Strong Match — 98.3% match
based on chemical composition and mechanical property overlap.
AISI 4340 and SAE J404 4340 (SAE J404:2009) 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 SAE J404 4340 is commonly used for aircraft parts, heavy duty gears, crankshafts.
AISI 4340 is defined under AISI, originating from United States, while SAE J404 4340 is defined under SAE International, originating from United States.
As per chemical composition, AISI 4340 vs SAE J404 4340 is a 98.3% match.
Mechanical property data is not available for both grades, so this factor could not be scored.
Combined, this makes them a strong match overall at 98.3%.
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
SAE J404 4340
Condition
Quenched & Tempered
Not specified
Tensile Strength
1000–1200 MPa
Not specified
Yield Strength
≥830 MPa
Not specified
Elongation
≥12%
Not specified
Hardness
285–341 HB
Not specified
Typical Applications
AISI 4340
Aircraft parts, heavy duty gears, crankshafts, high tensile bolts
SAE J404 4340
Aircraft parts, heavy duty gears, crankshafts
Key Differences
SAE J404 4340 specifies P, S which are not specified for AISI 4340.
Can AISI 4340 Be Substituted With SAE J404 4340?
AISI 4340 and SAE J404 4340 overlap closely enough on chemistry and mechanical properties that SAE J404 4340 is often considered as a substitute for AISI 4340 in many applications. Always confirm the specific property range your application needs before substituting, and check with your supplier's mill certificate.
What is the difference between AISI 4340 and SAE J404 4340?
SAE J404 4340 specifies P, S which are not specified for AISI 4340.
Can AISI 4340 be substituted with SAE J404 4340?
AISI 4340 and SAE J404 4340 overlap closely enough on chemistry and mechanical properties that SAE J404 4340 is often considered as a substitute for AISI 4340 in many applications. Always confirm the specific property range your application needs before substituting, and check with your supplier's mill certificate.