BS 970 (Part 1):1983 817A42: 817A42 is an alloy steel grade specified in BS 970 Part 1:1983 (Table 6, category 2). 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
Cr
Mo
Ni
P
S
0.40-0.45
0.45-0.70
1.00-1.40
0.20-0.35
1.30-1.70
<=0.035
<=0.040
More data from BS 970 (Part 1):1983
From the standard
Other composition limits
Phosphorus and sulphur, Z condition
0.025 max each, unless otherwise agreed (note 20)
Phosphorus and sulphur
P 0.035 max, S 0.040 max, alloy steels (clause 1.7.2.1)
Source: BS 970 (Part 1):1983, Table 6
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
T
250
850-1000
650
13
30
35
635
248-302
T
150
850-1000
680
13
40
50
665
248-302
U
100
925-1075
755
12
35
42
740
269-331
V
63
1000-1150
850
12
35
42
835
293-352
W (note 11)
29
1075-1225
940
11
30
35
925
311-375
X (note 11)
29
1150-1300
1020
10
25
28
1005
341-401
Y (note 11)
29
1225-1375
1095
10
18
21
1080
363-429
Z (note 11)
29
1550 min
1235
5
8
9
1125
444 min
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. Note 11: often ordered in the softened condition for machining and subsequent heat treatment to achieve these specified mechanical properties.
Source: BS 970 (Part 1):1983, Table 6
Comparison with earlier editions
BS 970:1970/72 designation
Not listed
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 817A42 Listings on M-EX (For Sale)