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GB/T 3077 30Mn2 vs GB/T 3077 40B

Close Alternative — 84.9% match based on chemical composition and mechanical property overlap.

GB/T 3077 30Mn2 (GB/T 3077:2015) and GB/T 3077 40B (GB/T 3077:2015) are both steel grades. Both fall under the Alloy Steel category. GB/T 3077 30Mn2 is typically used for hot-rolled or forged structural alloy steel bars, while GB/T 3077 40B is commonly used for hot-rolled or forged structural alloy steel bars. GB/T 3077 30Mn2 is defined under Guobiao Standards (GB/T), originating from China, while GB/T 3077 40B is defined under Guobiao Standards (GB/T), originating from China.

As per chemical composition, GB/T 3077 30Mn2 vs GB/T 3077 40B is a 80.3% match. As per mechanical properties, the match is 100%. Combined, this makes them a close alternative overall at 84.9%.

Frequently Compared With GB/T 3077 30Mn2:
UNI 11234 100Cr6 NF A35-565 100C6 IS 1570 (Part 4) 103Cr4 IS 1570 (Part 4) 10Cr20Mo6 IS 1570 (Part 7) 10Cr36Mo10H EN 10028-2 10CrMo9-10 IS 1570 (Part 4) 10Mo6 IS 4367 07Cr4Mo6 IS 1570 (Part 4) 07Cr4Mo6 IS 1570 (Part 4) 103Cr6 IS 1570 (Part 4) 105Cr5 IS 4367 10Cr9Mo10
Match Breakdown
CHEMISTRY MATCH
80.3%
MECHANICAL MATCH
100%
OVERALL
84.9%
Specifications
Property GB/T 3077 30Mn2 GB/T 3077 40B
Standard GB/T 3077:2015 GB/T 3077:2015
Category Alloy Steel Alloy Steel
C (%) 0.27-0.34 0.37-0.44
Si (%) 0.17-0.37 0.17-0.37
Mn (%) 1.40-1.80 0.60-0.90
P (%) <=0.030 <=0.030
S (%) <=0.030 <=0.030
Cu (%) <=0.30 <=0.30
B (%) Not specified 0.0008-0.0035
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Mechanical Properties
Property GB/T 3077 30Mn2 GB/T 3077 40B
Tensile Strength >=785 MPa >=785 MPa
Yield Strength >=635 MPa >=635 MPa
Elongation >=12% >=12%
Hardness <=207 HB <=207 HB
Condition Quenched and tempered, test sample 25 mm; hardness is for bars delivered annealed or high temperature tempered Quenched and tempered, test sample 25 mm; hardness is for bars delivered annealed or high temperature tempered
Typical Applications
GB/T 3077 30Mn2
Hot-rolled or forged structural alloy steel bars
GB/T 3077 40B
Hot-rolled or forged structural alloy steel bars
Key Differences
Can GB/T 3077 30Mn2 Be Substituted With GB/T 3077 40B?
GB/T 3077 30Mn2 and GB/T 3077 40B are a close alternative rather than a direct substitute. Some properties overlap well, but check the specific chemistry and mechanical rows above against your application's requirements before treating them as interchangeable.
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GB/T 3077 30Mn2
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GB/T 3077 40B
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Frequently Asked Questions
What is the difference between GB/T 3077 30Mn2 and GB/T 3077 40B?
GB/T 3077 40B specifies B which is not specified for GB/T 3077 30Mn2.
Can GB/T 3077 30Mn2 be substituted with GB/T 3077 40B?
GB/T 3077 30Mn2 and GB/T 3077 40B are a close alternative rather than a direct substitute. Some properties overlap well, but check the specific chemistry and mechanical rows above against your application's requirements before treating them as interchangeable.