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
0.55-0.65
1.40-1.70
0.30-0.60
<=0.50
5.75-6.75
<=0.050
<=0.050
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 53 (page 159)
Mechanical properties
Condition
Ruling section or size (in)
Tensile strength (tons/sq in)
Yield stress (tons/sq in)
Elongation (%)
Izod impact (ft lb)
Brinell (HB)
Proof stress 0.2% (tons/sq in), when requested
-
-
-
-
12
235-285
-
Values as printed in BS 970:1955; tensile strength, yield stress and proof stress in tons/sq in, Izod in ft lb. Minimum unless a range is shown.
Source: BS 970:1955, Part 2, En 53 (page 159)
Other tests and requirements
Mechanical Test Samples
Test samples from bars and billets for forging over 1 1/8 in diameter forged or machined to 1 1/8 in diameter and heat treated in that size; bars of 1 1/8 in diameter and under heat treated in full size. Test pieces from forgings and bars for machining selected as in the general clauses.
Source: BS 970:1955, Part 2, En 53
Heat treatment
Harden (oil or air)
950/1000 C
Temper
suitable temperature between 720 C and 800 C
Temperatures in degrees C as printed.
Source: BS 970:1955, Part 2, En 53 (page 159)
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 EN53 Listings on M-EX (For Sale)