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
0.15-0.23
1.00-1.40
<=0.050
<=0.050
More data from BS 970 (Part 1):1983
From the standard
Other composition limits
Silicon
Not specified for this grade; a maximum silicon content can be agreed between purchaser and supplier (Table 2, note 5)
Phosphorus and sulphur
Each 0.050 max (clause 1.7.2.1, carbon and carbon manganese steels)
Values as printed in Table 2 for the limiting ruling section shown.
Source: BS 970 (Part 1):1983, Table 2 and Table 3
Heat treatment and maximum hardness (through hardening)
Hardening temperature
860-900 deg C
Quenching medium
Oil or water
Tempering temperature
550-660 deg C
Hardenability test
No hardenability data specified
Softened condition
Not usually supplied in the softened condition
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.
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
P
100
550-700
355
18
35
42
325
152-207
Q
29
625-775
450
16
35
42
415
179-229
R
19
700-850
510
16
25
28
495
201-255
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.
Source: BS 970 (Part 1):1983, Table 6
Comparison with earlier editions
BS 970:1970/72 designation
120M19
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
Normalizing temperature
Normalizing temperature (C)
860-900
Table 3, category 1.
Source: BS 970 (Part 1):1983, Table 3
Active BS 970 (Part 1):1983 120M19 Listings on M-EX (For Sale)