Stainless Steel 316 - Alloy Composition

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Stainless steel type 316 is part of a family of stainless steel alloys (301, 302, 303, 304, 316, 347). The 316 family is a group of austenitic stainless steels with superior corrosion resistance to 304 stainless steel. This alloy is suitable for welding because it has a carbon content lower than 301 to 303 series alloys to avoid carbide precipitation in welding applications. The addition of molybdenum and a slightly higher nickel content make 316 Stainless Steel suitable for architectural applications in severe settings, from polluted marine environments to areas with sub-zero temperatures. Equipment in the chemical, food, paper, mining, pharmaceutical and petroleum industries often includes 316 Stainless Steel.

Nominal Composition in Percentage:

            Ni                    12.00

            Cr                    17.00

            Mo                    2.50

            Fe                   Balance

            Si                     1.00

            Mn                    2.00

            C                     0.080

            P                     0.045

            S                     0.030

UNS Number:

S31600

Other Standard Specifications:

AMS 5524,-ASTM A313,ASTM A 580, MIL-S- 5059D

300 Series—austenitic chromium-nickel alloys

  • Type 301—highly ductile, for formed products. Also hardens rapidly during mechanical working. Good weldability. Better wear resistance and fatigue strength than 304.
  • Type 302—same corrosion resistance as 304, with slightly higher strength due to added carbon.
  • Type 303—free machining version of 304 via addition of sulfur and phosphorus. Also referred to as "A1" in accordance with ISO 3506.
  • Type 304—the most common grade; the classic 18/8 (18% chromium, 8% nickel) stainless steel. Outside of the US it is commonly known as "A2 stainless steel", in accordance with ISO 3506 (not to be confused with A2 tool steel).
  • Type 316—the second most common grade (after 304); for food and surgical stainless steel uses; alloy addition of molybdenum prevents specific forms of corrosion. It is also known as marine grade stainless steel due to its increased resistance to chloride corrosion compared to type 304. 316 is often used for building nuclear reprocessing plants.

Density:

8.03 g/cm3 (0.290 lbs/in2)

Exceptional Properties:

Toughness, durability, corrosion reistance, weldability