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JIS G4103 SNCM439 vs SAE J404 4340

Strong Match — 85.7% match based on chemical composition and mechanical property overlap.

JIS G4103 SNCM439 (JIS G4103:1979) and SAE J404 4340 (SAE J404:2000) are both steel grades. Both fall under the Alloy Steel category. JIS G4103 SNCM439 is typically used for crankshafts, gears, heavy duty shafts, aircraft components, while SAE J404 4340 is commonly used for chemistry-only alloy steel grade; see the composition notes for product scope. JIS G4103 SNCM439 is defined under Japanese Industrial Standards (JIS), originating from Japan, while SAE J404 4340 is defined under SAE International, originating from United States.

As per chemical composition, JIS G4103 SNCM439 vs SAE J404 4340 is a 85.7% 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 85.7%.

Frequently Compared With JIS G4103 SNCM439:
GOST 4543 12HN3A NF A35-565 100C6 UNI 11234 100Cr6 GB/T 3077 12Cr2Ni4A IS 1570 (Part 4) 07Cr4Mo6 IS 4367 07Cr4Mo6 IS 1570 (Part 4) 103Cr4 IS 1570 (Part 4) 10Cr20Mo6 IS 1570 (Part 4) 105Cr5 IS 1570 (Part 4) 103Cr6 IS 1570 (Part 7) 10Cr36Mo10H IS 4367 10Cr9Mo10
Match Breakdown
CHEMISTRY MATCH
85.7%
MECHANICAL MATCH
No shared data
OVERALL
85.7%
Specifications
Property JIS G4103 SNCM439 SAE J404 4340
Standard JIS G4103:1979 SAE J404:2000
Category Alloy Steel Alloy Steel
C (%) 0.36–0.43 0.38-0.43
Si (%) 0.15–0.35 0.15-0.35
Mn (%) 0.60–0.90 0.60-0.80
Cr (%) 0.60–1.00 0.70-0.90
Mo (%) 0.15–0.30 0.20-0.30
Ni (%) 1.60–2.00 1.65-2.00
P (%) Not specified <=0.030
S (%) Not specified <=0.040
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Mechanical Properties
Property JIS G4103 SNCM439 SAE J404 4340
Tensile Strength ≥980 MPa Not specified
Yield Strength ≥835 MPa Not specified
Elongation ≥12% Not specified
Hardness 293–352 HB Not specified
Typical Applications
JIS G4103 SNCM439
Crankshafts, gears, heavy duty shafts, aircraft components
SAE J404 4340
Chemistry-only alloy steel grade; see the composition notes for product scope
Key Differences
Can JIS G4103 SNCM439 Be Substituted With SAE J404 4340?
JIS G4103 SNCM439 and SAE J404 4340 overlap closely enough on chemistry and mechanical properties that SAE J404 4340 is often considered as a substitute for JIS G4103 SNCM439 in many applications. Always confirm the specific property range your application needs before substituting, and check with your supplier's mill certificate.
Forms & Sizes Available on M-EX
JIS G4103 SNCM439
Round Bar → (3 listings)
Diameter: 50–50 mm (1.97–1.97 in)
Length: 4900–5800 mm (192.91–228.35 in)
SAE J404 4340
No active listings currently.
On M-EX Right Now
JIS G4103 SNCM439
3 active listings and RFQs →
SAE J404 4340
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Frequently Asked Questions
What is the difference between JIS G4103 SNCM439 and SAE J404 4340?
SAE J404 4340 specifies P, S which are not specified for JIS G4103 SNCM439.
Can JIS G4103 SNCM439 be substituted with SAE J404 4340?
JIS G4103 SNCM439 and SAE J404 4340 overlap closely enough on chemistry and mechanical properties that SAE J404 4340 is often considered as a substitute for JIS G4103 SNCM439 in many applications. Always confirm the specific property range your application needs before substituting, and check with your supplier's mill certificate.