Type 201 (UNS S20100) Description
Type 201 is an austenitic chromium-nickel-manganese stainless steel that was developed in the 1950’s due to worldwide nickel shortages. In the Type 201 composition, manganese and nitrogen are partially substituted for nickel. T201 addresses the volatility of nickel prices while offering comparable corrosion resistance and formability to T301 and T304 and has become a viable lower cost alternative to these austenitic grades. Type 201 can be used in many applications because of its wide range of mechanical properties in the annealed and cold worked condition. Type 201 is non-magnetic in the annealed condition but becomes magnetic as a result of cold working.
Chemical Composition
Chemical Composition (wt%) limits as specified in ASTM A240 and ASME SA240*
Element |
201 |
Carbon |
0.15 |
Chromium |
16.0-18.0 |
Nickel |
3.5-5.5 |
Manganese |
5.50-7.50 |
Silicon |
1.00 |
Nitrogen |
0.25 |
Phosphorus |
0.060 |
Sulfur |
0.030 |
Mechanical Properties
Mechanical property requirements for annealed product as specified in ASTM A240 and ASME SA240
Property |
201 |
Yield Strength, min. (ksi) |
45 |
Tensile Strength, min. (ksi) |
95 |
Elongation, min. (%) |
40 |
Hardness, max. (Rb) |
100 |
Fabrication
Type 201 Stainless Steel can be fabricated by bench forming, roll forming and brake bending in much the same manner as Type 301. However, because of its higher strength, it may exhibit greaterspringback. This material can be drawn similarly to Type 301 in most drawing operations if more power is used and the hold-down pressure is increased.
Heat Treatment
Type 201 is not hardenable by heat treatment. Annealing: Anneal at 1850 – 1950 °F (1010 – 1066 °C), then water quench or rapidly air cool. The annealing temperature should be kept as low as possible, consistent with the desired properties, because Type 201 tends to scale more than Type 301.
Weldability
The austenitic class of stainless steels is generally considered to be weldable by the common fusion and resistance techniques. Special consideration is required to avoid weld “hot cracking” by assuring formation of ferrite in the weld deposit. As with other chrome-nickel austenitic stainless steel grades where carbon is not restricted to 0.03% or below, the weld heat affected zone may be sensitized and subject to intergranular corrosion in some environments.This particular alloy is generally considered to have poorer weldability to the most common alloy of this stainless class, Type 304L Stainless Steel. When a weld filler is needed, AWS E/ER 308 is most often specified. Type 201 Stainless Steel is well known in reference literature and more information can be obtained in this way.