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BS 970 EN40A vs BS 970 EN40B

Strong Match — 94.3% match based on chemical composition and mechanical property overlap.

BS 970 EN40A (BS 970:1955) and BS 970 EN40B (BS 970:1955) are both steel grades. Both fall under the Alloy Steel category. BS 970 EN40A is defined under British Standards (BS), originating from United Kingdom, while BS 970 EN40B is defined under British Standards (BS), originating from United Kingdom.

As per chemical composition, BS 970 EN40A vs BS 970 EN40B is a 91.4% match. As per mechanical properties, the match is 100%. Combined, this makes them a strong match overall at 94.3%.

Frequently Compared With BS 970 EN40A:
IS 1570 (Part 4) 10Mo6 IS 1570 (Part 4) 10Cr20Mo6 IS 1570 (Part 4) 07Cr4Mo6 IS 1570 (Part 4) 105Cr5 IS 4367 10Cr9Mo10 IS 11169 (Part 1) 10Ni5Cr4 IS 4367 07Cr4Mo6 NF A35-565 100C6 UNI 11234 100Cr6 IS 1570 (Part 4) 103Cr4 IS 1570 (Part 4) 103Cr6 IS 1570 (Part 7) 10Cr36Mo10H
Match Breakdown
CHEMISTRY MATCH
91.4%
MECHANICAL MATCH
100%
OVERALL
94.3%
Specifications
Property BS 970 EN40A BS 970 EN40B
Standard BS 970:1955 BS 970:1955
Category Alloy Steel Alloy Steel
C (%) 0.10-0.20 0.20-0.30
Si (%) 0.10-0.35 0.10-0.35
Mn (%) 0.40-0.65 0.40-0.65
Ni (%) <=0.40 <=0.40
Cr (%) 2.90-3.50 2.90-3.50
Mo (%) 0.40-0.70 0.40-0.70
S (%) <=0.050 <=0.050
P (%) <=0.050 <=0.050
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Mechanical Properties
Property BS 970 EN40A BS 970 EN40B
Tensile Strength ≥695 MPa (45 tons/sq in, converted) ≥695 MPa (45 tons/sq in, converted)
Yield Strength ≥525 MPa (34 tons/sq in, converted) ≥525 MPa (34 tons/sq in, converted)
Elongation ≥22% ≥22%
Hardness 201-255 HB 201-255 HB
Condition Hardened and tempered R, ruling section 6 in (lowest-strength condition of the standard) Hardened and tempered R, ruling section 6 in (lowest-strength condition of the standard)
Typical Applications
BS 970 EN40A
Bars and billets for forging; forgings and drop-forgings; bars for machining; bright bars. Suitable for 45/55 (R), 50/60 (S), 55/65 (T), 60/70 (U) tons/sq in; selection of En 40A or 40B governed by tensile range required.
BS 970 EN40B
Not documented
Can BS 970 EN40A Be Substituted With BS 970 EN40B?
BS 970 EN40A and BS 970 EN40B overlap closely enough on chemistry and mechanical properties that BS 970 EN40B is often considered as a substitute for BS 970 EN40A in many applications. Always confirm the specific property range your application needs before substituting, and check with your supplier's mill certificate.
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BS 970 EN40A
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BS 970 EN40B
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Frequently Asked Questions
What is the difference between BS 970 EN40A and BS 970 EN40B?
Both grades share a similar composition profile; see the specification table above for the exact chemistry and mechanical property values.
Can BS 970 EN40A be substituted with BS 970 EN40B?
BS 970 EN40A and BS 970 EN40B overlap closely enough on chemistry and mechanical properties that BS 970 EN40B is often considered as a substitute for BS 970 EN40A in many applications. Always confirm the specific property range your application needs before substituting, and check with your supplier's mill certificate.