321 Stainless Steel

DESCRIPTION 
Type 321 Stainless Steel is a stabilized austenitic stainless steel similar to Type 304 but with a titanium addition of at least five times the carbon content. This titanium addition reduces or prevents carbide precipitation during welding and in 800–1500°F service. It also improves the elevated temperature properties of the alloy. Type 321 provides excellent resistance to oxidation and corrosion and possesses good creep strength. It is used primarily in applications involving continuous and intermittent service temperatures within the carbide precipitation range of 800–1500°F. 
 
PRODUCT FORMS 
Sheet, Strip 
 
SPECIFICATIONS 
ASTM A240 
 
TYPICAL APPLICATIONS 
Annealing covers, high-temperature tempering equipment, diesel and heavy duty automotive exhaust systems, firewalls, stack liners, boiler casings, welded pressure vessels, jet aircraft components, radiant super heaters, bellows and oil refinery equipment. 
 
PROCESSING 
Type 321 is non-hardenable by heat treatment. Annealing: Heat to 1750–2050°F, then water quench or air cool. Forming: Type 321 can be readily formed and drawn. Like most austenitic stainless steels, Type 321 work hardens and may require annealing after severe forming. 
 
WELDING 
This alloy is generally considered to have comparable weldability to Types 304 and 304L. A major difference is the titanium addition that reduces or prevents carbide precipitation during welding. When a filler is needed, either AWS E/ER 347 or E/ER 321 is most often specified. 
 
CORROSION 
Type 321 exhibits excellent resistance to organic chemicals, dyestuffs, and a wide range of inorganic chemicals. It resists nitric acid well and the sulfur acids moderately. Long-time exposure in the 900–1500°F range may lower its general corrosion resistance, but the grade still shows improved resistance to intergranular corrosion compared to unstabilized grades. 

MECHANICAL PROPERTIES

Type  Yield Strength 0.2% offset (KSI)  Tensile Strength (KSI)  % Elongation (2” Gauge Length) 
321  30 min.  75 min.  40 min. 

CHEMICAL PROPERTIES

Element  Type 321 
Carbon  0.08 max. 
Manganese  2.00 max. 
Sulfur  0.030 max. 
Phosphorus  0.045 max. 
Silicon  0.75 max. 
Chromium  17.00 – 19.00 
Nickel  9.00 – 12.00 
Titanium 
5x(C+N) min. – 0.70 max. 
Nitrogen 
0.10 max. 

PHYSICAL PROPERTIES 
Density @ RT: 0.29 lb./in^2; Modulus of Elasticity in Tension: 28.0 psi x 10^6; Specific Heat: 0.12 BTU/°F/lb. from 32 to 212°F; Thermal Conductivity: 9.3 at 212°F and 12.8 at 932°F; Mean Coefficient of Thermal Expansion: 9.2 from 32 to 212°F, 9.5 from 32 to 600°F, 10.3 from 32 to 1,000°F, and 10.7 from 32 to 1,200°F; Electrical Resistivity: 28.4 micro ohms-cm at 70°F; Melting Point Range: 2500-2550°F. 

INformation

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Phone: 847-257-6570

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Phone: +52.811.6363844

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Phone: 615-793-4700

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