304 STAINLESS STEEL ALLOY
Industries supplied include: Process equipment in mining, chemical, cryogenic, food, dairy, and pharmaceutical industries. 304 grade stainless has excellent welding and formability characteristics and is one of the most utilized stainless steels.
17.5 – 19.5
8.0 – 10.5
Physical Properties At 70°F (At 20°C)
0.29 lb./in3 / (8.03 g/cm3)
Modulus of Elasticity (E)
28.0 x 103 ksi / (193 x 103MPa)
Coefficient of Expansion
9.4 x 10-6 microinches/in.-°F (70-600°F) / (16.9 μm/m-°C) (20-300°C)
28.4 μ ohm.in / (72 μ ohm.cm)
9.4 Btu-in./ft.2hr.-°F / (16.2 W/m-K)
AMS 5512, ASTM A313, ASTM A240, ASTM A580, ASTM A666
Typical Mechanical Properties
Tensile Strength Min (UTS)
75 ksi (515 MPa)
0.2% YS Min
30 ksi (205 MPa)
Elongation% in 2” Min (50.8 mm)
92 HRBW (Max)
*Tempered Properties available upon request*
Additional Information on 304 Stainless Steel
Grade 304 stainless steel is the most widely used of the stainless steels. It combines great corrosion resistance with working flexibility. It offers excellent cost benefits and a clean, bright finish.
How 304 Stainless Steel Protects against Rust
To understand what makes 304 stainless steel so resistant to corrosion, you need to look at its physical composition. Most iron-based metals react with water to produce the reddish iron oxide known better as rust. The oxygen atoms in the water pulls iron off of the base metal to form the porous rust structure with no real strength. As the rust particles crumble away in chunks, new iron bearing metal is exposed and the process repeats. Before long, your iron-based product is a husk.
The major ingredient in 304 stainless steel is chromium. A hard, brittle metal, chromium has some remarkable properties, but an inability to react with water is not one of them. If chromium gets wet, as with iron, it oxidizes.
The chromium oxide formed in steel discolors it too. This is why no stainless steel can in truth be called ‘stainless.’ The difference is in the thickness of the chromium oxide layer, only a few molecules thick and extremely dense. This layer is said to be passivated and is so tough it prevents the further diffusion of oxygen molecules into the steel beneath. With iron, in comparison, oxygen molecules continue to spread, eating further into the metal beneath.
Not only does chromium oxide provide a tough protective barrier, but it is also self-renewing. The higher the chromium content in the steel, the faster the protective barrier renews itself. Once oxidized, 304 stainless steel rusts less than two-thousandths of an inch a year.