Type 304 and 304L Stainless Steel

Learn About the Uses and Properties of These Two Metals

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Stainless steel takes its name from its ability to resist rusting thanks to the interaction between its alloying components and the environment to which they're exposed. Numerous types of stainless steel serve a variety of purposes and many overlaps. All stainless steels are comprised of at least 10 percent chromium. 

Type 304 Stainless Steel 

Type 304 is the most widely used austenitic stainless steel, and it's also known as "18-8" stainless steel because of its composition – it includes 18 percent chromium and 8 percent nickel.

Type 304 stainless steel has good forming and welding properties, as well as strong corrosion resistance and strength.

It also has good drawability. It can be formed into a variety of shapes and, in contrast to type 302 stainless, can be used without annealing. Common uses for type 304 stainless steel are found in the food industry. It's ideal for brewing, milk processing, and wine-making, as well as in pipelines, yeast pans, fermentation vats and storage tanks.​

Type 304 grade stainless steel is also found in sinks, tabletops, coffee pots, refrigerators, stoves and various utensils and other cooking appliances. It can withstand corrosion that can be caused by various chemicals found in fruits, meats, and milk. Other areas of use include architecture, chemical containers, heat exchangers, mining equipment, and marine nuts, bolts and screws. Type 304 is also used in mining and water filtration systems and in the dyeing industry.

 

Type 304L Stainless Steel 

Type 304L stainless steel is an extra-low carbon version of the 304 steel alloy. The lower carbon content in 304L minimizes deleterious carbide precipitation as a result of welding. 304L can, therefore, be used "as welded" in severe corrosion environments and it eliminates the need for annealing.

This grade has slightly lower mechanical properties than the standard 304 grade, but it's nonetheless widely used thanks to its versatility. Like Type 304 stainless steel, it's commonly used in beer-brewing and wine-making, but also for purposes beyond the food industry such as in chemical containers, mining, and construction. It's ideal for use in metal parts such as nuts and bolts that will be exposed to salt water. 

304 Stainless Physical Properties:

  • Density: 0.803g/cm3
  • Electrical resistivity: 72 microhm-cm (20C)
  • Specific Heat: 0.50 kJ/kg-K (0-100°C)
  • Thermal conductivity: 16.2 W/m-k (100°C)
  • Modulus of Elasticity (MPa): 193 x 103 in tension
  • Melting Range: 2550-2650°F (1399-1454°C)

Type 304 and 304L Stainless Steel Composition:

ElementType 304 (%)Type 304L (%)
Carbon0.08 max.0.03 max.
Manganese2.00 max.2.00 max.
Phosphorus0.045 max.0.045 max.
Sulfur0.03 max.0.03 max.
Silicon0.75 max.0.75 max.
Chromium18.00-20.0018.00-20.00
Nickel8.00-12.008.00-12.00
Nitrogen0.10 max.0.10 max.
IronBalanceBalance

Source: AK Steel Product Data Sheet. 304/304L Stainless Steel