303 vs SUS420J2: 34% composition overlap. Significantly different materials serving different application areas.
303 vs SUS420J2
Side-by-side chemical composition and mechanical property comparison.
Overview
303
1.4305
Free-machining austenitic stainless steel — the most machinable of all austenitic grades. 0.15-0.35% S (as MnS inclusions) provides excellent chip-breaking. Trade-off: lower corrosion resistance than 304, poor weldability (hot cracking risk), and not suitable for cold forming. Used for high-volume automatic lathe parts: fittings, valves, screws, shafts, and precision components.
SUS420J2
Japanese martensitic stainless steel — the higher-carbon variant of the 420 family (C 0.26-0.40%). Achieves HRC 50-55 after heat treatment. Very good corrosion resistance for a martensitic grade. THE budget knife/cutlery steel worldwide. Also used for surgical instruments, haircutting scissors, and industrial blades. ≈ EN X30Cr13 (1.4028) / Chinese 3Cr13.
| 303 | SUS420J2 | |
|---|---|---|
| Material Number | 1.4305 | — |
| Category | Stainless Steel | Stainless Steel |
| Standard | EN 10088-3 | JIS G4303 |
Chemical composition (wt%)
| Element | 303 | SUS420J2 | Overlap |
|---|---|---|---|
| C | 0–0.1% | 0.26–0.4% | No overlap |
| Si | 0–1% | 0–1% | OK |
| Mn | 0–2% | 0–1% | OK |
| P | 0–0.045% | 0–0.04% | OK |
Mechanical properties
| Property | 303 | SUS420J2 | Unit |
|---|---|---|---|
| tensile_strength | 500–750 | 620–700 | MPa |
| yield_strength | ≥ 190 | 340–400 | MPa |
| elongation | ≥ 35 | 12–18 | % |
Compatibility Assessment
303 and SUS420J2 have significantly different compositions (34% overlap). These materials are not interchangeable and serve different application areas.
Automated assessment based on composition analysis
Frequently Asked Questions
Is 303 the same as SUS420J2?
303 and SUS420J2 have a 34% composition overlap. They are generally not directly interchangeable.
Can I replace 303 with SUS420J2?
Generally not recommended. The compositions differ significantly (34% overlap). These materials have different alloying concepts and are intended for different applications.
What is the difference between 303 and SUS420J2?
The main differences are in the following elements: C, S, Cr, Ni. 303 is a Stainless Steel grade, while SUS420J2 is a Stainless Steel grade.
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Data provided for reference only. Always verify against the applicable specification for critical applications.
All data is for reference only. Equivalents indicate similarity, not identity. Always verify against the applicable specification for safety-critical applications. materialref.com accepts no liability for decisions based on this data.