Why Choose SUS321 Stainless Steel for Heat-Resistant Applications
Aug 15, 2025
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What is SUS321 Stainless Steel?
SUS321 stainless steel is a Ni-Cr-Ti austenitic stainless steel stabilized with titanium. It offers excellent corrosion resistance, high-temperature strength, and creep resistance. It is suitable for high-temperature welded components, such as boiler heat exchangers and chemical equipment, providing corrosion protection in elevated-temperature environments and ensuring long-term stable operation. SUS321 serves as a reliable material choice for engineering applications under high-temperature conditions.
Why Choose SUS321 Stainless Steel for Heat-Resistant Applications?
1.Titanium Stabilization Prevents Sensitization
Chromium carbide can precipitate between 425–850°C, causing sensitization-a key weakness of 304/316 stainless steels. SUS321 effectively suppresses intergranular corrosion by forming titanium carbide (TiC) structures. It maintains excellent intergranular corrosion resistance within the 427–816°C range, whereas 316L stainless steel is prone to sensitization at high temperatures.
2.Excellent High-Temperature Strength
For continuous service, SUS321 can withstand temperatures up to 900°C (intermittent service up to 925°C) without scaling or embrittlement. Even at 600°C, it retains high mechanical performance, with tensile strength approximately 520–700 MPa and yield strength around 205–310 MPa.
3.Industry Applications
Petrochemical Industry: Cracking furnace tubes, flare stacks (sulfur-resistant).
Aerospace Industry: Jet engine components, afterburner liners.
Power Plants: Boiler tubes, superheater components.
Enhanced Mechanical Properties
| Property | SUS321 Stainless Steel |
|---|---|
| Tensile Strength | 515–730 MPa |
| Yield Strength | ≥ 205 MPa |
| Elongation | ≥ 40% |
| Hardness | ≤ 217 HB |
Processing and Maintenance
Heat Treatment: SUS321 requires solution annealing at 920–1150°C and stabilization treatment at 850–930°C to ensure uniform carbide distribution and further enhance heat resistance.
Welding Process
Welding requires controlling the current (120–150 A) and welding speed (15–20 cm/min). Titanium stabilization can reduce carbide precipitation in the weld by approximately 75%, improving corrosion resistance.
Can SUS321 withstand thermal cycling?
Yes, SUS321 maintains mechanical integrity and resists scaling even under repeated heating and cooling cycles.
For any heat-resistant application, SUS321 stainless steel provides superior performance over standard austenitic grades like SUS304. Its titanium stabilization, high-temperature strength, and oxidation resistance make it a preferred choice for industries requiring durable, long-lasting, and reliable materials.
Contact us today to source SUS321 pipes, tubes, sheets, and plates tailored to your high-temperature industrial applications.Email: sales@gneestainless.com
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