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

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

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

As per chemical composition, GB/T 3077 40B vs GB/T 3077 30Mn2 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 40B:
IS 4367 07Cr4Mo6 IS 1570 (Part 7) 10Mo6H IS 1570 (Part 4) 07Cr4Mo6 NF A35-565 100C6 UNI 11234 100Cr6 IS 1570 (Part 4) 103Cr4 IS 1570 (Part 4) 103Cr6 IS 1570 (Part 4) 105Cr5 IS 1570 (Part 4) 10Cr20Mo6 IS 4367 10Cr9Mo10 IS 1570 (Part 7) 10Cr36Mo10H EN 10028-2 10CrMo9-10
Match Breakdown
CHEMISTRY MATCH
80.3%
MECHANICAL MATCH
100%
OVERALL
84.9%
Specifications
Property GB/T 3077 40B GB/T 3077 30Mn2
Standard GB/T 3077:2015 GB/T 3077:2015
Category Alloy Steel Alloy Steel
C (%) 0.37-0.44 0.27-0.34
Si (%) 0.17-0.37 0.17-0.37
Mn (%) 0.60-0.90 1.40-1.80
B (%) 0.0008-0.0035 Not specified
P (%) <=0.030 <=0.030
S (%) <=0.030 <=0.030
Cu (%) <=0.30 <=0.30
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 40B GB/T 3077 30Mn2
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 40B
Hot-rolled or forged structural alloy steel bars
GB/T 3077 30Mn2
Hot-rolled or forged structural alloy steel bars
Key Differences
Can GB/T 3077 40B Be Substituted With GB/T 3077 30Mn2?
GB/T 3077 40B and GB/T 3077 30Mn2 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 40B
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GB/T 3077 30Mn2
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Frequently Asked Questions
What is the difference between GB/T 3077 40B and GB/T 3077 30Mn2?
GB/T 3077 40B specifies B which is not specified for GB/T 3077 30Mn2.
Can GB/T 3077 40B be substituted with GB/T 3077 30Mn2?
GB/T 3077 40B and GB/T 3077 30Mn2 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.