BS 970 (Part 1):1983 080M40: 080M40 is a carbon steel grade specified in BS 970 Part 1:1983 (Table 6, category 1). Section three of the standard advises that category 1 steels be used for new designs and established designs whenever possible.
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
0.36-0.44
0.60-1.00
<=0.050
<=0.050
More data from BS 970 (Part 1):1983
From the standard
Other composition limits
Phosphorus and sulphur
Each 0.050 max (clause 1.7.2.1, carbon and carbon manganese steels)
Residual elements: see clause 1.7.3.
Source: BS 970 (Part 1):1983, Table 6
Heat treatment and maximum hardness (through hardening)
Hardening temperature
830-860 deg C
Quenching medium
Oil
Tempering temperature
550-660 deg C
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
Q
63
625-775
385
16
25
28
355
179-229
R
19
700-850
465
16
25
28
450
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
Mechanical properties, bright bar
Condition
Heat treatment condition
Size, diameter or across flats (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
Normalized + turned or ground
-
6 to 150
550 min
280
16
15
16
-
152-207 (note 4)
Normalized + turned or ground
-
over 150 to 250
510 min
245
17
-
-
-
146-197 (note 4)
Hot rolled + cold drawn or hot rolled + cold drawn + ground
-
6 to 13
660 min
530
7
-
-
495
-
Hot rolled + cold drawn or hot rolled + cold drawn + ground
-
over 13 to 16
650 min
510
8
-
-
485
-
Hot rolled + cold drawn or hot rolled + cold drawn + ground
-
over 16 to 40
620 min
480
9
-
-
435
-
Hot rolled + cold drawn or hot rolled + cold drawn + ground
-
over 40 to 63
600 min
465
10
-
-
370
-
Hot rolled + cold drawn or hot rolled + cold drawn + ground
-
over 63 to 76
570 min
430
10
-
-
350
-
Hardened and tempered + turned or ground
Q
6 to 63
625-775
385
16
25
28
355
179-229
Hardened and tempered + turned or ground
R
6 to 19
700-850
465
16
25
28
450
201-255
Hardened and tempered + cold drawn or hardened and tempered + cold drawn + ground
Q
6 to 63
625-775
435
12
25
-
380
179-229 (note 4)
Hardened and tempered + cold drawn or hardened and tempered + cold drawn + ground
R
6 to 19
700-850
490
12
25
-
460
201-255 (note 4)
Size is the diameter or across flats. For cold drawn bar of 6 mm or less, all mechanical properties are subject to agreement between purchaser and supplier at the time of enquiry and order (note 8). For normalizing and hardening and tempering treatments see Tables 3 and 7 (note 9). Rp0.2 applies when specifically ordered (note 10). 1 N/mm2 = 1 MPa. Hardness values marked note 4 are for guidance only.
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
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