304 stainless steel is a dominant austenitic stainless steel grade, renowned for its balanced performance and versatility. Below is a structured overview of its key parameters, product-specific standards, and typical applications.
1. Core Chemical & Mechanical Parameters
Its properties are defined by strict compositional and performance criteria, ensuring consistency across uses:
| Parameter Category | Key 指标 (Key Indicators) |
|---|---|
| Chemical Composition | - Chromium (Cr): 18.0% – 20.0% (forms a protective oxide layer for corrosion resistance) - Nickel (Ni): 8.0% – 10.5% (stabilizes the austenitic structure) - Carbon (C): ≤ 0.08% (reduces carbide precipitation and intergranular corrosion risk) - Manganese (Mn): ≤ 2.0% - Silicon (Si): ≤ 1.0% - Phosphorus (P): ≤ 0.045% - Sulfur (S): ≤ 0.030% |
| Mechanical Properties | - Tensile Strength: ≥ 515 MPa - Yield Strength (0.2% offset): ≥ 205 MPa - Elongation (in 50mm): ≥ 40% - Hardness (Brinell): ≤ 201 HB; (Rockwell B): ≤ 92 HRB |
| Other Key Traits | - Density: ~7.93 g/cm³ - Melting Point: 1400–1450°C - Magnetic Behavior: Non-magnetic (in annealed state) |
2. Standards for Different 304 Products
Global standards regulate 304 stainless steel based on its form (e.g., sheets, pipes, wires) to ensure quality for specific industries. Common standards include:
| Product Form | Major Global Standards | Key Focus |
|---|---|---|
| Plates/Sheets/Coils | - ASTM A240 (U.S.) - EN 10088-2 (EU) - JIS G4305 (Japan) - GB/T 3280 (China) |
Thickness tolerance, surface finish (e.g., 2B, BA), corrosion resistance testing |
| Pipes/Tubes | - ASTM A312 (seamless/welded, for pressure systems) - EN 10216-5 (seamless) - JIS G3459 |
Pressure resistance, weld quality, dimensional accuracy |
| Bars/Wires | - ASTM A276 (bars/rods) - EN 10088-3 (bars) - JIS G4303 (bars) |
Tensile strength, straightness, surface smoothness |
| Food-Contact Parts | - FDA 21 CFR §177.2600 (U.S.) - EU Regulation (EC) No. 1935/2004 |
Non-toxicity, no migration of harmful elements (e.g., nickel) into food |
3. Typical Applications
304 stainless steel’s corrosion resistance, ductility, and food safety compliance make it suitable for diverse sectors:
- Food & Beverage Industry: Kitchen utensils (pans, knives), food processing equipment (mixers, conveyors), storage tanks, and dairy machinery (complies with FDA/EU food safety standards).
- Architecture & Construction: Building facades, handrails, elevator panels, roofing, and decorative parts (resists urban air pollution and rain corrosion).
- Household & Daily Use: Sinks, dishwashers, refrigerators, and water bottles (easy to clean and rust-proof).
- Industrial & Medical: Chemical storage tanks (for mild chemicals), heat exchangers, and non-critical medical tools (e.g., instrument trays—note: high-sterility parts use 316L instead).
It is not recommended for extreme conditions (e.g., strong acids like hydrochloric acid, or high-temperature industrial furnaces above 800°C), where grades like 316 or 309L are preferred.
