BS 970 (Part 1):1983 897M39: 897M39 is an alloy steel grade specified in BS 970 Part 1:1983 (Table 6, category 2). Section three of the standard advises that category 1 steels be used for new designs and established designs whenever possible.
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Chemical Composition (%)
C
Mn
P
S
Cr
Mo
V
0.35-0.43
0.45-0.70
<=0.025
<=0.025
3.00-3.50
0.80-1.10
0.15-0.25
More data from BS 970 (Part 1):1983
From the standard
Other composition limits
Suitable for nitriding
When so ordered by the purchaser, in which case 4 x P plus Sn must not exceed 0.10% (note 23)
Source: BS 970 (Part 1):1983, Table 6
Heat treatment and maximum hardness (through hardening)
Hardening temperature
920-970 deg C
Quenching medium
Oil
Tempering temperature
550-700 deg C
Hardenability test
No hardenability data specified
Heat treatment to be given to test bars and to material required in the finally heat treated condition. Note 24: O = oil, W = water. Where oil hardening is specified, either a well-agitated conventional oil or a proven synthetic quenchant may be used. Synthetic quenchants shall not be used for the heat treatment of test bars for material not supplied in the finally heat treated condition. Note 25: suitable for nitriding. Where parts are to be nitrided, the steel shall be hardened and tempered in accordance with Table 7 but the tempering temperature shall be at least 30 deg C above the temperature to be employed for nitriding. Table 7 prints no softened-condition hardness for this steel.
Source: BS 970 (Part 1):1983, Table 7
Mechanical properties by heat treatment condition
Condition
Limiting ruling section (mm)
Rm (N/mm2)
Re min (N/mm2)
A min (%)
Izod min (ft lbf)
KCV min (J)
Rp0.2 min (N/mm2), when specifically ordered
HB
Not lettered
63
1310 min
1160
8
15
16
1110
375 min
Values as printed in Table 6 for the limiting ruling section shown. Rp0.2 applies when specifically ordered (note 10). 1 N/mm2 = 1 MPa.
Source: BS 970 (Part 1):1983, Table 6
Comparison with earlier editions
BS 970:1970/72 designation
897M39
BS 970:1955 En No.
40C
Appendix D note 47: where a comparison is made the steels are not necessarily equivalent. 'Not listed' means the earlier edition has no entry under this designation.
Source: BS 970 (Part 1):1983, Appendix D
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