Different Types of Stainless Steel

With its hygienic and corrosion-resistant properties combined with high tensile strength, stainless steel products are used across a wide range of industries. From construction to fabrication, stainless steel alloys can provide you with the durability and aesthetically pleasing finish for your next project or design.

Stainless Steel Types/Stainless Steel Families

To distinguish different types of stainless steel, we measure the metal’s microstructure at room temperature to learn more about the overall composition. In total, there are five primary types of stainless steel.

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Ferritic Stainless Steel

With a similar structure to low alloy steels, ferritic stainless steel boasts strong resistance to corrosion cracking. Containing little to no nickel, it is a cost-effective stainless steel that typically has a significant percentage of chromium (11.2% - 19%).

Less formable than austenitic steel.
Ferritic steel is magnetic.

Austenitic Stainless Steel

Austenitic stainless steel is the most common variety of stainless steel, making up more than 70% of overall production. It’s a well-rounded stainless steel, with adequate weldability, formability, and creep resistance.

Unlike ferritic steel, austenitic varieties are for all intents and purposes non-magnetic.
When you add a large proportion of molybdenum (over 6%), the steel becomes super austenitic, which gives it better protection against crevice corrosion and cracking.

Martensitic Stainless Steel

Martensitic stainless steel contains chromium, nickel, molybdenum, and carbon, which makes for a more brittle microstructure. Martensitic stainless steel is generally tougher than the austenitic and ferritic varieties.

Though they have relatively low formability, these alloys can be tempered as you would with carbon steels.
Adding a small amount of nickel improves the martensitic steel’s lack of weldability.

Duplex Stainless Steel

These hybrid alloys are called duplex because the composition is about 50% austenitic and 50% ferritic. By combining the two microstructures, you end up with a new form that has more strength than both.

The strong composition also leads to improved corrosion resistance and stress cracking resistance.
Since duplex steel has such a large proportion of ferritic alloy, this type is also magnetic.

Precipitation Hardened Stainless Steel

This martensitic stainless steel type has been made even stronger by adding aluminum, copper, and niobium, in conjunction with a precipitation hardening process. It involves heat-treating the metal to create particles in the crystal lattice, which help to stop irregularities in the microstructure and boost the alloy’s overall strength.

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Stainless Steel Grades for Construction and Industrial Components

While there are a wide range of stainless steel grades, 300 series stainless steels are most often used for construction and building purposes. 300 series stainless steels are austenitic, offering exceptional wear resistance and surface quality.

303 Stainless Steel
- 303 stainless steel is well-suited for automotive parts and industrial components like screws, nuts, and bushings.
304/304L Stainless Steel
- As a general use stainless steel, the 304 grade is ideal for architecture, bridges, and consumer appliance applications.
316/316L Stainless Steel
- 316 stainless steel works well in marine environments as well as outdoor structures and enclosures.

Stainless Steel Shapes

Stainless steel can be manufactured in a variety of shapes and grades. Its versatility lends itself to architectural applications as well as industrial component fabrication purposes. Common stainless steel shapes include:

Differences between 304 and 316 Stainless Steel Grades

As two of the most common stainless steel grades, 304 stainless steel and 316 stainless steel have similar compositions. 316 stainless steel has less chromium but more nickel, in addition to molybdenum. Additional differences for consideration include:

316 stainless steel provides better corrosion resistance than 304 stainless steel
316 stainless steel has better heat resistance and strength when compared to 304 stainless steel
304 stainless steel is more cost-effective than 316 stainless steel
304 stainless steel provides better formability than 316 stainless steel

Find the Right Stainless Steel Product for Your Project Needs

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The 4 Different Types of Stainless Steel