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ASTM A681 A6 vs AISI 4140

Related Material — 65% match based on chemical composition and mechanical property overlap.

ASTM A681 A6 (ASTM A681:2008) and AISI 4140 are both steel grades. ASTM A681 A6 is classified under Tool & Die Steels, while AISI 4140 is classified under Alloy Steel — a different category, which is worth noting alongside the chemistry match below. ASTM A681 A6 is typically used for tools, dies and fixtures (clause 1.2), while AISI 4140 is commonly used for gears, shafts, dies, bolts, crankshafts, tooling. ASTM A681 A6 is defined under ASTM International, originating from United States, while AISI 4140 is defined under AISI, originating from United States.

As per chemical composition, ASTM A681 A6 vs AISI 4140 is a 67.2% match. As per mechanical properties, the match is 100%. Combined, this makes them a related material overall at 65%.

Frequently Compared With ASTM A681 A6:
GB/T 1299 3Cr2W8V DIN EN ISO 4957 1.2344 EN ISO 4957 1.2316 DIN EN ISO 4957 1.2379 IS 1570 (Part 6) 103T3 IS 1570 (Part 6) 118T3 IS 1570 (Part 6) 133T3 GB/T 1299 4Cr5MoSiV1 GB/T 1299 4Cr5MoSiV EN ISO 683-17 100Cr6 GOST 5950 3H2W8F GOST 5950 4H5MFS
Match Breakdown
CHEMISTRY MATCH
67.2%
MECHANICAL MATCH
100%
OVERALL
65%
Specifications
Property ASTM A681 A6 AISI 4140
Standard ASTM A681:2008 AISI
Category Tool & Die Steels Alloy Steel
C (%) 0.65-0.75 0.38–0.43
Mn (%) 1.80-2.50 0.75–1.00
P (%) <=0.030 ≤0.035
S (%) <=0.030 ≤0.040
Si (%) 0.10-0.70 0.15–0.35
Cr (%) 0.90-1.40 0.80–1.10
Mo (%) 0.90-1.40 0.15–0.25
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Mechanical Properties
Property ASTM A681 A6 AISI 4140
Hardness <=248 HB 248–302 HB
Condition Annealed (maximum Brinell hardness) Quenched & Tempered
Tensile Strength Not specified 850–1000 MPa
Yield Strength Not specified ≥680 MPa
Elongation Not specified ≥13%
Impact (Charpy) Not specified ≥54 J
Typical Applications
ASTM A681 A6
Tools, dies and fixtures (clause 1.2)
AISI 4140
Gears, shafts, dies, bolts, crankshafts, tooling
Key Differences
Can ASTM A681 A6 Be Substituted With AISI 4140?
ASTM A681 A6 and AISI 4140 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
ASTM A681 A6
No active listings currently.
AISI 4140
Round Bar → (3 listings)
Diameter: 50–50 mm (1.97–1.97 in)
Length: 5800–7000 mm (228.35–275.59 in)
On M-EX Right Now
ASTM A681 A6
0 active listings and RFQs →
AISI 4140
3 active listings and RFQs →
Frequently Asked Questions
What is the difference between ASTM A681 A6 and AISI 4140?
Different category: ASTM A681 A6 is Tool & Die Steels, AISI 4140 is Alloy Steel.
Can ASTM A681 A6 be substituted with AISI 4140?
ASTM A681 A6 and AISI 4140 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.