BS 970 (Part 1):1983 835M30: 835M30 is an alloy steel grade specified in BS 970 Part 1:1983 (Table 6, category 1). 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
Ni
0.26-0.34
0.45-0.70
<=0.025
<=0.025
1.10-1.40
0.20-0.35
3.90-4.30
More data from BS 970 (Part 1):1983
From the standard
Heat treatment and maximum hardness (through hardening)
Hardening temperature
810-840 deg C
Quenching medium
Oil (air hardening may be used where the ruling section does not exceed 63 mm, note 26)
Tempering temperature
200-280 deg C
Hardenability test
No hardenability data specified
Maximum hardness HB, softened condition
255
Maximum hardness HB, temper softened condition
277
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 26: where the ruling section does not exceed 63 mm air hardening may be employed.
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
Z (note 11)
150
1550 min
1235
7
15
16
1125
444 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. Note 11: often ordered in the softened condition for machining and subsequent heat treatment to achieve these specified mechanical properties.
Source: BS 970 (Part 1):1983, Table 6
Comparison with earlier editions
BS 970:1970/72 designation
835M30
BS 970:1955 En No.
30B
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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