1.4550 vs 1.4571 stainless steel: High temperature resistance
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High-temperature stainless steels are essential in industries such as petrochemical, thermal power, exhaust systems, boiler manufacturing, and heat exchangers. Among these materials, 1.4550 (AISI 347) and 1.4571 (AISI 316Ti) are two commonly selected grades. Although both are stabilized stainless steels, they differ significantly in high-temperature performance, corrosion resistance, mechanical properties, and application suitability.
What is 1.4550 stainless steel (AISI 347 / X6CrNiNb18-10)?
1.4550 is a niobium-stabilized austenitic stainless steel designed to resist intergranular corrosion during welding and prolonged exposure at temperatures between 450–850°C. It is suitable for heat exchangers, reformer tubes, pressure piping, exhaust components, and superheater tubes.
What is 1.4571 stainless steel (AISI 316Ti / X6CrNiMoTi17-12-2)?
1.4571 is a titanium-stabilized variant of 316 stainless steel, offering excellent corrosion resistance, especially in chloride, acidic, and marine environments. It is suitable for chemical equipment, heat exchangers in corrosive media, marine exhaust systems, and pressure vessels.
1.4550 vs 1.4571 stainless steel: High Temperature Resistance
| Grade | Max Continuous Service | Thermal Cycling Performance |
|---|---|---|
| 1.4550 (347) | 870–925°C | Excellent (Nb stabilization) |
| 1.4571 (316Ti) | 800–850°C | Good (Ti stabilization) |
1.4550 vs 1.4571 stainless steel: Chemical Composition (% by weight)
| Element | 1.4550 (347) | 1.4571 (316Ti) |
|---|---|---|
| Cr | 17.0–19.0 | 16.5–18.5 |
| Ni | 9.0–13.0 | 10.0–14.0 |
| Mo | – | 2.0–2.5 |
| C | ≤0.08 | ≤0.08 |
| Mn | ≤2.0 | ≤2.0 |
| Si | ≤0.75 | ≤0.75 |
| N | ≤0.10 | ≤0.10 |
| Stabilizer | Nb (0.8–1.0) | Ti (≥5 × C%) |
1.4550 vs 1.4571 stainless steel: Mechanical Properties
| Property | 1.4550 (347) | 1.4571 (316Ti) |
|---|---|---|
| Tensile Strength (Rm) | 520–720 MPa | 500–700 MPa |
| Yield Strength (Rp0.2) | ≥ 205 MPa | ≥ 210 MPa |
| Elongation | ≥40% | ≥40% |
| Hardness | ≤215 HB | ≤217 HB |
| Density | 7.90 g/cm³ | 8.00 g/cm³ |
Is the corrosion resistance of 1.4571 superior to that of 1.4550?
Yes. 1.4571 stainless steel (316Ti) has significantly better corrosion resistance than 1.4550 (347). The pitting resistance equivalent number (PREN) of 1.4571 is typically 23-25, while the PREN of 1.4550 is only 18-19, indicating its significantly weaker resistance to localized corrosion. In seawater, chemical processes, and environments containing chlorides, sulfuric acid, or brine, 1.4571 offers better long-term stability and a lower risk of pitting or crevice corrosion.
Is 1.4550 suitable for welded heat exchangers?
Yes, 1.4550 (AISI 347) is very suitable for welded heat exchangers, especially in high-temperature and corrosive environments. Because it contains tantalum/niobium elements, which prevent carbide precipitation (weld corrosion), it is a superior choice compared to standard grades such as 304/316.
What is the difference between 1.4404 and 1.4571?
1.4404 (316L) is a low-carbon molybdenum-bearing stainless steel great for general welding and corrosion resistance, while 1.4571 (316Ti) adds titanium for enhanced high-temperature stability and intergranular corrosion resistance, but its titanium particles can make it harder to polish and cold form, with 1.4404 generally being better for modern fabrication needing excellent finish and formability.
Gnee supplies both 1.4550 and 1.4571 stainless steel in a full range of forms, sizes, and surface finishes, offering fast delivery and reliable global export service. Our product line includes hot-rolled and cold-rolled plates (0.3–80 mm), coils and strips, seamless and welded pipes (Ø 6–630 mm), heat-exchanger tubing, bars (round, square, flat), and stainless steel fittings such as elbows, tees, reducers, and flanges.
We also provide customized processing including laser cutting, CNC machining, bending, and polishing. All materials come with EN 10204 3.1 / 3.2 certificates, 100% PMI testing, and third-party inspection by SGS, BV, or TUV to ensure strict dimensional and surface quality.
Packaging follows export-grade standards with seaworthy pallets and waterproof wrapping, and deliveries for stocked items are typically completed within 7–15 days, with custom sizes available for large projects. Gnee exports to more than 60 countries worldwide, supporting customers with stable quality and dependable service.
