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
S
P
0.25-0.35
0.05-0.35
0.60-1.00
<=0.060
<=0.060
Mechanical Properties
Tensile Strength
≥494 MPa (32 tons/sq in, converted)
Yield Strength
≥247 MPa (16 tons/sq in, converted)
Elongation
≥25%
Hardness
143-193 HB
Condition
Normalised, ruling section 2 1/2 in (lowest-strength condition of the standard)
Typical Available Sizes
Round Bar
10mm–200mm dia
Flat Bar
20×6mm–150×30mm
Sizes are indicative. Contact seller for exact availability.
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 the order states otherwise.
B
Forgings and drop-forgings in the finally heat treated condition unless the order states otherwise.
C
Bars for machining and bright bars in the finally heat treated condition unless the order states otherwise.
Source: BS 970:1955, Part 2, En 5 (page 48)
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
Normalised
2 1/2
32
16
25
20
143-193
-
Hardened and tempered P
2 1/2
35
22
22
20
152-207
-
Hardened and tempered Q
3/4
40
28*
20
20
179-229
-
Hardened and tempered R
1/2
45
32
20
40
201-255
-
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 5 (page 49)
Heat treatment
Normalise
860/890 C (material required in the normalised condition)
Harden
In oil or water from 860/890 C (material required in the hardened and tempered condition)
Temper
At a suitable temperature between 550 C and 660 C
Temperatures in degrees C as printed.
Source: BS 970:1955, Part 2, En 5 (page 48)
Notes
Note
When steel to En 5 is required in the form of plate, sheet and strip it should be ordered to B.S. 1449, Steel plate, sheet and strip.
Source: BS 970:1955, Part 2, En 5
Status in the 1955 edition
Status
Deleted by Amendment 9
Reason
Amendment 9 (Feb 1972): carbon and carbon-manganese steels moved to BS 970 Part 1:1972
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.