Properties and Composition of Type 201 Stainless Steel

Kitchen sink
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There are many different types of stainless steel, and each has its own unique composition and qualities. Depending on the chemical composition of the steel, it may be harder, stronger, or easier to work with than other types of steel. Some types of steel are magnetic, while other types are not. Different steels have different price points as well.

If you've ever cooked, driven a car, or washed your clothes in a machine, you're most likely familiar with type 201 steel, even if you don't know it by name. This type of steel has advantages that make it an ingredient in many of the tools and machines we use every day.

What Is Type 201 Stainless Steel?

Type 201 stainless steel is an alloy that contains half the nickel and more manganese and nitrogen than other popular steels. While it is less expensive than some other alloys (because of its low nickel content), it is not as easy to work or form. Type 201 is an austenitic metal because it is a non-magnetic stainless steel that contains high levels of chromium and nickel and low levels of carbon. 

Facts About Type 201 Stainless Steel

Type 201 stainless steel is a mid-range product with a variety of useful qualities. While it is ideal for certain uses, it is not a good choice for structures that may be prone to corrosive forces such as salt water.

  • Type 201 is part of the 200 series of austenitic stainless steels. Originally developed to conserve nickel, this family of stainless steels is characterized by low nickel content.
  • Type 201 can substitute for type 301 in many applications, but it's less resistant to corrosion than its counterpart, particularly in chemical environments.
  • Annealed, it is non-magnetic, but type 201 can become magnetic by cold working. Greater nitrogen content in type 201 provides higher yield strength and toughness than type 301 steel, especially at low temperatures.
  • Type 201 is not hardened by heat treatment and is annealed at 1850-1950 degrees Fahrenheit (1010-1066 degrees Celsius), followed by water quenching or rapid air cooling.
  • Type 201 is used to produce a range of household appliances, including sinks, cooking utensils, washing machines, windows, and doors. It is also used in automotive trim, decorative architecture, railway cars, trailers, and clamps. It is not recommended for structural outdoor applications because of its susceptibility to pitting and crevice corrosion.

Type 201 Stainless Steel Composition and Properties

The qualities of type 201 stainless steel are as follows:

Density (pounds/inches3): 0.283
Modulus of elasticity in tension (pounds per inches2 x 106): 28.6
Specific heat (BTU/pounds/degrees Fahrenheit): 0.12 at 32-212 degrees Fahrenheit
Thermal conductivity (BTU/hr./ft./degrees Fahrenheit): 9.4 at 212 degrees Fahrenheit
Melting point range: 2550-2650 degrees Fahrenheit

Element Type 201 (Wt.%)
Carbon 0.15 max.
Manganese 5.50-7.50 max.
Phosphorus 0.06 max.
Sulfur 0.03 max.
Silicon 1.00 max.
Chromium 16.00-18.00
Nickel 3.50-5.50
Nitrogen 0.25 max.
Iron Balance

Processing and Forming

Type 201 stainless cannot be hardened by heat treatment, but it can be hardened by cold working. Type 201 can be annealed at temperatures between 1,010 and 1,093 degrees Celsius (1,850 and 2,000 degrees Fahrenheit). In order to keep carbides in solution and avoid sensitization, rapid cooling through the carbide precipitation range 815 and 426 degrees Celsius (1,500 and 800 degrees Fahrenheit) is required. 

This grade of stainless can be both formed and drawn. Intermediate annealing may be required for severe operations as a result of type 201's high work-hardening rate. 

Type 201 stainless can be welded by all standard methods used for 18% chromium and 8% nickel stainless steels, however, inter-granular corrosion can impact the heat zone if carbon content exceeds 0.03%.