Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Chemical Composition (%)
C
Mn
Mo
Ni
0.20-0.26
0.35-0.75
0.20-0.30
1.50-2.00
More data from BS 970 (Part 1):1991
From the standard
Other composition limits
Category
Category 2 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
229 HB
Forgings and bars for machining, normalized, max
229 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 testHardness band
Hardness band (HRC, minimum to maximum) by distance from the quenched end (mm)
1.5
3
5
7
9
11
13
15
20
25
30
35
40
45
Distance from quenched end (mm)
1.5
3
5
7
9
11
13
15
20
25
30
35
40
45
Maximum, HRC
51
49
46
43
39
34
31
29
27
25
24
23
22
22
Minimum, HRC
44
40
33
28
26
23
22
21
20
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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