Type 316 and 316L Stainless Steel

Compare Two Types of Stainless Steel

Aircraft construction
Maximilian Stock Ltd./Photographer's Choice/Getty Images

Alloys are often added to steel to increase desired properties. Marine grade stainless steel, called type 316, is resistant to certain types of interactions. There are a variety of different types of 316 stainless steel, including 316 L, F, N, H, and several others. Each is slightly different, and each is used for different purposes.

Qualities Shared By Type 316 and 316L Steel

While similar to Type 304 both Type 316 and 316L exhibit better corrosion resistance and are stronger at elevated temperatures.

They are also both non-hardenable by heat treatment and can be readily formed and drawn.

Annealing 316 and 316L stainless steels require heating to between 1900-2100°F (1038-1149°C) before rapidly quenching.

How Type 316 and 316L Steel Are Different From One Another

316 stainless steel has more carbon in it than 316L. This is easy to remember, as the L stands for "low." But even though it has less carbon, 316L is very similar to 316 in almost every way. Cost is very similar, and both are durable, corrosion resistant, and a good choice for high-stress situations.

316L, however, is a better choice for a project that requires a lot of welding. That's because 316 is more liable than 316L to weld decay (though 316 can be annealed to resist weld decay). 316L is also a great stainless steel for high temperature, high corrosion uses, which is why it's so popular for use in construction and marine projects.

Neither 316 nor 316L are the cheapest option (304 and 304L are similar but lower-priced). And neither are the most durable option (317 and 317L, because of their higher molybdenum content, are better for overall corrosion resistance). 

What Are the Qualities of Type 316 Steel?

Type 316 steel is an austenitic chromium-nickel stainless steel that contains between two and three percent molybdenum.

The molybdenum content increases corrosion resistance, improves resistance to pitting in chloride ion solutions and increases strength at high temperatures.

Type 316 grade stainless steel is particularly effective in acidic environments. This grade of steel is effective in protecting against corrosion caused by sulfuric, hydrochloric, acetic, formic and tartaric acids, as well as acid sulfates and alkaline chlorides.

How Is Type 316 Steel Used?

Common uses for type 316 stainless steel include in the construction of exhaust manifolds, furnace parts, heat exchangers, jet engine parts, pharmaceutical and photographic equipment, valve and pump parts, chemical processing equipment, tanks, evaporators, as well as pulp, paper and textile processing equipment and any parts exposed to marine environments.

What Are the Qualities of Type 316L Steel?

Type 316L stainless steel is an extra-low carbon version of the 316 steel alloy. The lower carbon content in 316L minimizes deleterious carbide precipitation as a result of welding. Consequently, 316L is used when welding is required in order to ensure maximum corrosion resistance.

Physical Properties of Type 316 Steels

  • Density: 0.799g/cm3
  • Electrical resistivity: 74 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: 2500-2550°F (1371-1399°C)

Type 316 and 316L Stainless Steel Composition:

The following is a breakdown of the percentages of various elements used to create316 and 316L stainless steel:

ElementType 316 (%)Type 316L (%)
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.
Chromium16.00-18.0016.00-18.00
Nickel10.00-14.0010.00-14.00
Molybdenum2.00-3.002.00-3.00
Nitrogen0.10 max.0.10 max.
IronBalanceBalance

Source: AK Steel Product Data Sheet. 316/316L Stainless Steel