UNS S32100
ASTM A 240, A 479, A 276
321 Stainless is available in the following forms
• Sheet
• Plate
• Bar
• Pipe & Tube
• Fittings (i.e. flanges, slip-ons, blinds, weld-necks, lapjoints, long welding necks, socket welds, elbows, tees, stub-ends, returns, caps, crosses, reducers, and pipe nipples)
• Weld Wire
321 Stainless Steel Overview
Stainless 321 is a heat resistant, titanium stabilized, austenitic alloy that's commonly used for service in the 1000°-1600°F temperature range. 321 stainless is primarily used in applications that involve continuous and intermittent service temperatures within the carbide precipitation range of 800°-1500°F. Type 321 is similar to type 304 stainless 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 the 800°-1500°F service conditions. In order to provide optimum resistance to intergranular corrosion and to polythionic acid stress corrosion cracking in service temperatures at 1500°-1650°F an air cool may be used.
What are the characteristics of 321 Stainless?
• Oxidation resistant to 1600°F
• Stabilized against weld heat affected zone (HAZ) intergranular corrosion
• Resists polythionic acid stress corrosion cracking
Stainless 321 Chemical Composition, %
|
|
Cr
|
Ni
|
Mo
|
Cu
|
Ti
|
C
|
|
MIN
|
17.0
|
9.0
|
-
|
-
|
5x(C+N)
|
-
|
|
MAX
|
19.0
|
12.0
|
0.75
|
0.75
|
0.70
|
0.08
|
|
|
Mn
|
Si
|
P
|
S
|
N
|
Fe
|
|
MIN
|
-
|
0.25
|
-
|
-
|
-
|
-
|
|
MAX
|
2.0
|
1.0
|
0.04
|
0.03
|
0.1
|
Bal
|
What applications might 321 Stainless Steel be used?
• Aircraft piston engine manifolds and exhaust stacks
• Expansion joints
• Thermal oxidizers
• Refinery equipment
• High temperature chemical process equipment
Mechanical Properties
Average Elevated Temperature Tensile Properties
|
Temperature, °F
|
Ultimate Tensile Strength, ksi
|
.2% Yield Strength, ksi
|
|
68
|
84
|
38
|
|
400
|
62
|
20.5
|
|
600
|
62
|
18
|
|
800
|
62
|
17
|
|
1000
|
59.5
|
16.5
|
|
1200
|
45.5
|
16
|
|
1400
|
27.5
|
14
|
Welding Stainless Steel 321
321 Stainless is readily welded by all common methods including submerged arc. Appropriate weld fillers are most often specified as AWS E/ER 347 or E/ER 321.
This alloy is generally considered to have comparable weldability to 304 and 304L stainless with the main difference being the titanium addition which reduces or prevents carbide precipitation during welding.
