17-4PH vs 303: 46% composition overlap. Significantly different materials serving different application areas.
17-4PH vs 303
Side-by-side chemical composition and mechanical property comparison.
Overview
17-4PH
1.4542
The most widely used precipitation-hardening stainless steel. Combines high strength (up to 1310 MPa UTS) with corrosion resistance comparable to 304. Delivered solution-annealed and hardened by simple low-temperature aging. Used in aerospace, medical, oil & gas, and nuclear applications.
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.
| 17-4PH | 303 | |
|---|---|---|
| Material Number | 1.4542 | 1.4305 |
| Category | Stainless Steel | Stainless Steel |
| Standard | EN 10088-3 | EN 10088-3 |
Chemical composition (wt%)
| Element | 17-4PH | 303 | Overlap |
|---|---|---|---|
| C | 0–0.07% | 0–0.1% | OK |
| Si | 0–0.7% | 0–1% | OK |
| Mn | 0–1.5% | 0–2% | OK |
| P | 0–0.04% | 0–0.045% | OK |
Mechanical properties
| Property | 17-4PH | 303 | Unit |
|---|---|---|---|
| tensile_strength | ≥ 1310 | 500–750 | MPa |
| yield_strength | ≥ 1170 | ≥ 190 | MPa |
| elongation | ≥ 10 | ≥ 35 | % |
Compatibility Assessment
17-4PH and 303 have significantly different compositions (46% overlap). These materials are not interchangeable and serve different application areas.
Automated assessment based on composition analysis
Frequently Asked Questions
Is 17-4PH the same as 303?
17-4PH and 303 have a 46% composition overlap. They are generally not directly interchangeable.
Can I replace 17-4PH with 303?
Generally not recommended. The compositions differ significantly (46% overlap). These materials have different alloying concepts and are intended for different applications.
What is the difference between 17-4PH and 303?
The main differences are in the following elements: S, Cr, Ni. 17-4PH is a Stainless Steel grade, while 303 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.