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
Ni
Cr
S
P
0.74-0.84
1.75-2.25
0.20-0.60
1.15-1.65
19.0-20.5
<=0.030
<=0.030
More data from BS 970:1955
From the standard
Condition of material on delivery
A
Bars and billets for forging as rolled or forged unless order states otherwise.
B
Forgings and drop-forgings finally heat treated unless order states otherwise.
C
Bars for machining finally heat treated unless order states otherwise.
D
Bright bars in the condition stated on the order.
Source: BS 970:1955, Part 2, En 59 (page 173)
Other tests and requirements
Steel shall be capable of local hardening by oil quenching to a Rockwell C hardness of not less than 47 or equivalent Vickers hardness number (480, per BS 860).
Local hardening by oil quenching Rockwell C hardness
47
Local hardening by oil quenching Vickers hardness number (equivalent)
480
Source: BS 970:1955, Part 2, En 59
Heat treatment
Harden (oil or air)
1050/1080 C
Temper
suitable temperature between 700 C and 750 C
Temperatures in degrees C as printed.
Source: BS 970:1955, Part 2, En 59 (page 173)
Status in the 1955 edition
Status
Deleted by Amendment 6
Reason
Amendment 6 (Feb 1970): stainless, heat resisting and valve steels moved to BS 970 Part 4:1970
BS 970:1955 was amended up to Amendment 10 (June 1972); steels were moved to the revised Parts 1 to 5 and deleted from this edition.
Source: BS 970:1955, Amendment slips 6 to 10
Active BS 970:1955 EN59 Listings on M-EX (For Sale)