Related Material — 64.5% match
based on chemical composition and mechanical property overlap.
ASTM A681 P21 (ASTM A681:2008) and GB/T 3077 20CrNi3 (GB/T 3077:2015) are both steel grades.
ASTM A681 P21 is classified under Tool & Die Steels, while GB/T 3077 20CrNi3 is classified under Alloy Steel — a different category, which is worth noting alongside the chemistry match below.
ASTM A681 P21 is typically used for tools, dies and fixtures (clause 1.2), while GB/T 3077 20CrNi3 is commonly used for hot-rolled or forged structural alloy steel bars.
ASTM A681 P21 is defined under ASTM International, originating from United States, while GB/T 3077 20CrNi3 is defined under Guobiao Standards (GB/T), originating from China.
As per chemical composition, ASTM A681 P21 vs GB/T 3077 20CrNi3 is a 64.5% match.
Mechanical property data is not available for both grades, so this factor could not be scored.
Combined, this makes them a related material overall at 64.5%.
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Mechanical Properties
Property
ASTM A681 P21
GB/T 3077 20CrNi3
Tensile Strength
Not specified
>=930 MPa
Yield Strength
Not specified
>=735 MPa
Elongation
Not specified
>=11%
Hardness
Not specified
<=241 HB
Condition
Not specified
Quenched and tempered, test sample 25 mm; hardness is for bars delivered annealed or high temperature tempered
Typical Applications
ASTM A681 P21
Tools, dies and fixtures (clause 1.2)
GB/T 3077 20CrNi3
Hot-rolled or forged structural alloy steel bars
Key Differences
Different category: ASTM A681 P21 is Tool & Die Steels, GB/T 3077 20CrNi3 is Alloy Steel.
ASTM A681 P21 specifies V, Al which are not specified for GB/T 3077 20CrNi3.
GB/T 3077 20CrNi3 specifies Cu which is not specified for ASTM A681 P21.
Can ASTM A681 P21 Be Substituted With GB/T 3077 20CrNi3?
ASTM A681 P21 and GB/T 3077 20CrNi3 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 ASTM A681 P21 and GB/T 3077 20CrNi3?
Different category: ASTM A681 P21 is Tool & Die Steels, GB/T 3077 20CrNi3 is Alloy Steel. ASTM A681 P21 specifies V, Al which are not specified for GB/T 3077 20CrNi3. GB/T 3077 20CrNi3 specifies Cu which is not specified for ASTM A681 P21.
Can ASTM A681 P21 be substituted with GB/T 3077 20CrNi3?
ASTM A681 P21 and GB/T 3077 20CrNi3 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.