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
Ni
P
S
0.18-0.23
0.70-0.90
0.40-0.60
0.15-0.25
0.40-0.70
<=0.035
<=0.040
More data from BS 970 (Part 1):1983
From the standard
Other composition limits
Phosphorus and sulphur
P 0.035 max, S 0.040 max, alloy steels (clause 1.7.2.1)
Residual elements: see clause 1.7.3.
Source: BS 970 (Part 1):1983, clause 1.7.2.1
Mechanical properties, test bar
Test bar diameter (mm)
Rm min (N/mm2)
A min (%)
Izod min (ft lbf)
KCV min (J)
19
850
11
15
16
Values as printed in Table 11 for the test bar diameter shown. 1 N/mm2 = 1 MPa.
Source: BS 970 (Part 1):1983, Table 11
Comparison with earlier editions
BS 970:1970/72 designation
805A20
BS 970:1955 En No.
None
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
Active BS 970 (Part 1):1983 805A20 Listings on M-EX (For Sale)