Type 321 Stainless Steel is a stabilized austenitic stainless steel similar to Type 304 Stainless Steel 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 Stainless Steel 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:
Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipes, Seamless Stainless Steel Pipe, Stainless Steel Elbow, Stainless Steel Angle Bars
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
Chemical Composition: ASTM A240ElementType 321Carbon0.08 max.Manganese2.00 max.Sulfur0.030 max.Phosphorus0.045 max.Silicon0.75 max.Chromium17.00 – 19.00Nickel9.00 – 12.00Titanium5x(C+N) min. – 0.70 max.Nitrogen0.10 max.
Mechanical Properties:TypeYield Strength 0.2% offset (KSI)Tensile Strength (KSI)% Elongation (2″ Gauge length)Hardness Rockwell32130 min.75 min.40 min.HRB 95 max.
Physical Properties:Density (lb./ in^2) @ RT 0.29Modulus of Elasticity in Tension (psi x 10^6) 28.0Specific Heat (BTU/o F/lb.)32 to 212 oF0.12Thermal Conductivity (BTU/hr/ft^2/ft)212oF9.3 932oF12.8Mean Coefficient of Thermal Expansion (in. x 10^-6 per o F)32 to 212oF9.2 32 to 600oF9.5 32 to 1,000oF10.3 32 to 1,200oF10.7Electrical Resistivity (micro ohms – cm)at 70oF28.4Melting Point Range (oF) 2500 – 2550
APPLICATIONS
Ball Valves Stainless Steel Pipes
Airplane exhaust manifolds Mechanical Seals Heat Exchangers Stainless Steel Pipe Fittings
Boiler shells Process equipment
Stainless Steel Angle Bars
Expansion joints Flexible couplings Pressure vessels Stainless Steel Flanges
Cabin heaters Fire walls
Processing:
Type 321 Stainless Steel 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 Stainless Steel work hardens and may require annealing after severe forming.
Welding:
This particular alloy is generally considered to have comparable weldability to Types 304 Stainless Steel and 304L Stainless Steel. 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 Stainless Steel or E/ER 321 Stainless Steel is most often specified.
Corrosion:
Type 321 Stainless Steel 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.
Source: wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)
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