BS 970:1955 EN56AM: EN56AM: Chromium rust-resisting steel (free machining): En 56AM, 56BM, 56CM, 56DM. Bars and billets for forging; forgings and drop-forgings; bars for machining; bright bars. Specified in BS 970:1955, Part 2.
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
Mo
S
Se
Zr
Pb
P
<=0.12
<=1.00
<=1.50
<=1.00
12.0-14.0
<=0.60
<=0.75
<=0.60
<=0.60
<=0.35
<=0.045
Mechanical Properties
Tensile Strength
≥541 MPa (35 tons/sq in, converted)
Elongation
≥20%
Hardness
152-207 HB
Condition
Hardened and tempered P, ruling section 6 in (lowest-strength condition of the standard)
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 finally heat treated, before or after cold work at manufacturer option, unless order states otherwise.
Source: BS 970:1955, Part 2, En 56AM (page 167)
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
Hardened and tempered P
6
35
-
20
25
152-207
-
Hardened and tempered R
6
45
-
15
20
201-255
-
Hardened and tempered S
4
50
-
12
-
223-277
-
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 56AM (page 167)
Heat treatment
Harden (oil or air)
950/1020 C
Temper
suitable temperature not exceeding 750 C
Temperatures in degrees C as printed.
Source: BS 970:1955, Part 2, En 56AM (page 167)
Notes
Note
Molybdenum, selenium, zirconium and lead: total 1.00 per cent max.
Note
Plate, sheet and strip to BS 1449; wire to BS 1554.
Source: BS 970:1955, Part 2, En 56AM
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 EN56AM Listings on M-EX (For Sale)