Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Chemical Composition (%)
C
Si
Mn
P
S
Cr
Mo
Ni
0.09-0.15
<=1.0
<=1.5
<=0.060
0.15-0.35
11.5-13.5
<=0.60
<=1.00
More data from BS 970 (Part 1):1991
From the standard
Other composition limits
Category
Category 1 steel (note 7)
Maximum unless a range is stated.
Source: BS 970 (Part 1):1991, Table 10
Mechanical properties by heat treatment condition
Condition
Limiting ruling section (mm)
Heat treatment (deg C)
Tensile strength Rm (MPa)
Yield Re, min (MPa)
Elongation, min (%)
Impact Izod, min (ft lb)
Rp0.2, min (MPa)
Hardness HB
P
150
950-1020 (33); 650-750 (34)
550-700
370
15
25
340
152-207
R
63
950-1020 (33); 600-700 (34)
700-850
525 (scan may read 526)
11
20
495
201-255
Heat treatment: (31) air cooled or furnace cooled, (32) cooled freely in air, (33) oil or air hardened, (34) tempered, (35) when 0.2 % proof stress is specified a double tempering treatment is recommended: 640 to 680 deg C followed by 590 to 610 deg C. Rp0.2 applies when specifically ordered (note 10). Condition letters P, R, S, T as printed.
Source: BS 970 (Part 1):1991, Table 10
Hardness in the softened condition
Softened condition, max
207 HB
Table 10, softened condition.
Source: BS 970 (Part 1):1991, Table 10
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