SS204 and SS304 are both austenitic stainless steels, but they belong to different series and serve distinct purposes. SS304, a 300-series alloy, is the most widely used stainless steel for its excellent corrosion resistance and versatility. SS204, from the 200-series, is a cost-effective alternative with higher manganese and lower nickel, making it suitable for less demanding environments.
Chemical Composition Comparison
|
Element |
SS204 (%) |
SS304 (%) |
Impact |
|---|---|---|---|
|
Chromium (Cr) |
16-18 |
18-20 |
Similar base for corrosion, but SS304 has slightly more for enhanced protection. |
|
Nickel (Ni) |
1-3 |
8-10.5 |
SS304's higher Ni improves ductility and resistance; SS204's low Ni makes it cheaper but less corrosion-resistant. |
|
Manganese (Mn) |
5-7 |
≤2 |
Higher in SS204 for austenite stability, increasing hardness but reducing corrosion performance. |
|
Carbon (C) |
≤0.15 |
≤0.08 |
Higher in SS204, potentially leading to more sensitization. |
|
Silicon (Si) |
≤1 |
≤0.75 |
Minor difference; both aid oxidation resistance. |
Mechanical Properties Comparison
|
Property |
SS204 |
SS304 |
Notes |
|---|---|---|---|
|
Tensile Strength |
620 MPa |
515 MPa (min) |
SS204 is stronger in annealed state but less formable. |
|
Yield Strength |
310 MPa |
205 MPa (min) |
SS204 has higher yield but can be brittle. |
|
Elongation |
40% |
40% |
Similar ductility. |
|
Hardness (Brinell) |
201 (max) |
201 (max) |
SS204 often feels harder in practice. |
|
Density |
7.8 g/cm³ |
7.93 g/cm³ |
Comparable. |
Corrosion Resistance: SS204 vs SS304
SS304 significantly outperforms SS204 in corrosion resistance due to higher nickel, making it suitable for outdoor or humid environments. SS204 rusts more easily and is best for indoor use. In salt spray tests, SS304 lasts longer, while SS204 is prone to red rust. Gangsteel's SS304 is ideal for marine applications, unlike SS204.
Weldability and Formability
Both are weldable, but SS304 is better for complex welds due to lower manganese, which can cause cracking in SS204. Formability is similar, but SS304 is more ductile.
Applications of SS204 and SS304
SS304 for corrosive or outdoor use (e.g., chemical tanks, marine fittings); SS204 for indoor, non-corrosive (e.g., furniture, utensils).
