ss-321ASTM A 240, A 479, A 276
UNS S32100

321 Stainless is available in the following forms at Mega Mex

  • Stainless Steel 321 Sheet
  • Stainless Steel 321 Plate
  • Stainless Steel 321 Bar
  • Stainless Steel 321 Pipe & Tube
  • Stainless Steel 321 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)
  • Stainless Steel 321 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.