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NF A35-552 42CD4 vs BS 970 (Part 3) 709M40

Close Alternative — 84.5% match based on chemical composition and mechanical property overlap.

NF A35-552 42CD4 (NF A35-552:1986) and BS 970 (Part 3) 709M40 (BS 970 (Part 3):1991) are both steel grades. Both fall under the Alloy Steel category. NF A35-552 42CD4 is typically used for gears, shafts, crankshafts, high tensile 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). NF A35-552 42CD4 is defined under Association Francaise de Normalisation (NF), originating from France, while BS 970 (Part 3) 709M40 is defined under British Standards (BS), originating from United Kingdom.

As per chemical composition, NF A35-552 42CD4 vs BS 970 (Part 3) 709M40 is a 84.5% 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 84.5%.

Frequently Compared With NF A35-552 42CD4:
GOST 4543 12HN3A GB/T 3077 12Cr2Ni4A NF A35-565 100C6 UNI 11234 100Cr6 IS 1570 (Part 4) 103Cr4 IS 1570 (Part 4) 105Cr5 IS 1570 (Part 4) 10Cr20Mo6 IS 4367 07Cr4Mo6 IS 1570 (Part 4) 07Cr4Mo6 IS 1570 (Part 4) 103Cr6 IS 1570 (Part 7) 10Cr36Mo10H IS 4367 10Cr9Mo10
Match Breakdown
CHEMISTRY MATCH
84.5%
MECHANICAL MATCH
No shared data
OVERALL
84.5%
Specifications
Property NF A35-552 42CD4 BS 970 (Part 3) 709M40
Standard NF A35-552:1986 BS 970 (Part 3):1991
Category Alloy Steel Alloy Steel
C (%) 0.38–0.45 0.36-0.44
Si (%) 0.15–0.35 0.10-0.40
Mn (%) 0.60–0.90 0.70-1.00
Cr (%) 0.90–1.20 0.90-1.20
Mo (%) 0.15–0.30 0.25-0.35
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.
Mechanical Properties
Property NF A35-552 42CD4 BS 970 (Part 3) 709M40
Tensile Strength 900–1100 MPa Not specified
Yield Strength ≥700 MPa Not specified
Elongation ≥12% Not specified
Hardness 263–313 HB Not specified
Typical Applications
NF A35-552 42CD4
Gears, shafts, crankshafts, high tensile 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 NF A35-552 42CD4 Be Substituted With BS 970 (Part 3) 709M40?
NF A35-552 42CD4 and BS 970 (Part 3) 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
NF A35-552 42CD4
Round Bar → (3 listings)
Diameter: 50–50 mm (1.97–1.97 in)
Length: 5900–6800 mm (232.28–267.72 in)
BS 970 (Part 3) 709M40
No active listings currently.
On M-EX Right Now
NF A35-552 42CD4
3 active listings and RFQs →
BS 970 (Part 3) 709M40
0 active listings and RFQs →
Frequently Asked Questions
What is the difference between NF A35-552 42CD4 and BS 970 (Part 3) 709M40?
BS 970 (Part 3) 709M40 specifies P, S which are not specified for NF A35-552 42CD4.
Can NF A35-552 42CD4 be substituted with BS 970 (Part 3) 709M40?
NF A35-552 42CD4 and BS 970 (Part 3) 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.