified in clauses 5 to 8.
NOTE A forgeability test on the forging stock supplied may be requested by the purchaser (see item d) of A.2).
Forgings shall comply with the general requirements specified in clause 4 and with the specific requirements for forgings specified in clauses 12 to 16.
Where tests are carried out to verify that the forging stock or forgings comply with the requirements for chemical composition (see clause 4). tensile properties (see clauses 6 and 13), or resistance to dezincification (see clauses 7 and 15), the sampling and test methods shall be in accordance with clauses 9, 10 and 11 for forging stock and with clauses 17 and 18 for forgings.
The results obtained from chemical analysis and tensile tests shall be rounded to the last place of figures specified as limits, by the application of the rounding rule in accordance with BS 1957 (see Appendix D).
When mercurous nitrate testing for the residual stress in forgings is called for, the sampling shall be in accordance with 17.4.
4 Chemical composition
The chemical composition of the forging stock and forgings shall be as given for the appropriate material in Table 1 to Table 4.
5 Material condition
Wrought forging stock shall be supplied in the condition resulting from one of the following final production processes:
a) hot working:
b) cold working;
c) annealing.
NOTE At the request of the purchaser, the supplier should state whet.her the forging stock supplied is wrought or cast.
6 Tensile properties
The tensile properties of forging stock in the size range 6 mm to 80 mm shall be as given in Table 1 to Table 4 when tested in accordance with Appendix E.
NOTE 1 The tensile property requirements for forging stock outside this size range should be agreed between the purchaser and the supplier.
NOTE 2 Attention is drawn to the options available to the supplier of the forging stock concerning the preparation of the tensile test samples given in 10.1.
7 Resistance to dezincification (applicable to alloy CZ 132 only)
When a sample of forging stock in alloy CZ 132, prepared in accordance with 10.2, is subjected to the dezincification resistance test carried out in accordance with Appendix F, the maximum depth of penetration shall be as follows.
a) For wrought forging stock:
parallel to the direction of extrusion,
rolling or drawing: 200 urn
perpendicular to the direction of
extrusion, rolling or drawing: 100 lim
b) For cast forging stock:
in any direction: 100 urn
NOTE If a sample representative of the batch passes this test, it indicates that forgings produced from the batch of forging stock and correctly heat treated will pass the dezincification test requirement for forgings. The forging manufacturer should, however, still verify this by testing the forgings (see clause 15).
8 Tolerances on dimensions
NOTE 1 Each alloy in this standard has been allotted to one of two groups, designated A and B. for tolerancing purposes. A list of the alloys arid groupings, which are specific to this standard, is given in Table 5.
The diameter of round forging stock shall be within the tolerances given in Table 6 for the appropriate alloy group and size.
NOTE 2 The dimensional tolerances to be applied to round forging stock outside the range of sizes given in Table 6, and to forging stock of other shapes, should be agreed between the purchaser and the supplier.
Should both of the further samples pass the retest, the batch represented shall be deemed to comply with that particular requirement of BS 2872. Should either of the further samples fail the test, the batch represented shall be deemed not to comply with BS 2872.
11.2 Dezincification resistance test (alloy CZ 132 only)
Should any of the test pieces fail the dezincification resistance test, further samples from the same batch shall be permitted to be taken for retests. The number of samples taken for the retests shall be twice the number first selected (see note 2 to 9.1).
Should all of the further samples pass the test, the batch represented shall be deemed to comply with the dezincification resistance requirements of this standard. Should any one of the further samples fail the test, the batch represented shall he deemed not to comply with BS 2872.