SCS13 vs SUS304 Stainless Steel: What is the Difference?
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When sourcing stainless steel components for valves, pumps, and pressure systems, buyers often encounter two commonly used designations: SCS13 and SUS304. While both refer to 304-grade stainless steels, understanding their differences in form, standards, and applications is essential for making the right material choice in industrial projects.
What are the SCS13 and SUS304 Stainless Steel Standards?
| Item | SCS13 | SUS304 |
|---|---|---|
| Standard Source | Japanese JIS G5121 (Casting Stainless Steel Standard) | Japanese JIS G4303 (Wrought Stainless Steel Standard) |
| Material Type | Cast stainless steel (formed by casting process) | Wrought stainless steel (formed by rolling/forging process) |
| International Equivalent Grade | ASTM CF8 (UNS J92600) | ASTM 304 (UNS S30400) |
What Is SUS304 Stainless Steel?
SUS304 is an austenitic stainless steel defined under the Japanese JIS G4303 standard. It contains approximately 18% chromium and 8% nickel, offering excellent corrosion resistance, good formability, and weldability.
Typical forms: Cold-rolled/hot-rolled sheet, plate, bar, tube
Surface finishes: 2B, BA, HL, No.4, etc.
Applications: Architectural panels, food-grade piping, kitchen equipment, tanks, and structural components
Standards: JIS G4303 / G4304 / G4305
Organizational characteristics: The grains are fine, and the strength can be improved through cold deformation after processing (such as hardening treatment).
What Is SCS13 Stainless Steel?
SCS13 is the Japanese casting equivalent of SUS304, specified under JIS G5121. It is a cast stainless steel commonly used in the manufacture of valve bodies, pump housings, flanges, and other pressure-bearing cast components.
Equivalent to: ASTM A351 CF8
Process: Sand casting, investment casting
Applications: Pressure valves, marine components, pump casings, chemical processing
Standards: JIS G5121
Organizational characteristics: The grains are coarse and the organization uniformity is poor, so the performance needs to be improved through solution treatment (1050-1100℃ water cooling).
SCS13 vs SUS304 chemical composition
| Element | SCS13 (JIS G5121, Cast) | SUS304 (JIS G4303, Wrought) |
|---|---|---|
| Carbon (C) | ≤ 0.08% | ≤ 0.08% |
| Silicon (Si) | ≤ 1.00% | ≤ 1.00% |
| Manganese (Mn) | ≤ 1.50% | ≤ 2.00% |
| Phosphorus (P) | ≤ 0.04% | ≤ 0.045% |
| Sulfur (S) | ≤ 0.03% | ≤ 0.03% |
| Chromium (Cr) | 18.0 – 21.0% | 18.0 – 20.0% |
| Nickel (Ni) | 8.0 – 11.0% | 8.0 – 10.5% |
SCS13 Vs SUS304 Stainless Steel Corrosion Resistance
During the casting process of SCS13 stainless steel, local component segregation or carbide precipitation may lead to slightly higher sensitivity to intergranular corrosion. Strict solution treatment is required to eliminate the risk. The pitting resistance in chloride ion environments (such as seawater) is slightly weaker than that of SUS304.
SUS304 stainless steel forgings have uniform structure, high surface finish, and stronger resistance to local corrosion (pitting, crevice corrosion), especially suitable for scenes that require polishing or passivation treatment (such as food equipment).
Mechanical Properties : SCS13 vs SUS304
| Property | SCS13 (Cast) | SUS304 (Wrought) |
|---|---|---|
| Tensile Strength (MPa) | ≥ 485 MPa | ≥ 520 MPa |
| Yield Strength (0.2%, MPa) | ≥ 177 MPa | ≥ 205 MPa |
| Elongation (%) | ≥ 25% | ≥ 40% |
| Hardness (HB) | ≤ 187 HB | ≤ 90 HRB (≈183 HB) |
| Density | ~7.93 g/cm³ | ~7.93 g/cm³ |
| Modulus of Elasticity | ~193 GPa | ~193 GPa |
Machinability and heat treatment
SCS13:
Casting process: The pouring temperature and cooling rate need to be controlled to avoid shrinkage holes; solid solution treatment is required after welding to restore corrosion resistance. ER308L welding rod is recommended.
SUS304:
Machinability: It can be formed by cold rolling, stamping, welding (conventional 308 welding rod) and other processes. Cold processing can improve strength (such as hardening treatment).
Heat treatment: Annealing (stress relief) or solid solution treatment (restore corrosion resistance). The process is mature and the cost is low.
SUS304 Stainless Steel Product Forms Offered by Gnee
As a professional stainless steel supplier, Gnee maintains a long-term inventory of various SUS304 stainless steel product forms to meet the diverse processing and application needs of customers across multiple industries:
| Product Form | Size Range | Key Features & Applications |
|---|---|---|
| Stainless Steel Sheet / Plate | Thickness: 0.3mm–100mm, Width: up to 2000mm | Available in 2B, BA, No.4, HL finishes; used for decoration, equipment enclosures, etc. |
| Stainless Steel Pipe / Tube | Outer Diameter: 6–219mm, Wall Thickness: 0.5–6mm | TP304 welded or seamless tubes; ideal for fluid transport and structural applications |
| Stainless Steel Round Bar | Diameter: 3–300mm | Hot-rolled or cold-drawn; suitable for machining, structural parts, fasteners |
| Stainless Steel Coil | Thickness: 0.3mm–6mm, Width: ≤1500mm | For laser cutting, stamping, forming, and welding processes |
All products comply with JIS G4303 / ASTM / EN standards, and support third-party inspections (SGS, BV, TÜV) as well as export-grade packaging.
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