SUS304 vs SS304 Stainless Steel: Which is Better?
Mar 28, 2025
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In many austenitic stainless steels, the difference between steel grades lies in which alloy components are added or removed. Therefore, SUS304 is called the parent of many other SUS materials.
SUS304 (Japanese JIS standard) is one of the most widely used versions of stainless steel. It consists of 18% Cr (chromium) and 8% Ni (nickel). It can still maintain its strength and heat resistance at high and low temperatures. It also has very good weldability, mechanical properties, cold workability and corrosion resistance at room temperature.
SS304 stainless steel has good weldability, heat resistance, corrosion resistance, low temperature strength, processability, mechanical properties, heat treatment does not harden, and has good thermal processability such as bending and stamping. SS304 is used in a wide range of applications in many industries, including food, medical and decorative work.
SUS304 vs SS304 Stainless Steel pipe
Corrosion resistance of 304 stainless steel
304 stainless steel performs well in various atmospheric environments and various corrosive media. However, in warm chloride environments, when the temperature exceeds 60 °C, it is prone to pitting, crevice corrosion and stress corrosion.
It is also considered resistant to drinking water up to about 200 mg/L chloride at ambient temperatures.
Chemical composition of SUS304 and SS304
|
304 Stainless Steel | |||
| Carbon (C) | ≤ 0.08 | ≤ 0.07 | ||
| Silicon (Si) | ≤ 1.00 | ≤ 0.75 | ||
| Manganese (Mn) | ≤ 2.00 | ≤ 2.00 | ||
| Phosphorus (P) | ≤ 0.045 | ≤ 0.045 | ||
| Sulfur (S) | ≤ 0.03 | ≤ 0.03 | ||
| Chromium (Cr) | 18.00 – 20.00 | 17.50 – 19.50 | ||
| Nickel (Ni) | 8.00 – 10.50 | 8.00 – 10.50 |
Physical Properties of SUS304 and SS304
| Property | Value |
|---|---|
| Density (g/cm³) | 7.8 – 8.2 |
| Melting Point (°C) | 1,230 – 1,480 |
| Specific Heat (J/kg·°C) | 440 – 500 |
| Electrical Resistivity (Ω·m) (20°C) | 7.3×10⁻⁷ – 8.5×10⁻⁷ |
| Thermal Expansion Coefficient (1/K) | 1.7×10⁻⁵ – 1.9×10⁻⁵ |
| Thermal Conductivity (W/m·K) | 14 – 20 |
Applications of SUS304 and SS304
Both stainless steels have a wide range of applications in almost all industries. Each variant can be roll-formed or baked into components for industrial applications such as processing equipment, machinery parts, automotive heads, as well as many household applications (including screws, food handling, food utensils, etc.).
SUS304 vs SS304 Grade Specification Comparison
| Grade | UN Number | Old British | European Standard | Swedish SS | Japanese JIS | Description |
|---|---|---|---|---|---|---|
| Bachelor | - | - | Name | - | - | - |
| 304 | S30400 | 304S31 | 58E | 1.4301 | X5CrNi18-10 | 2332 - Stainless Steel 304 |
| 304L | S30403 | 304S11 | - | 1.4306 | X2CrNi19-11 | 2352 - Stainless Steel 304L |
| 304H | S30409 | 304S51 | - | 1.4948 | X6CrNi18-11 | - |
The two materials are very close in physical and chemical properties, so it is easy to say that they are the same material.
Again, the main difference between the two is the standardization between the United States and Japan countries. This means that each material can be used interchangeably unless there are specific regulations or requirements imposed by the country or the customer.
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