303 vs X8CrNiS18-9: 100% composition overlap. Very similar materials, likely interchangeable for most applications.
303 vs X8CrNiS18-9
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.
X8CrNiS18-9
1.4305
THE free-cutting austenitic stainless — AISI 303. Sulfur 0.15-0.35% for short-breaking chips and excellent machinability. Not weldable (hot cracking risk from S). Reduced corrosion resistance vs 304 due to sulfide inclusions. Used for high-volume CNC screw machine production of fittings, shafts, bushings, valves, and any turned stainless part where machining cost dominates.
| 303 | X8CrNiS18-9 | |
|---|---|---|
| Material Number | 1.4305 | 1.4305 |
| Category | Stainless Steel | Stainless Steel |
| Standard | EN 10088-3 | EN 10088-3 |
Chemical composition (wt%)
| Element | 303 | X8CrNiS18-9 | Overlap |
|---|---|---|---|
| C | 0–0.1% | 0–0.1% | OK |
| Si | 0–1% | 0–1% | OK |
| Mn | 0–2% | 0–2% | OK |
| P | 0–0.045% | — | — |
Mechanical properties
| Property | 303 | X8CrNiS18-9 | Unit |
|---|---|---|---|
| tensile_strength | 500–750 | 500–750 | MPa |
| yield_strength | ≥ 190 | ≥ 190 | MPa |
| elongation | ≥ 35 | ≥ 35 | % |
Compatibility Assessment
303 and X8CrNiS18-9 have very similar compositions (100% overlap) and are likely interchangeable for most applications. Verify mechanical properties for your specific use case.
Automated assessment based on composition analysis
Frequently Asked Questions
Is 303 the same as X8CrNiS18-9?
303 and X8CrNiS18-9 have a 100% composition overlap. For most purposes, they can be considered similar.
Can I replace 303 with X8CrNiS18-9?
In many cases, yes. The compositions overlap significantly (100%). However, always verify mechanical property requirements and heat treatment compatibility for your specific application.
What is the difference between 303 and X8CrNiS18-9?
The main differences are in the following elements: overall alloying content. 303 is a Stainless Steel grade, while X8CrNiS18-9 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.