Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Chemical Composition (%)
C
Mn
Cr
0.12-0.18
0.30-0.60
0.30-0.60
More data from BS 970 (Part 1):1991
From the standard
Other composition limits
Category
Category 1 steel
Category 1 steels are preferred for new designs and established designs (clauses 1.4 and 2.1). Category 2 steels are printed in italic type.
Source: BS 970 (Part 1):1991, Table 7
Maximum hardness by condition of delivery
Bars and billets for forging, max
207 HB
Forgings and bars for machining, normalized, max
207 HB
Maximum Brinell hardness when specified on the order, in the condition of delivery (Table 9).
Source: BS 970 (Part 1):1991, Table 9
Hardenability, end quench test (HV 20 or 30)Hardness band
Hardness band (HV 20 or 30, minimum to maximum) by distance from the quenched end (mm)
1.25
2.0
2.75
3.5
4.25
5.0
5.75
6.5
7.25
9.0
10.5
12.0
15.0
20.0
25.0
Distance from quenched end (mm)
1.25
2.0
2.75
3.5
4.25
5.0
5.75
6.5
7.25
9.0
10.5
12.0
15.0
20.0
25.0
Maximum, HV
510
490
445
385
340
315
295
280
260
235
220
215
210
205
200
Minimum, HV
380
340
280
240
200
180
H grade requirement for case hardening steels; see also the curves in Appendix A, which are for guidance only.
Source: BS 970 (Part 1):1991, Table 7
Heat treatment
Preheat treatment temperature, hardenability test
930-950 deg C
Austenitizing temperature, hardenability test
925 deg C
Table 9: heat treatment of case hardening steels. Values as printed; a dash in the table means not specified.
Source: BS 970 (Part 1):1991, Table 9
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