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UNI 7846 18CrMo4 vs GB/T 3077 12Cr2Ni4A

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

UNI 7846 18CrMo4 (UNI 7846:1978) and GB/T 3077 12Cr2Ni4A (GB/T 3077-2015) are both steel grades. Both fall under the Alloy Steel category. UNI 7846 18CrMo4 is typically used for used in gears, shafts, pinions, crankshafts, axles, and heavy machinery components., while GB/T 3077 12Cr2Ni4A is commonly used for used for gears, shafts, pinions, aircraft parts, heavy-duty bearings, and transmission components.. UNI 7846 18CrMo4 is defined under Ente Nazionale Italiano di Unificazione (UNI), originating from Italy, while GB/T 3077 12Cr2Ni4A is defined under Guobiao Standards (GB/T), originating from China.

As per chemical composition, UNI 7846 18CrMo4 vs GB/T 3077 12Cr2Ni4A is a 57.2% match. As per mechanical properties, the match is 0%. Combined, this makes them a minimal match overall at 35%.

Frequently Compared With UNI 7846 18CrMo4:
UNI 11234 100Cr6 NF A35-565 100C6 GOST 4543 12HN3A IS 4367 07Cr4Mo6 IS 1570 (Part 4) 103Cr6 IS 1570 (Part 4) 105Cr5 IS 4367 10Cr9Mo10 IS 1570 (Part 7) 10Cr36Mo10H IS 1570 (Part 4) 103Cr4 IS 1570 (Part 4) 07Cr4Mo6 IS 1570 (Part 4) 10Cr20Mo6 EN 10028-2 10CrMo9-10
Match Breakdown
CHEMISTRY MATCH
57.2%
MECHANICAL MATCH
0%
OVERALL
35%
Specifications
Property UNI 7846 18CrMo4 GB/T 3077 12Cr2Ni4A
Standard UNI 7846:1978 GB/T 3077-2015
Category Alloy Steel Alloy Steel
C (%) 0.15-0.21 0.10-0.15
Si (%) 0.15-0.40 0.17-0.37
Mn (%) 0.60-0.90 0.30-0.60
Cr (%) 0.90-1.20 1.25-1.65
Mo (%) 0.15-0.30 Not specified
P (%) 0.035 max 0.025 max
S (%) 0.035 max 0.025 max
Ni (%) Not specified 3.25-3.75
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Mechanical Properties
Property UNI 7846 18CrMo4 GB/T 3077 12Cr2Ni4A
Tensile Strength 700-900 MPa 980-1180 MPa
Yield Strength 540 MPa min 785-980 MPa
Elongation 14% min 10-14%
Hardness 200-260 HB 58-62 HRC (case)
Typical Applications
UNI 7846 18CrMo4
Used in gears, shafts, pinions, crankshafts, axles, and heavy machinery components.
GB/T 3077 12Cr2Ni4A
Used for gears, shafts, pinions, aircraft parts, heavy-duty bearings, and transmission components.
Key Differences
Can UNI 7846 18CrMo4 Be Substituted With GB/T 3077 12Cr2Ni4A?
UNI 7846 18CrMo4 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
UNI 7846 18CrMo4
Round Bar → (2 listings)
Diameter: 50–50 mm (1.97–1.97 in)
Length: 5200–5400 mm (204.72–212.6 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
UNI 7846 18CrMo4
2 active listings and RFQs →
GB/T 3077 12Cr2Ni4A
2 active listings and RFQs →
Frequently Asked Questions
What is the difference between UNI 7846 18CrMo4 and GB/T 3077 12Cr2Ni4A?
UNI 7846 18CrMo4 specifies Mo which is not specified for GB/T 3077 12Cr2Ni4A. GB/T 3077 12Cr2Ni4A specifies Ni which is not specified for UNI 7846 18CrMo4.
Can UNI 7846 18CrMo4 be substituted with GB/T 3077 12Cr2Ni4A?
UNI 7846 18CrMo4 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.