What Is AISI 316 Material

Abstract

Stainless Steel 316 is a stainless steel containing Chromium-Nickel-Molybdenum. Grade 316 Stainless Steel is the second most commonly used stainless steel, behind 304 stainless steel. It is an austenitic, corrosion-resistant steel with excellent strength, toughness, fabrication characteristics and weldability. These two are chemically similar, containing comparable levels of nickel (Ni) and chromium (Cr). Nickel enhances the low-temperature performance of stainless alloys, generally imparting good ductility to avoid brittleness in cryogenic conditions. Chromium, meanwhile, is the main element responsible for the corrosion-resistant properties of stainless steels.

316 is a member of the 18/8 chromium nickel family of austenitic stainless steels, with an addition of 2% molybdenum for improved corrosion resistance, particularly to localised corrosion in chloride containing environments. The very tough and ductile austenitic structure gives grade 316 excellent formability and fabrication characteristics.

Physical Properties and Datasheet

AISI 316 Approximate Average Composition Range

Physical Properties of AISI 316

Mechanical Properties of AISI 316

Characteristics of stainless steel 316

Toughness/Hardness

Austenitic stainless steels are inherently tough and 316 stainless steel is no different, maintaining the ductile fracture mode and high absorbed energy in impact tests to cryogenic temperatures (-200°C).

Pressure Vessels

AS1210, Pressure Vessels, allows the use of grade 316 up to a temperature of 800°C. The standard allows the use of higher design stresses for 316H at all temperatures.

Cold Fabrication

Grade 316 is readily workable, by the standard methods of sheet metal working, with the exception that it cannot be oxygen cut. Plasma cutting is normal. The deep drawing capability of grade 316 is outstanding, because of its high austenite stability.

High Temperature Corrosion

The generally accepted maximum service temperatures for grade 316 (and grade 304) in air are 870°C for intermittent service and 925°C for continuous service.

Corrosion Resistance

When exposed to a variety of hostile conditions and media, stainless steel 316 possesses good corrosion resistance. Although it is often referred to as "marine grade," it is not resistant to warm sea water. Pitting and crevice corrosion may occur in warm chloride conditions. Above 60°C, Grade 316 is susceptible to stress corrosion cracking.

Heat Resistance

In intermittent service to 870°C and continuous service to 925°C, stainless steel 316 offers strong oxidation resistance. If corrosion resistance in water is necessary, however, prolonged usage at 425-860°C is not suggested. Because of its resistance to carbide precipitation, 316L is preferred in this case. Grade 316H is indicated when strong strength is needed at temperatures over 500°C.

Machinability

The machinability of stainless steel 316 is exceptional. The following guidelines may help you improve your machining: The cutting edges must remain razor-sharp. Excessive work hardening is caused by dull edges. Light cuts should be made, but they should be deep enough to avoid work hardening by riding on the material's surface. Chip breakers should be used to help keep swarf out of the way of the job. Heat concentrates at the cutting edges due to austenitic metals' low thermal conductivity. Coolants and lubricants are thus required and must be used in huge amounts.

Welding

Excellent weldability by all standard fusion methods, both with and without filler metals. AS 1554.6 pre-qualifies welding of 316 with Grade 316 and 316L with Grade 316L rods or electrodes (or their high silicon equivalents). Heavy welded sections in Grade 316 require post-weld annealing for maximum corrosion resistance. This is not required for 316L. Grade 316Ti may also be used as an alternative to 316 for heavy section welding.

Application of stainless steel 316

Benches and equipment for the laboratories: Being very easy to clean and multipurpose, this alloy is very suitable for the laboratory equipment and benches.

Household Equipment: stainless steel 316 is suitable for making household utensils such as knives and cutleries. They are suitable based on their mechanical properties, durability, heat resistance, and aesthetic appeal.

Food and Beverage industry: The intrinsic property of stainless steel 316  to be resistant to corrosion makes its way to the food and beverage industry. From storage to transportation and from easy cleaning to sterilisation, this type is very beneficial to the industry.

Aerospace Industry: Stainless steel 316 is a material of huge favor in making parts used in the aerospace industry, for example, it can be used to manufacture CNC machining aerospace parts. This comes as a result of its lightweight, tensile strength, corrosion resistance, and extreme durability. SS 316 is suitable for making aerospace parts such as actuators, fasteners, landing gear components, etc., as they possess these properties.

Heat exchangers: Being resistant to corrosion and having high durability, Grade 316/316L is a highly reliable choice for being used in heat exchangers.

Textile industry: This type of stainless steel endures deterioration with its inherent properties of strength and high-resistance, making it the most suitable for the textile industry.

Petrol industry: Stainless steel 316 is known for the formation of oxide layers that inhibit the process of oxidation. This property is useful for the petrol industry. Moreover, the high heat resistance of the alloy makes it very suitable for the petrol industry.

Nuclear reactors: Grade 316 is known to be of big use to the nuclear industry. The nuclear reactors have to be made out of the best material to ensure safe chemical reactions.

This alloy is very resistant to corrosion, can handle extreme temperatures, is durable and holds immense strength, making it a safe choice for nuclear reactors. The high mechanical formability is very advantageous to nuclear power plants.