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BS 970 EN20B vs BS 970 (Part 1) 709M40

Close Alternative — 72.6% match based on chemical composition and mechanical property overlap.

BS 970 EN20B (BS 970:1955) and BS 970 (Part 1) 709M40 (BS 970 (Part 1):1991) are both steel grades. Both fall under the Alloy Steel category. BS 970 EN20B is defined under British Standards (BS), originating from United Kingdom, while BS 970 (Part 1) 709M40 is defined under British Standards (BS), originating from United Kingdom.

As per chemical composition, BS 970 EN20B vs BS 970 (Part 1) 709M40 is a 72.6% match. Mechanical property data is not available for both grades, so this factor could not be scored. Combined, this makes them a close alternative overall at 72.6%.

Frequently Compared With BS 970 EN20B:
IS 1570 (Part 4) 07Cr4Mo6 NF A35-565 100C6 UNI 11234 100Cr6 IS 1570 (Part 4) 103Cr4 IS 1570 (Part 4) 10Cr20Mo6 IS 4367 07Cr4Mo6 IS 1570 (Part 4) 103Cr6 IS 1570 (Part 4) 105Cr5 IS 1570 (Part 7) 10Cr36Mo10H IS 4367 10Cr9Mo10 IS 1570 (Part 4) 10Mo6 IS 1570 (Part 7) 10Mo6H
Match Breakdown
CHEMISTRY MATCH
72.6%
MECHANICAL MATCH
No shared data
OVERALL
72.6%
Specifications
Property BS 970 EN20B BS 970 (Part 1) 709M40
Standard BS 970:1955 BS 970 (Part 1):1991
Category Alloy Steel Alloy Steel
C (%) 0.35-0.45 0.36-0.44
Si (%) 0.10-0.35 Not specified
Mn (%) 0.40-0.70 0.70-1.00
Cr (%) 1.00-1.50 0.90-1.20
Mo (%) 0.50-0.90 0.25-0.35
S (%) <=0.050 Not specified
P (%) <=0.050 Not specified
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 EN20B BS 970 (Part 1) 709M40
Tensile Strength ≥849 MPa (55 tons/sq in, converted) Not specified
Yield Strength ≥680 MPa (44 tons/sq in, converted) Not specified
Elongation ≥18% Not specified
Hardness 248-302 HB Not specified
Condition Hardened and tempered T, ruling section 2 1/2 in (lowest-strength condition of the standard) Not specified
Typical Applications
BS 970 EN20B
Not documented
BS 970 (Part 1) 709M40
Used for aircraft parts, heavy-duty gears, transmission shafts, connecting rods, crankshafts, and engineering fasteners.
Key Differences
Can BS 970 EN20B Be Substituted With BS 970 (Part 1) 709M40?
BS 970 EN20B and BS 970 (Part 1) 709M40 are a close alternative rather than a direct substitute. Some properties overlap well, but check the specific chemistry and mechanical rows above against your application's requirements before treating them as interchangeable.
Forms & Sizes Available on M-EX
BS 970 EN20B
No active listings currently.
BS 970 (Part 1) 709M40
Round Bar → (2 listings)
Diameter: 50–50 mm (1.97–1.97 in)
Length: 6600–6800 mm (259.84–267.72 in)
On M-EX Right Now
BS 970 EN20B
0 active listings and RFQs →
BS 970 (Part 1) 709M40
2 active listings and RFQs →
Frequently Asked Questions
What is the difference between BS 970 EN20B and BS 970 (Part 1) 709M40?
BS 970 EN20B specifies Si, S, P which are not specified for BS 970 (Part 1) 709M40.
Can BS 970 EN20B be substituted with BS 970 (Part 1) 709M40?
BS 970 EN20B and BS 970 (Part 1) 709M40 are a close alternative rather than a direct substitute. Some properties overlap well, but check the specific chemistry and mechanical rows above against your application's requirements before treating them as interchangeable.