Minimal Match — 35% match
based on chemical composition and mechanical property overlap.
AISI 4340 and GOST 4543 12HN3A (GOST 4543-2016) are both steel grades.
Both fall under the Alloy Steel category.
AISI 4340 is typically used for aircraft parts, heavy duty gears, crankshafts, high tensile bolts, while GOST 4543 12HN3A is commonly used for used for gears, pinions, crankshafts, aircraft parts, and transmission components..
AISI 4340 is defined under AISI (United States).
As per chemical composition, AISI 4340 vs GOST 4543 12HN3A is a 64.7% match.
As per mechanical properties, the match is 0%.
Combined, this makes them a minimal match overall at 35%.
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Mechanical Properties
Property
AISI 4340
GOST 4543 12HN3A
Condition
Quenched & Tempered
Not specified
Tensile Strength
1000–1200 MPa
850-1050 MPa
Yield Strength
≥830 MPa
685 MPa min
Elongation
≥12%
11% min
Hardness
285–341 HB
58-62 HRC (case)
Typical Applications
AISI 4340
Aircraft parts, heavy duty gears, crankshafts, high tensile bolts
GOST 4543 12HN3A
Used for gears, pinions, crankshafts, aircraft parts, and transmission components.
Key Differences
AISI 4340 specifies Mo which is not specified for GOST 4543 12HN3A.
Can AISI 4340 Be Substituted With GOST 4543 12HN3A?
AISI 4340 and GOST 4543 12HN3A 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.
What is the difference between AISI 4340 and GOST 4543 12HN3A?
AISI 4340 specifies Mo which is not specified for GOST 4543 12HN3A.
Can AISI 4340 be substituted with GOST 4543 12HN3A?
AISI 4340 and GOST 4543 12HN3A 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.