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BS 970 (Part 3) 817M40 vs BS 970 (Part 1) 817A42

Strong Match — 89.5% match based on chemical composition and mechanical property overlap.

BS 970 (Part 3) 817M40 (BS 970 (Part 3):1991) and BS 970 (Part 1) 817A42 (BS 970 (Part 1):1983) are both steel grades. Both fall under the Alloy Steel category. BS 970 (Part 3) 817M40 is typically used for high tensile shafts, gears, crankshafts, while BS 970 (Part 1) 817A42 is commonly used for through hardening steel for mechanical and allied engineering purposes; supplied in the hardened and tempered conditions of table 6.. BS 970 (Part 3) 817M40 is defined under British Standards (BS), originating from United Kingdom, while BS 970 (Part 1) 817A42 is defined under British Standards (BS), originating from United Kingdom.

As per chemical composition, BS 970 (Part 3) 817M40 vs BS 970 (Part 1) 817A42 is a 89.5% match. Mechanical property data is not available for both grades, so this factor could not be scored. Combined, this makes them a strong match overall at 89.5%.

Frequently Compared With BS 970 (Part 3) 817M40:
GOST 4543 12HN3A UNI 11234 100Cr6 GB/T 3077 12Cr2Ni4A NF A35-565 100C6 IS 1570 (Part 4) 103Cr6 IS 1570 (Part 4) 07Cr4Mo6 IS 1570 (Part 4) 10Cr20Mo6 IS 4367 07Cr4Mo6 IS 1570 (Part 4) 103Cr4 IS 1570 (Part 4) 105Cr5 IS 1570 (Part 7) 10Cr36Mo10H IS 4367 10Cr9Mo10
Match Breakdown
CHEMISTRY MATCH
89.5%
MECHANICAL MATCH
No shared data
OVERALL
89.5%
Specifications
Property BS 970 (Part 3) 817M40 BS 970 (Part 1) 817A42
Standard BS 970 (Part 3):1991 BS 970 (Part 1):1983
Category Alloy Steel Alloy Steel
C (%) 0.36-0.44 0.40-0.45
Si (%) 0.10-0.40 Not specified
Mn (%) 0.45-0.70 0.45-0.70
P (%) <=0.035 <=0.035
S (%) <=0.040 <=0.040
Cr (%) 1.00-1.40 1.00-1.40
Mo (%) 0.20-0.35 0.20-0.35
Ni (%) 1.30-1.70 1.30-1.70
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Typical Applications
BS 970 (Part 3) 817M40
High tensile shafts, gears, crankshafts
BS 970 (Part 1) 817A42
Through hardening steel for mechanical and allied engineering purposes; supplied in the hardened and tempered conditions of Table 6.
Key Differences
Can BS 970 (Part 3) 817M40 Be Substituted With BS 970 (Part 1) 817A42?
BS 970 (Part 3) 817M40 and BS 970 (Part 1) 817A42 overlap closely enough on chemistry and mechanical properties that BS 970 (Part 1) 817A42 is often considered as a substitute for BS 970 (Part 3) 817M40 in many applications. Always confirm the specific property range your application needs before substituting, and check with your supplier's mill certificate.
Forms & Sizes Available on M-EX
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)
BS 970 (Part 1) 817A42
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On M-EX Right Now
BS 970 (Part 3) 817M40
2 active listings and RFQs →
BS 970 (Part 1) 817A42
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Frequently Asked Questions
What is the difference between BS 970 (Part 3) 817M40 and BS 970 (Part 1) 817A42?
BS 970 (Part 3) 817M40 specifies Si which is not specified for BS 970 (Part 1) 817A42.
Can BS 970 (Part 3) 817M40 be substituted with BS 970 (Part 1) 817A42?
BS 970 (Part 3) 817M40 and BS 970 (Part 1) 817A42 overlap closely enough on chemistry and mechanical properties that BS 970 (Part 1) 817A42 is often considered as a substitute for BS 970 (Part 3) 817M40 in many applications. Always confirm the specific property range your application needs before substituting, and check with your supplier's mill certificate.