SUS321 Stainless Steel :Chemical Composition, Properties and Applications
SUS321 Stainless Steel: Chemical Composition, Properties and Applications
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What is SUS321 Stainless Steel?
SUS321 stainless steel is a titanium-stabilized austenitic stainless steel widely used in high-temperature applications where resistance to intergranular corrosion is essential. Compared with SUS304, SUS321 contains 0.3–0.7% Titanium (Ti), which effectively prevents chromium carbide precipitation at 450–850°C. This makes the grade suitable for heat exchangers, exhaust systems, furnace parts, and pressure vessels operating under elevated temperatures.
Is 321 stainless better than 304?
321 Stainless has similar corrosion resistance, formability, and strength as 304 Stainless, but it is more resistant to high-temperature oxidation and creep. It has a maximum operating temperature of around 1580°F and a maximum strength of around 95 ksi.
What is 321 stainless steel used for?
SUSU321 stainless steel is used in applications requiring high-temperature resistance and excellent intergranular corrosion resistance, such as aerospace components like exhaust manifolds and aircraft parts. Other common uses include furnace parts, heating element tubing, heat exchangers, and equipment for chemical, petrochemical, and food processing industries.
Equivalent Grades of 321 Stainless Steel
| Country/Region | Standard/Specification | Equivalent Grade |
| China | GB/T 20878, GB 4234 | 0Cr18Ni10Ti, 1Cr18Ni11Ti, H0Cr20Ni10Ti |
| USA | ASTM A240, ASME SA240 | 321 |
| EU | EN 10088-2 | X6CrNiTi18-10 (1.4541) |
| Germany | DIN 17440, DIN EN 10088-2 | X10CrNiTi18-9, X6CrNiTi18-10 |
| GOST 5632 | 08KH18N10T, 08KH18N12T, 12KH18N10T | |
| Japan | JIS G4304, JIS G4303 | SUS321 |
| England | BS 1449, BS EN 10088-2 | 321S31 |
SUS321 stainless steel Chemical Composition
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤0.08 |
| Chromium (Cr) | 17.0 – 19.0 |
| Nickel (Ni) | 9.0 – 12.0 |
| Titanium (Ti) | ≥5 × C and ≤0.7 |
| Manganese (Mn) | ≤2.0 |
| Silicon (Si) | ≤1.0 |
| Phosphorus (P) | ≤0.045 |
| Sulfur (S) | ≤0.03 |
Mechanical Properties of SUS321
| Property | Typical Value |
|---|---|
| Tensile Strength | ≥515 MPa |
| Yield Strength | ≥205 MPa |
| Elongation | ≥40% |
| Hardness (HRB) | ≤95 |
| Density | 7.93 g/cm³ |
| Working Temperature | Up to 870°C (continuous) |
Advantages of SUS 321 Stainless Steel:
1. Excellent Resistance to Intergranular Corrosion
The titanium content of 321 stainless steel effectively binds carbon, preventing carbide precipitation and protecting the weld-affected zone, making it ideal for pressure vessels and pipelines.
2. High-Temperature Stability
It can operate reliably in the range of 600–870°C, preventing scaling and maintaining mechanical strength.
3. Good Weldability and Machinability
Conventional welding methods can be used, avoiding the intergranular corrosion risks common in 304 stainless steel.
4. Superior Creep Strength and Stress Fracture Strength
Compared to 304/304L stainless steel, SUS321 stainless steel exhibits higher strength under long-term high-temperature service conditions.
Comparison: SUS321 vs SUS304 vs SUS316
| Grade | Main Difference | Best For |
|---|---|---|
| SUS321 | Ti-stabilized, best for high-temperature stability & anti-sensitization | Exhaust systems, heat exchangers, heaters |
| SUS304 | Standard corrosion resistance, cost-effective | General equipment, kitchenware |
| SUS316 | Mo-added, strong chloride resistance | Marine, chemical processing |
What is the temperature limit of SUS321?
The temperature limit for SUS321 is a maximum continuous service temperature of 870°C (1600°F) in air, but it can be used up to 900°C (1650°C) for intermittent service, with higher limits for steam. The addition of titanium provides excellent oxidation resistance and prevents intergranular corrosion in the 425-816°C (800-1500°F) range.
GNEE currently has SUS 321 (UNS S32100) products in stock, including: sheets, plates, coils, strips, tubes, bars, and wires. In addition, we offer a variety of surface treatments for your selection, such as: No. 1, 2B, 2D, BA, No. 3, No. 4, HL, No. 8, sandblasting, etc.
We guarantee 100% quality. We will never deliver any defective products to our customers. Please contact us to customize your product specifications, including shape, condition, surface treatment, and processing technology.
