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