Type 321 (UNS S32100/1.4541)

  • Temperature Range: 800-1500 Degrees Fahrenheit
  • Corrosion Resistance of Intergranular Variant
  • Creep & Stress Rupture Better than 304L/304
  • High resistance to heat for better molding capacity
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The alloy 321, also known as UNS S32100, has amazing resistance to any intergranular corrosion post-exposure to 800-1500°F temperatures. This titanium stabilized alloy can easily resist oxidation along with a higher creep & stress rupture property when compared to the alloys 304 or 304L.

Not just that, the alloy also packs in a good amount of toughness in low temperatures. However, Stainless Steel Grade 321 cannot actually be hardened with the help of heat treatment. It can only be done with the cold working process.

Common Names:

  • ATI 321

Executive Standards:

  • ASTM A 276
  • ASME SA 240
  • UNS S32100
  • UNS S32109
  • ASTM A 479
  • ASME SA 167
  • ASTM A 167
  • ASTM A 240
  • AMS 5510
  • AMS 5645

Chemical Properties:

Here are some of the chemical properties of Stainless Steel Type 321 grade.



Minimum: 17.0

Maximum: 19.0

Minimum: 9.0





Max: 0.75Maximum: 2.0Maximum: 0.045Maximum: 0.03

Mechanical Properties:

When talking about the Stainless Steel Type 321, the mechanical properties of the same have been listed below:

GRADEMin TENSILE STRENGTH (MPa)Min YIELD STRENGTH 0.2% Proof (MPa)Elongation(Percent in 50 mm) MinMax HARDNESS


(HR B)




321 H5152054095217

Physical Properties:

While most people interchange the terms of physical and mechanical properties, they are truly different from one another. So, here are some physical properties of Stainless Steel Grade 321.

  • Density (Kg/m3):8027
  • Elastic Modulus (GPa): 193
  • Mean Co-Efficient of Thermal Expansion(μm/m/°C) (0-100) °C:6
  • Mean Co-Efficient of Thermal Expansion(μm/m/°C) (0-315) °C: 2
  • Mean Co-Efficient of Thermal Expansion(μm/m/°C) (0-538) °C: 6
  • Thermal Conductivity (W/m.K) (At 100°C):1
  • Thermal Conductivity (W/m.K) (At 500°C): 2
  • Specific Heat (0-100)°C (J/kg.K): 500
  • Electrical Resistivity (nΩ.m): 720

Key Features:

Some of the popular reasons for people to select the 321 Stainless steel grade has been listed here. Check out the key features below:

  • Corrosion Resistance: Stainless Steel 321 doesn’t erode easily due to moisture or oxygen like iron does.
  • Heat Resistance: This alloy has a wide-scale application due to its ability to withstand high temperatures.
  • Excellent Welding Capacity: Stainless steel 321 is easily weldable. However, there is a need for type 347 as filler.

Product Forms Available:

The Stainless Steel 321 Type is available as an alloy that is stabilized with the use of titanium and can be purchased in its solid state.


With Type 321 Stainless Steel, the typical everyday applications include:

  • Expansion Joints
  • Manifolds of Aircraft Exhaust
  • Furnace Parts
  • Bellows
  • Heat Exchangers
  • Tubing for Heating Element
  • Welded or Woven Screens for the high-temperature based mineral processing
  • Spiral-Shaped Welded Tube Designed for Burner Flues and Pipes

Possible Alternative Grades:

In case you do not wish to use the Stainless Steel Type 321 variant, there are multiple variants you can opt for. Here are some popular alternatives and the reasons to choose them.

  • 3CR12 Grade: With 3CR12, you get access to a mildly high temperature that goes up to 600 degrees centigrade.
  • 304L Grade: It is used for intergranular corrosion resistance as opposed to its high-temperature based strength.
  • 304H Grade: With 304H, only mildly high temperature can be accessed. This temperature goes as high as 800 degrees centigrade.
  • S30815 (253MA) Grade: With this grade of stainless steel, you get an operating environment temperature that goes as high as 1150 degrees centigrade.
  • 310: With the 310, you get an operating environment temperature that goes as high as 1100 degrees centigrade.


1-How is stainless steel 316 different from 321?

The prime difference between the two is their overall carbon content. While 316 is packed with higher corrosion resistance, the 321 show better resistance to the corrosion of the inter-crystalline pattern, especially in a higher temperature range.

2-How is stainless steel 304 different from 321?

Stainless steel 304 is a low-carbon based alloy that is heat resistance due to the presence of chromium and nickel. On the other hand, Stainless Steel 321 houses chromium-nickel alloy with titanium combination.

3-Which grade of stainless steel is the best-known type?

Stainless Steel Type 304 is the most popular and best grade with a composition comprised of 18 percent chromium & 8 to 10 percent nickel, respectively.

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