SUS321 vs SUS304 Stainless Steel: Key Differences for Buyers
SUS321 vs SUS304 Stainless Steel: Key Differences for Buyers
SS 321 Chemical Composition.pdf
The main difference is that SUS321 contains titanium, which can prevent intergranular corrosion, while SUS304 is a general-purpose steel that lacks this stability and is prone to corrosion after welding or exposure to high temperatures (above 800°C or 1472°F).
What is SUS 321 material equivalent to?
SUS 321 is equivalent to several other material designations, including AISI 321, UNS S32100, and 1.4541 (European/DIN standard). It is a titanium-stabilized austenitic stainless steel similar to grade 304, but with the addition of titanium to prevent carbide precipitation at high temperatures, making it more resistant to intergranular corrosion after welding.
What is sus 304 material?
SUS 304 is a standard grade of stainless steel, where "SUS" stands for the Japanese Industrial Standard and "304" is the specific grade. This is an austenitic stainless steel, also known as 18/8 stainless steel, due to its composition of approximately 18% chromium and 8% nickel. It is highly valued for its excellent corrosion resistance, durability, and ease of formability, making it widely used in kitchenware, medical equipment, and structural applications.
What is the difference between SUS304 and sus321?
The main difference is that SUS321 is a titanium-stabilized version of SUS304, making it more resistant to intergranular corrosion when exposed to high temperatures, especially after welding. While SUS304 has excellent all-around corrosion resistance, the addition of titanium in SUS321 prevents the formation of chromium carbides in the 425-850°C range, which is a major limitation of 304 in high-heat applications. This makes SUS321 more suitable for applications involving high-temperature exposure, such as those in the aerospace and chemical processing industries.
What is the equivalent cast grade of 321 stainless steel?
The equivalent cast grades of 321 stainless steel are not entirely the same. However, the cast austenitic stainless steel grade ACI-ASTM CE30 is considered a comparable material.
SUS321 vs SUS304 Stainless Steel: Chemical Composition
| Element | SUS304 (%) | SUS321 (%) |
|---|---|---|
| Carbon (C) | ≤0.08 | ≤0.08 |
| Chromium (Cr) | 18.0–20.0 | 17.0–19.0 |
| Nickel (Ni) | 8.0–10.5 | 9.0–12.0 |
| Titanium (Ti) | - | 5 × C min. (≤0.7) |
| Manganese (Mn) | ≤2.0 | ≤2.0 |
| Silicon (Si) | ≤1.0 | ≤1.0 |
| Phosphorus (P) | ≤0.045 | ≤0.045 |
| Sulfur (S) | ≤0.03 | ≤0.03 |
SUS321 vs SUS304 Stainless Steel: Mechanical Properties
| Property | SUS304 | SUS321 |
|---|---|---|
| Tensile Strength | ≥520 MPa | ≥515 MPa |
| Yield Strength | ≥205 MPa | ≥205 MPa |
| Elongation | ≥40% | ≥40% |
| Hardness (HRB) | ≤92 | ≤95 |
| Working Temperature | ≤800°C (short-term) | Up to 870°C (continuous) |
High Temperature Resistance
If your application involves temperatures that can lead to chromium carbide precipitation, especially in the range of 800°F to 1500°F (427°C to 816°C), the added titanium in SUS321 helps prevent this corrosion.
Weldability
SUS321 is specifically designed to withstand the high temperatures of welding without the intergranular corrosion that occurs after welding, unlike SUS304. Specific Automotive Components: For high-temperature components such as turbocharger manifolds or exhaust systems where operating temperatures may exceed 1472°F (800°C), SUS321 is a better choice.
SS 321 vs SS 304 Price
In today's stainless steel market, SS321 typically costs 8–15% higher than SS304 due to its Titanium-stabilized composition and enhanced high-temperature resistance. For reference, SS304 sheet usually ranges from USD 2.2–2.6 per kg, while SS321 sheet is generally USD 2.5–3.0 per kg, depending on thickness, surface finish, and order quantity.
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.
