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BS 970 EN30A vs BS 970 (Part 3) 637M17

Related Material — 67% match based on chemical composition and mechanical property overlap.

BS 970 EN30A (BS 970:1955) and BS 970 (Part 3) 637M17 (BS 970 (Part 3):1991) are both steel grades. Both fall under the Alloy Steel category. BS 970 EN30A is typically used for used for gears, aircraft components, transmission shafts, heavy-duty pinions, crankshafts, and high-strength fasteners., while BS 970 (Part 3) 637M17 is commonly used for bright cold finished bars (cold drawn, turned or precision ground) for general engineering purposes, in straight lengths; alloy case hardening steel (table 15). BS 970 EN30A is defined under British Standards (BS), originating from United Kingdom, while BS 970 (Part 3) 637M17 is defined under British Standards (BS), originating from United Kingdom.

As per chemical composition, BS 970 EN30A vs BS 970 (Part 3) 637M17 is a 67% 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 67%.

Frequently Compared With BS 970 EN30A:
UNI 11234 100Cr6 NF A35-565 100C6 GB/T 3077 12Cr2Ni4A GOST 4543 12HN3A IS 1570 (Part 4) 103Cr6 IS 4367 07Cr4Mo6 IS 1570 (Part 4) 07Cr4Mo6 IS 1570 (Part 4) 103Cr4 IS 1570 (Part 7) 10Cr36Mo10H IS 1570 (Part 4) 105Cr5 IS 1570 (Part 4) 10Cr20Mo6 IS 4367 10Cr9Mo10
Match Breakdown
CHEMISTRY MATCH
67%
MECHANICAL MATCH
No shared data
OVERALL
67%
Specifications
Property BS 970 EN30A BS 970 (Part 3) 637M17
Standard BS 970:1955 BS 970 (Part 3):1991
Category Alloy Steel Alloy Steel
C (%) 0.26-0.34 0.14-0.20
Si (%) 0.10-0.35 0.10-0.40
Mn (%) 0.40-0.60 0.60-0.90
Ni (%) 3.90-4.30 0.85-1.25
Cr (%) 1.10-1.40 0.60-1.00
S (%) <=0.050 <=0.05
P (%) <=0.050 <=0.04
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 EN30A BS 970 (Part 3) 637M17
Tensile Strength ≥1544 MPa (100 tons/sq in, converted) Not specified
Yield Strength ≥1313 MPa (85 tons/sq in, converted) Not specified
Elongation ≥10% Not specified
Hardness 444 HB Not specified
Condition Air hardened and tempered (lowest-strength condition of the standard) Not specified
Typical Applications
BS 970 EN30A
Used for gears, aircraft components, transmission shafts, heavy-duty pinions, crankshafts, and high-strength fasteners.
BS 970 (Part 3) 637M17
Bright cold finished bars (cold drawn, turned or precision ground) for general engineering purposes, in straight lengths; alloy case hardening steel (Table 15)
Can BS 970 EN30A Be Substituted With BS 970 (Part 3) 637M17?
BS 970 EN30A and BS 970 (Part 3) 637M17 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 EN30A
Round Bar → (2 listings)
Diameter: 50–50 mm (1.97–1.97 in)
Length: 6400–6600 mm (251.97–259.84 in)
BS 970 (Part 3) 637M17
No active listings currently.
On M-EX Right Now
BS 970 EN30A
2 active listings and RFQs →
BS 970 (Part 3) 637M17
0 active listings and RFQs →
Frequently Asked Questions
What is the difference between BS 970 EN30A and BS 970 (Part 3) 637M17?
Both grades share a similar composition profile; see the specification table above for the exact chemistry and mechanical property values.
Can BS 970 EN30A be substituted with BS 970 (Part 3) 637M17?
BS 970 EN30A and BS 970 (Part 3) 637M17 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.