316/316L Stainless Steel
GENERAL PROPERTIES
Type 316L is an extra-low carbon variation of Type 316 that eliminates harmful carbide precipitation due to welding.
Type 316L (UNS S31603) is the low carbon version of Type 316 and is immune from sensitization (grain boundary carbide precipitation). Thus it is extensively used in heavy gauge welded components (over about 6mm).
As one of the most commonly used austenitic stainless steels, Type 316 eliminates most of the roughness that characterized then earlier grades of stainless steel with the same nominal composition. Type 316L (UNS S31603), is an extra low carbon variation of Type 316 that eliminates harmful carbide precipitation due to welding.
APPLICATIONS
Type 316L is used extensively for welded equipment that cannot be annealed and for applications where maximum corrosion resistance is required in more corrosive environments. It is also used in refrigeration as well as environmental applications.
The major uses of grade 316L stainless steel include:
- Pharmaceutical equipment
- Chemical equipment
- Heat exchangers
- Heat exchangers
- Tanks and vessels
- Boilers and pressure vessels
- Food processing equipment
- Interior and exterior components of machinery
- Ball valves and flanges
- Autoclaves
- Surgical instruments
- Piping systems
TYPICAL CHEMICAL COMPOSITION
The typical chemical composition of Type 316L stainless steel is shown in the following table.
Element % by Weight
Carbon 0.03
Manganese 2.00
Phosphorus 0.045
Sulfur 0.030
Silicon 0.75
Chromium 16.00 – 18.00
Nickel 10.00 – 14.00
Molybdenum 2.00 – 3.00
Nitrogen 0.10
Iron Balance
TYPICAL MECHANICAL PROPERTIES
The typical mechanical properties of Type 316L stainless steel are:
Tensile Strength 70,000 to 90,000 psi
Yield Strength 25,000 to 70,000 psi
Elongation in 2” 30% minimum
Hardness Rockwell B 55 – 95
Impact Resistance 360 ft/lbs
CONCLUSION
Type 316L stainless steel is much more resistant to corrosive attack than the 316 and maintains its strength, toughness, and ductility even in all types of applications where heavy gauge welding is required. Its combination of strength and ease of fabrication make it one of the most popular grades of stainless steel for a wide variety of industrial applications. Its superior weldability and good thermal properties also make Type 316L suitable for hostile environments. Its wide application range also shows its versatility as a material.
