317L / X2CrNiMo18-15-4 vs 316L: Same family — 317L has ~50% more Mo for better pitting resistance
317L / X2CrNiMo18-15-4 vs 316L
Side-by-side chemical composition and mechanical property comparison.
Overview
317L / X2CrNiMo18-15-4
1.4438
Low-carbon austenitic with 3-4% Mo — higher Mo than 316L (2-3%). Better pitting and crevice corrosion resistance (PREN ~30 vs ~25). Used in aggressive chemical environments where 316L is borderline: pharmaceutical, dye production, and organic acid processing.
316L
1.4404
Low-carbon austenitic stainless steel with molybdenum addition. Superior corrosion resistance to 304, especially against chlorides and pitting. Standard choice for chemical processing, marine, medical implants, and pharmaceutical equipment.
| 317L / X2CrNiMo18-15-4 | 316L | |
|---|---|---|
| Material Number | 1.4438 | 1.4404 |
| Category | Stainless Steel | Stainless Steel |
| Standard | EN 10088-2 | EN 10088-2 |
Chemical composition (wt%)
| Element | 317L / X2CrNiMo18-15-4 | 316L | Overlap |
|---|---|---|---|
| C | 0–0.03% | 0–0.03% | OK |
| Si | 0–1% | 0–1% | OK |
| Mn | 0–2% | 0–2% | OK |
| P | — | 0–0.045% | — |
Mechanical properties
| Property | 317L / X2CrNiMo18-15-4 | 316L | Unit |
|---|---|---|---|
| tensile_strength | 500–700 | 520–680 | MPa |
| yield_strength | ≥ 200 | ≥ 220 | MPa |
| elongation | ≥ 40 | ≥ 40 | % |
Compatibility Assessment
317L has 3-4% Mo (vs 2-3%) giving PREN ~30 vs ~25. Also higher Ni (13-16% vs 10-14%). Costs ~20-30% more. Choose 317L when 316L shows borderline pitting in chloride environments.
Frequently Asked Questions
Is 317L / X2CrNiMo18-15-4 the same as 316L?
317L / X2CrNiMo18-15-4 and 316L have a 80% composition overlap. Same family — 317L has ~50% more Mo for better pitting resistance
Can I replace 317L / X2CrNiMo18-15-4 with 316L?
In many cases, yes. The compositions overlap significantly (80%). However, always verify mechanical property requirements and heat treatment compatibility for your specific application.
What is the difference between 317L / X2CrNiMo18-15-4 and 316L?
The main differences are in the following elements: Cr, Mo, Ni. 317L / X2CrNiMo18-15-4 is a Stainless Steel grade, while 316L 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.
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