303 vs 440C / X105CrMo17: 45% composition overlap. Significantly different materials serving different application areas.
303 vs 440C / X105CrMo17
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.
440C / X105CrMo17
1.4125
Highest-hardness standard martensitic stainless steel. Achieves 57-60 HRC — the hardest commonly available stainless grade. Excellent wear resistance from chromium carbides. Used for bearings, races, valve components, surgical instruments, high-end cutlery, and precision molds.
| 303 | 440C / X105CrMo17 | |
|---|---|---|
| Material Number | 1.4305 | 1.4125 |
| Category | Stainless Steel | Stainless Steel |
| Standard | EN 10088-3 | EN 10088-3 |
Chemical composition (wt%)
| Element | 303 | 440C / X105CrMo17 | Overlap |
|---|---|---|---|
| C | 0–0.1% | 0.95–1.2% | 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 | 440C / X105CrMo17 | Unit |
|---|---|---|---|
| tensile_strength | 500–750 | ≥ 690 | MPa |
| yield_strength | ≥ 190 | ≥ 440 | MPa |
| elongation | ≥ 35 | — | % |
Compatibility Assessment
303 and 440C / X105CrMo17 have significantly different compositions (45% 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 440C / X105CrMo17?
303 and 440C / X105CrMo17 have a 45% composition overlap. They are generally not directly interchangeable.
Can I replace 303 with 440C / X105CrMo17?
Generally not recommended. The compositions differ significantly (45% overlap). These materials have different alloying concepts and are intended for different applications.
What is the difference between 303 and 440C / X105CrMo17?
The main differences are in the following elements: C, S, Cr. 303 is a Stainless Steel grade, while 440C / X105CrMo17 is a Stainless Steel grade.
Related Comparisons
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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.