Type 201 Stainless Steelis an austenitic chromium-nickel-manganese
stainless steel which was developed to conserve nickel. Type 201 is
a lower cost alternative to conventional Cr-Ni stainless steels
such as 301 and 304. Nickel is replaced by additions of manganese
and nitrogen. It is non-hardenable by thermal treatment, but may be
cold worked to high tensile strengths. Type 201 is essentially
nonmagnetic in the annealed condition and becomes magnetic when
cold worked. Type 201 can be substituted for Type 301 in many
applications.
Specifications
ASTM A240, A666
Typical Applications
Typical applications for Types 201 are cookware, hose clamps,
piston rings, transit car structural member, transit car
roofing/siding, thermal window spacers, air bag containers, and
truck trailer posts and door frames.
Chemical Composition
Element | Type 201 |
Carbon | 0.15x |
Manganese | 5.5 - 7.5 |
Sulfur | 0.03X |
Phosphorus | 0.060x |
Silicon | 1.0 x |
Chromium | 16 - 18 |
Nickel | 0.6-5.5 |
Nitrogen | 0.25x |
Mechanical Properties
Type | Yield Strength 0.2% offset (KSI) | Tensile Strength (KSI) | % Elongation(2" Gauge length) | Hardness Rockwell |
201 Ann | 38 min. | 75 min. | 40% min. | HRB 95 max. |
201 ¼ Hard | 75 min. | 125 min. | 25.0 min. | 25 – 32 HRC (typical) |
201 ½ Hard | 110 min. | 150 min. | 18.0 min. | 32 - 37 HRC (typical) |
201 ¾ Hard | 135 min. | 175 min. | 12.0 min. | 37 – 41 HRC (typical) |
201 Full Hard | 145 min. | 185 min. | 9.0 min. | 41 – 46 HRC (typical) |
Physical Properties
Density (lb./ in^2) @ RT | | 0.283 |
Modulus of Elasticity in Tension (psi x 10^6) | | 28.6 |
Specific Heat (BTU/°F/lb.) | 32 to 212 °F | 0.12 |
Thermal Conductivity (BTU/hr/ft^2/ft) | 212°F | 9.4 |
Mean Coefficient of Thermal Expansion (in. x 10^-6 per °F) | 32 to 212°F | 8.7 |
| 32 to 600°F | 9.7 |
| 32 to 1,000°F | 10.2 |
Electrical Resistivity (micro ohms - cm) | at 70°F | 69 |
Melting Point Range (°F) | | 2550/2650 |
Oxidation Resistance - Continuous Service(°F) | | 1550 |
Oxidation Resistance - Intermittent Service(°F) | | 1500 |
Processing
The annealing temperature for Type 201 is between 1850-2000°F.
Rapid cooling through the carbide precipitation range (1500 – 800
°F) is necessary to keep the carbides in solution and prevent
sensitization. Type 201 is not hardenable by thermal treatment; it
is only hardenable by cold working.
Forming
Type 201 has similar bending, forming and drawing characteristics
to Type 301 stainless steel
Welding
Type 201 can be welded by all conventional methods applied to 18
percent chromium, 8 percent nickel steels. Filler metal of the
conventional chromium-nickel analyses can be used. Like other
austenitic stainless steels where carbon is not controlled below
0.03%, Type 201 is susceptible to intergranular corrosion in the
weld heat affected zone.
Corrosion
Type 201 is resistant to a wide variety of mild to moderately
corrosive environments. It has corrosion resistance approaching
that of Types 301and has been successfully substituted for 304 in
many mild environments.
