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
Mo
0.17-0.23
0.60-0.90
0.85-1.15
0.15-0.25
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
Forgings and bars for machining, normalized and tempered, max
217 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
47
47
46
44
41
39
36
35
33
31
30
29
28
28
Minimum, HRC
39
38
35
32
29
26
22
22
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
Active BS 970 (Part 1):1991 708H20 Listings on M-EX (For Sale)