SUS304 Stainless Steel

SUS304 is a widely used austenitic stainless steel with 18-20% Cr and 8-10.5% Ni, known as "food-grade stainless steel". It has excellent corrosion resistance, ductility, and weldability, serving as the benchmark for general-purpose stainless steel. Its non-magnetic property and stable performance make it suitable for diverse industries from household to industrial.

Chemical Composition (wt%): C ≤0.08, Si ≤1.00, Mn ≤2.00, P ≤0.045, S ≤0.030, Cr=18.00-20.00, Ni=8.00-10.50, Fe=Balance

Mechanical Properties: Tensile Strength ≥515MPa, Yield Strength ≥205MPa, Elongation ≥40%, Hardness (HB) ≤201

Performance Advantages: Strong corrosion resistance in mild acids/bases; excellent formability for complex shapes; good weldability without post-treatment; non-magnetic and aesthetic.

Equivalent Grades: ASTM A240 304, EN 1.4301, UNS S30400

Applications: Food processing equipment, kitchenware, medical instruments, architectural decoration, chemical storage tanks.

FAQ

1. Q: Why is SUS304 called food-grade stainless steel? A: SUS304 meets food contact safety standards because its 18% Cr and 8% Ni form a dense oxide film, preventing metal ion leaching into food. It resists corrosion from organic acids in fruits, dairy, and sauces, avoiding contamination. Its smooth surface is easy to clean, meeting hygiene requirements. Unlike carbon steel, it doesn't rust or taint food flavor, making it the first choice for food machinery and tableware.

2. Q: Will SUS304 rust? A: It's rust-resistant but not rust-proof. In dry or clean environments, it stays intact. However, in high-chloride areas (coastal salt spray) or long-term contact with acidic solutions (vinegar, pickle), the oxide film may break, causing pitting. Scratches can also reduce corrosion resistance. Regular cleaning with neutral detergent and drying can prevent rust, ensuring its service life.

3. Q: How does SUS304 perform in high-temperature environments? A: It works well at -196°C to 870°C. At low temps, it retains ductility without brittleness; at high temps, it resists oxidation. But above 870°C, its strength decreases, unsuitable for long-term high-heat parts like furnace cores. It's ideal for medium-temp applications like steam pipelines or food sterilization equipment, balancing cost and performance.

4. Q: Is SUS304 magnetic? A: Normally non-magnetic, but cold working (stamping, rolling) can induce weak magnetism due to austenite-to-martensite transformation. This magnetism is temporary-annealing at 1050°C and rapid cooling restores non-magnetic property. The weak magnetism doesn't affect its corrosion resistance or use, so it's still suitable for non-magnetic required scenarios like medical devices.

5. Q: How to distinguish genuine SUS304 from fake ones? A: Use three methods. First, check the material stamp (e.g., "304" on tableware). Second, use a nickel detector-genuine has ≥8% Ni. Third, conduct a copper sulfate test: clean the surface, apply copper sulfate solution; genuine won't turn red, fake (e.g., 201) will due to low Ni.