What Is 201 Stainless Steel? Composition, Properties and Typical Applications

What Is 201 Stainless Steel?

201 stainless steel is an austenitic chromium-nickel-manganese alloy originally developed to conserve nickel. In the standard composition, part of the nickel of the 304 family is replaced by manganese and nitrogen, which stabilize the austenitic structure at lower cost. The grade is covered by ASTM A240 as UNS S20100, by JIS G4303 and G4304 as SUS201, and by GB standards in China as 12Cr17Mn6Ni5N. It is supplied as plate, sheet, strip, coil, tube, pipe and bar. Because of its lower nickel content, 201 costs less than 304, but it also has lower corrosion resistance, particularly in chloride and marine environments, and it develops magnetism more readily after cold working.

Chemical Composition (ASTM A240 / JIS G4304)

Element	201 (UNS S20100) wt%
Carbon (C)	0.15 max
Manganese (Mn)	5.50 - 7.50
Phosphorus (P)	0.060 max
Sulfur (S)	0.030 max
Silicon (Si)	0.75 max
Chromium (Cr)	16.0 - 18.0
Nickel (Ni)	3.5 - 5.5
Nitrogen (N)	0.25 max

Compared with 304, the nickel content is roughly halved and replaced by manganese in the 5.5-7.5% range plus nitrogen up to 0.25%. JIS SUS201 allows silicon up to 1.00% and is otherwise equivalent.

Mechanical Properties and Physical Behavior

Property	ASTM A240 (201)	JIS G4304 (SUS201)
Tensile strength, min MPa	655	520
Yield strength, min MPa	310	275
Elongation, min %	40	40

201 is characterized by high tensile strength and an exceptionally high work-hardening rate. It can be strengthened substantially by cold working, which is exploited in springs, fasteners and structural sheet applications. After cold working, the alloy becomes noticeably magnetic even though it is fully austenitic in the annealed condition. Ductility after cold working remains good, and toughness is adequate for indoor service.

201 vs 304: Key Differences

Aspect	201	304
Nickel content	3.5 - 5.5%	8.0 - 10.5%
Relative cost	Lower	Higher
Tensile strength	Higher minimum	Lower minimum
Chloride corrosion resistance	Lower	Higher
Magnetism after cold work	Noticeable	Slight

For dry indoor use, 201 can substitute for 304 in many non-corrosive duties at lower cost. In moist, coastal, chemical or food-contact service, 304 or a molybdenum-bearing grade is required because 201 is more susceptible to pitting and rusting.

Typical Applications and Limitations

Typical applications of 201 include kitchen equipment and utensils, appliance cabinets and liners, sinks and countertops for dry interior use, indoor architectural panels and handrails, automotive trim and wheel covers, railway interior panels, fasteners, springs and welded tubes for light structural duty. The main limitation is corrosion performance: 201 should not be used in chloride-rich environments, outdoor coastal installations, swimming pool atmospheres or applications requiring food-contact approval under strict hygiene regulations, where 304 or 316 is the established choice.

Frequently Asked Questions

Is 201 stainless steel food grade?

201 is used for some food-contact utensils in dry service, but it is not generally accepted for sanitary food processing equipment. Regulations and industry practice favor 304 or 316 for food contact because of their higher corrosion resistance and established cleanability.

What is the difference between 201 and 304 stainless steel?

201 uses manganese and nitrogen to replace roughly half of the nickel content of 304. This makes 201 cheaper and slightly stronger, but less corrosion resistant, especially in chloride and moist environments.

Is 201 stainless steel magnetic?

In the annealed condition it is essentially non-magnetic. After cold working, such as bending or drawing, it becomes noticeably magnetic because of strain-induced martensite formation.

Can 201 stainless steel be used outdoors?

In dry, low-pollution outdoor environments 201 can give acceptable service, but in coastal areas or where de-icing salts are used it will pit and rust much faster than 304. For outdoor chloride exposure, select 304 or 316.

Can 201 stainless steel be welded?

Yes, 201 can be welded with austenitic stainless steel procedures. The high work-hardening rate means cutting and forming require more force, and welded joints in corrosive service should be avoided because the low nickel content limits corrosion performance of the weld zone.

What are the equivalent designations of 201?

201 is UNS S20100 in ASTM A240, SUS201 in JIS G4303/G4304, and 12Cr17Mn6Ni5N in Chinese GB standards. These designations refer to the same nominal composition family.