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AISI 4340 vs GB/T 3077 12Cr2Ni4A

Minimal Match — 35% match based on chemical composition and mechanical property overlap.

AISI 4340 and GB/T 3077 12Cr2Ni4A (GB/T 3077-2015) 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 GB/T 3077 12Cr2Ni4A is commonly used for used for gears, shafts, pinions, aircraft parts, heavy-duty bearings, and transmission components.. AISI 4340 is defined under AISI, originating from United States, while GB/T 3077 12Cr2Ni4A is defined under Guobiao Standards (GB/T), originating from China.

As per chemical composition, AISI 4340 vs GB/T 3077 12Cr2Ni4A is a 56.1% match. As per mechanical properties, the match is 0%. Combined, this makes them a minimal match overall at 35%.

Frequently Compared With AISI 4340:
NF A35-565 100C6 UNI 11234 100Cr6 GOST 4543 12HN3A IS 1570 (Part 4) 103Cr4 IS 1570 (Part 4) 105Cr5 IS 4367 07Cr4Mo6 IS 1570 (Part 4) 103Cr6 IS 1570 (Part 4) 10Cr20Mo6 IS 1570 (Part 7) 10Cr36Mo10H IS 1570 (Part 4) 07Cr4Mo6 IS 4367 10Cr9Mo10 EN 10028-2 10CrMo9-10
Match Breakdown
CHEMISTRY MATCH
56.1%
MECHANICAL MATCH
0%
OVERALL
35%
Specifications
Property AISI 4340 GB/T 3077 12Cr2Ni4A
Standard AISI GB/T 3077-2015
Category Alloy Steel Alloy Steel
C (%) 0.38–0.43 0.10-0.15
Mn (%) 0.60–0.80 0.30-0.60
Cr (%) 0.70–0.90 1.25-1.65
Mo (%) 0.20–0.30 Not specified
Ni (%) 1.65–2.00 3.25-3.75
Si (%) 0.15–0.35 0.17-0.37
P (%) Not specified 0.025 max
S (%) Not specified 0.025 max
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 GB/T 3077 12Cr2Ni4A
Condition Quenched & Tempered Not specified
Tensile Strength 1000–1200 MPa 980-1180 MPa
Yield Strength ≥830 MPa 785-980 MPa
Elongation ≥12% 10-14%
Hardness 285–341 HB 58-62 HRC (case)
Typical Applications
AISI 4340
Aircraft parts, heavy duty gears, crankshafts, high tensile bolts
GB/T 3077 12Cr2Ni4A
Used for gears, shafts, pinions, aircraft parts, heavy-duty bearings, and transmission components.
Key Differences
Can AISI 4340 Be Substituted With GB/T 3077 12Cr2Ni4A?
AISI 4340 and GB/T 3077 12Cr2Ni4A 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
AISI 4340
Round Bar → (3 listings)
Diameter: 50–50 mm (1.97–1.97 in)
Length: 5900–6800 mm (232.28–267.72 in)
GB/T 3077 12Cr2Ni4A
Round Bar → (2 listings)
Diameter: 50–50 mm (1.97–1.97 in)
Length: 5000–6600 mm (196.85–259.84 in)
On M-EX Right Now
AISI 4340
3 active listings and RFQs →
GB/T 3077 12Cr2Ni4A
2 active listings and RFQs →
Frequently Asked Questions
What is the difference between AISI 4340 and GB/T 3077 12Cr2Ni4A?
AISI 4340 specifies Mo which is not specified for GB/T 3077 12Cr2Ni4A. GB/T 3077 12Cr2Ni4A specifies P, S which are not specified for AISI 4340.
Can AISI 4340 be substituted with GB/T 3077 12Cr2Ni4A?
AISI 4340 and GB/T 3077 12Cr2Ni4A 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.