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BS 970 EN39B vs BS 970 (Part 3) 817M40

Related Material — 69.9% match based on chemical composition and mechanical property overlap.

BS 970 EN39B (BS 970:1955) and BS 970 (Part 3) 817M40 (BS 970 (Part 3):1991) are both steel grades. Both fall under the Alloy Steel category. BS 970 EN39B is defined under British Standards (BS), originating from United Kingdom, while BS 970 (Part 3) 817M40 is defined under British Standards (BS), originating from United Kingdom.

As per chemical composition, BS 970 EN39B vs BS 970 (Part 3) 817M40 is a 73% match. Mechanical property data is not available for both grades, so this factor could not be scored. Combined, this makes them a related material overall at 69.9%.

Frequently Compared With BS 970 EN39B:
IS 1570 (Part 4) 10Cr20Mo6 IS 1570 (Part 4) 103Cr4 IS 1570 (Part 7) 10Cr36Mo10H IS 4367 10Cr9Mo10 IS 4367 07Cr4Mo6 IS 1570 (Part 4) 07Cr4Mo6 NF A35-565 100C6 UNI 11234 100Cr6 IS 1570 (Part 4) 103Cr6 IS 1570 (Part 4) 105Cr5 IS 1570 (Part 4) 10Mo6 IS 1570 (Part 7) 10Mo6H
Match Breakdown
CHEMISTRY MATCH
73%
MECHANICAL MATCH
No shared data
OVERALL
69.9%
Specifications
Property BS 970 EN39B BS 970 (Part 3) 817M40
Standard BS 970:1955 BS 970 (Part 3):1991
Category Alloy Steel Alloy Steel
C (%) 0.12-0.18 0.36-0.44
Si (%) 0.10-0.35 0.10-0.40
Mn (%) <=0.50 0.45-0.70
Ni (%) 3.80-4.50 1.30-1.70
Cr (%) 1.00-1.40 1.00-1.40
Mo (%) 0.15-0.35 0.20-0.35
S (%) <=0.050 <=0.040
P (%) <=0.050 <=0.035
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 EN39B BS 970 (Part 3) 817M40
Tensile Strength ≥1313 MPa (85 tons/sq in, converted) Not specified
Elongation ≥12% Not specified
Condition Core, after heat treatment (lowest-strength condition of the standard) Not specified
Typical Applications
BS 970 EN39B
Not documented
BS 970 (Part 3) 817M40
High tensile shafts, gears, crankshafts
Can BS 970 EN39B Be Substituted With BS 970 (Part 3) 817M40?
BS 970 EN39B and BS 970 (Part 3) 817M40 share some compositional similarity but differ enough that substitution should not be assumed. Review the differences above carefully, and consult the applicable standard or a metallurgist before using one in place of the other.
Forms & Sizes Available on M-EX
BS 970 EN39B
No active listings currently.
BS 970 (Part 3) 817M40
Round Bar → (2 listings)
Diameter: 50–50 mm (1.97–1.97 in)
Length: 6200–6500 mm (244.09–255.91 in)
On M-EX Right Now
BS 970 EN39B
0 active listings and RFQs →
BS 970 (Part 3) 817M40
2 active listings and RFQs →
Frequently Asked Questions
What is the difference between BS 970 EN39B and BS 970 (Part 3) 817M40?
Both grades share a similar composition profile; see the specification table above for the exact chemistry and mechanical property values.
Can BS 970 EN39B be substituted with BS 970 (Part 3) 817M40?
BS 970 EN39B and BS 970 (Part 3) 817M40 share some compositional similarity but differ enough that substitution should not be assumed. Review the differences above carefully, and consult the applicable standard or a metallurgist before using one in place of the other.