321/H 1.4541/1.4878 Stainless Steel | Intamet Ltd

321/321H is a strong stainless steel alloy that resists corrosion and performs well in high temperatures.

321/321H is a strong stainless steel alloy that can withstand high temperatures and is resistant to corrosion in hot environments. It is a variation of the standard 321 alloy, which is stabilised with titanium to improve its intergranular corrosion resistance. The H in 321H stands for "high carbon" which indicates that the alloy has a higher carbon content than standard 321 alloy.

The alloy is very resistant to rust, especially in hot places like the aerospace and petrochemical industries. It also has a good resistance to intergranular corrosion and is resistant to pitting and crevice corrosion in chloride-containing environments. The alloy is strong at high temperatures. It can be used for exhaust manifolds, furnace parts, and heat exchangers.

321H alloy has a higher carbon content than standard 321 alloy which gives it a higher strength and improved high-temperature properties. It is often used for items that require strength and resistance to rust and heat. These items include furnace parts, heat exchangers, and exhaust systems that need to withstand tough conditions.

321/321H alloy is a strong and corrosion-resistant alloy, suitable for various high-temperature uses. It comes in different forms like sheet, plate, and pipe, and can be easily welded and shaped to meet specific needs.

Physical & Mechanical Properties of 321/321H

Physical Properties:

  • Density: 0.28 lb/in3 (7.99 g/cm3)
  • Melting point: 2550-2650°F (1399-1454°C)

Mechanical Properties:

  • Tensile strength: 90 ksi (620 MPa)
  • Yield strength: 45 ksi (310 MPa)
  • Elongation: 40%
  • Hardness: Rb 95
  • Impact strength: 20 ft-lb (27 J)

321/321H is rust resistant and has strong properties.

This makes it ideal for hot applications such as furnace parts, heat exchangers, and boilers.

Variants of 321

There are several variants of stainless steel 321, each with slightly different chemical compositions and properties. Some examples include:

  • 321F: This variant is a stabilised version of 321 and is used in applications where high temperatures are a concern. It is stabilised with titanium to prevent carbide precipitation.
  • 321L: This variant has lower carbon content than 321 and 321H, which makes it more resistant to intergranular corrosion. It is often used in welding applications.
  • 321H: As I mentioned before, this variant has higher carbon content than 321, which improves its high temperature strength.
  • 321Ti: This variant is similar to 321F but uses titanium instead of niobium as the stabilising element.
  • 321LN: This variant is a low-carbon, nitrogen-strengthened version of 321. It offers improved toughness and resistance to intergranular corrosion.

Chemical Composition of 321/321H

Chemical Composition of 321/321H

The chemical composition of 321 stainless steel, also known as UNS S32100 or 1.4541, is as follows:

  • Carbon (C): 0.08% max
  • Manganese (Mn): 2.00% max
  • Silicon (Si): 1.00% max
  • Phosphorus (P): 0.045% max
  • Sulfur (S): 0.03% max
  • Chromium (Cr): 17.0-19.0%
  • Nickel (Ni): 9.0-12.0%
  • Titanium (Ti): 5xC min
  • Iron (Fe): balance

The chemical composition of alloy 321H (UNS S32109) and 1.4878 is as follows:

Carbon: 0.04-0.10%
Manganese: 2.00% maximum
Phosphorus: 0.045% maximum
Sulfur: 0.030% maximum
Silicon: 0.75% maximum
Chromium: 17.00-19.00%
Nickel: 9.00-12.00%
Titanium: 5x(C+N) 0.70% maximum
Nitrogen: 0.10-0.25%
Iron: Balance

Alloy 321H contains small amounts of columbium and tantalum, typically around 0.10% each. These elements enhance its stability when exposed to high temperatures.

The alloy's composition may differ a bit based on the manufacturer and the specific grade of the alloy. It is always recommended to consult the manufacturer's data sheet for the exact composition of the alloy in a given application.

321 and 321H are both variations of the alloy known as stainless steel 321. They have similar chemical compositions and are often used interchangeably in industry.

The main difference between the two is that 321H has a higher carbon content, which gives it improved high-temperature strength.

Different variants of 321 are used for various applications and environments. It's crucial to choose the right one based on specific requirements.


Intamet offers 314 in a wide range of forms, including the below:

Stacked Pipes

Tubes & Pipes


Fitting & Flanges


Round Bars


Sheet & Plate