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Specifications

321 stainless is a titanium stabilized grade commonly used for service in the 1000-1600°F temperature range. For service temperatures up to about 1600°F, a stabilizing treatment at 1550-1650°F, air cool, may be used to provide optimum resistance to intergranular corrosion and to polythionic acid stress corrosion cracking.

321 stainless is readily welded by all common methods including submerged arc. Appropriate weld fillers are AWS ER347 bare wire and E347 covered electrodes. 321 stainless is similar in machinability to 304 stainless steel. It has a machinability rating of 45% relative to AISI B1112.
Common Trade Names  
321, 321 Stainless, Alloy 321 
Inventory  
321 Plate, 321 Sheet, 321 Coil and 321 Bar
Specifications  
UNS S32100, Werkstoff 1.4541, EN 1.4541
ASTM: A 240, A 479, A 276,
ASME: SA-240, SA-479
AMS: 5510, 5645
GE B50T1181, GE B50T12, GE B50T81, QQS 766d, QQS 763
Chemical Composition, %  
  Cr Ni Mo Cu Ti C Mn Si P S N Fe
MIN 17.0 9.0 - - 5x(C+N) - - 0.25 - - - -
MAX 19.0 12.0 0.75 0.75 0.7 0.08 2.0 1.0 0.04 0.03 0.1 Balance
Features  
  • Oxidation resistant to 1600°F
  • Stabilized against weld heat affected zone (HAZ) intergranular corrosion
  • Resists polythionic acid stress corrosion cracking
Applications  
  • Aircraft piston engine manifolds
  • Expansion joints
  • Thermal oxidizers
  • Refinery equipment
  • High temperature chemical process equipment
Physical Properties  
Density: 0.286 lb/inch3
Melting Point: 2550 - 2600°F
Temperature, °F 200 400 800 1000 1200 1400 1600
Coefficient* of Thermal Expansion, in/in°F x 10-6 9.3 9.4 10.0 10.3 10.6 10.9 11.1
Thermal Conductivity
Btu • ft/ft2 • hr • °F
8.8 9.7 11.4 12.1 - - -
Modulus of Elasticity, Dynamic psi x 106 28.0 26.5 23.8 22.5 21.2 19.7 -
Electrical Resistivity
Temperature, °F 68 212 392 752 1112 1472 1652
ohm circ mil/ft 430 470 515 600 670 725 760
* 70°F to indicated temperature.
Mechanical Properties  
Average Elevated Temperature Tensile Properties
Temperature, °F 68 400 600 800 1000 1200 1400
Ultimate Tensile Strength, ksi 84 62 62 62 59.5 45.5 27.5
0.2% Yield Strength, ksi 38 20.5 18 17 16.5 16 14
Average Stress for Rupture
Temperature, °F 1050 1100 1150 1200 1250 1300 1350 1400 1450 1500
1,000 hours, ksi - 30 - 19 - 11.2 - 6.8 - 4.0
10,000 hours, ksi 31 23.5 17.3 12.9 9.7 7.2 5.4 4.0 3.05 2.3
100,000 hours, ksi 23 16.5 12 8.7 6.3 4.6 3.3 2.45 1.75 1.27
Average Stress for Secondary (minimum) Creep Rate
Temperature, °F 1050 1100 1150 1200 1250 1300 1350 1400 1450 1500
1% in 1,000 hours, ksi 30 20 13.1 8.8 5.8 3.85 2.55 1.7 1.13 0.75
1% 100,000 hours, ksi 13.6 9.2 5.9 3.9 2.55 1.7 1.1 0.74 0.48 0.32