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BS 970 (Part 1) 709M40 vs BS 970 (Part 3) 709M40

Strong Match — 92.9% match based on chemical composition and mechanical property overlap.

BS 970 (Part 1) 709M40 (BS 970 (Part 1):1991) and BS 970 (Part 3) 709M40 (BS 970 (Part 3):1991) are both steel grades. Both fall under the Alloy Steel category. BS 970 (Part 1) 709M40 is typically used for used for aircraft parts, heavy-duty gears, transmission shafts, connecting rods, crankshafts, and engineering fasteners., while BS 970 (Part 3) 709M40 is commonly used for bright cold finished bars (cold drawn, turned or precision ground) for general engineering purposes, in straight lengths; alloy direct hardening steel (table 16). BS 970 (Part 1) 709M40 is defined under British Standards (BS), originating from United Kingdom, while BS 970 (Part 3) 709M40 is defined under British Standards (BS), originating from United Kingdom.

As per chemical composition, BS 970 (Part 1) 709M40 vs BS 970 (Part 3) 709M40 is a 92.9% 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 92.9%.

Frequently Compared With BS 970 (Part 1) 709M40:
UNI 11234 100Cr6 NF A35-565 100C6 GB/T 3077 12Cr2Ni4A GOST 4543 12HN3A IS 1570 (Part 4) 07Cr4Mo6 IS 1570 (Part 4) 10Cr20Mo6 IS 4367 07Cr4Mo6 IS 1570 (Part 4) 105Cr5 IS 4367 10Cr9Mo10 IS 1570 (Part 4) 103Cr4 IS 1570 (Part 7) 10Cr36Mo10H IS 1570 (Part 4) 103Cr6
Match Breakdown
CHEMISTRY MATCH
92.9%
MECHANICAL MATCH
No shared data
OVERALL
92.9%
Specifications
Property BS 970 (Part 1) 709M40 BS 970 (Part 3) 709M40
Standard BS 970 (Part 1):1991 BS 970 (Part 3):1991
Category Alloy Steel Alloy Steel
C (%) 0.36-0.44 0.36-0.44
Mn (%) 0.70-1.00 0.70-1.00
Cr (%) 0.90-1.20 0.90-1.20
Mo (%) 0.25-0.35 0.25-0.35
Si (%) Not specified 0.10-0.40
P (%) Not specified <=0.035
S (%) Not specified <=0.040
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 1) 709M40
Used for aircraft parts, heavy-duty gears, transmission shafts, connecting rods, crankshafts, and engineering fasteners.
BS 970 (Part 3) 709M40
Bright cold finished bars (cold drawn, turned or precision ground) for general engineering purposes, in straight lengths; alloy direct hardening steel (Table 16)
Key Differences
Can BS 970 (Part 1) 709M40 Be Substituted With BS 970 (Part 3) 709M40?
BS 970 (Part 1) 709M40 and BS 970 (Part 3) 709M40 overlap closely enough on chemistry and mechanical properties that BS 970 (Part 3) 709M40 is often considered as a substitute for BS 970 (Part 1) 709M40 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 1) 709M40
Round Bar → (2 listings)
Diameter: 50–50 mm (1.97–1.97 in)
Length: 6600–6800 mm (259.84–267.72 in)
BS 970 (Part 3) 709M40
No active listings currently.
On M-EX Right Now
BS 970 (Part 1) 709M40
2 active listings and RFQs →
BS 970 (Part 3) 709M40
0 active listings and RFQs →
Frequently Asked Questions
What is the difference between BS 970 (Part 1) 709M40 and BS 970 (Part 3) 709M40?
BS 970 (Part 3) 709M40 specifies Si, P, S which are not specified for BS 970 (Part 1) 709M40.
Can BS 970 (Part 1) 709M40 be substituted with BS 970 (Part 3) 709M40?
BS 970 (Part 1) 709M40 and BS 970 (Part 3) 709M40 overlap closely enough on chemistry and mechanical properties that BS 970 (Part 3) 709M40 is often considered as a substitute for BS 970 (Part 1) 709M40 in many applications. Always confirm the specific property range your application needs before substituting, and check with your supplier's mill certificate.