Learning About Stainless Steel Classes, Part 2

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Learning About Stainless Steel Classes, Part 2

In part one of this two-part blog, we went over some of the classes of stainless steel. Stainless steel is one of the most common types you can buy, with numerous qualities that make it perfect for a variety of applications.

At Wasatch Steel, we can help you choose the perfect kind of steel for your next project. Today, we’ll go over three more types of stainless steel and what they’re good for – including the most commonly used type out there to start us off.

Austenitic Stainless Steel

That’s right, austenitic steels are easily the most commonly used class here. This is likely due to high corrosion resistance and mechanical properties, which are promoted by increased chromium and nickel content. Austenitic stainless steels are not magnetic, which makes them easy for various treatment processes – although they cannot be hardened using heat-treatment, rather only by cold-working.

Rather than looking at particular types of austenitic stainless steel, let’s go over the three basic grades it’s found in:

  • Standard grades: There’s no minimum carbon requirement for standard grades of austenitic stainless steel, but the maximum is 0.08 percent.
  • Low carbon grades: In some cases, you may desire better corrosion resistance after welding – this is where low carbon grades are valuable. Stainless steel grades with an “L” after them indicate low carbon, or levels under 0.03 percent. This avoids an effect called carbide precipitation, which leads to corrosion.
  • High carbon grades: In other cases, the letter “H” is used after a grade to indicate at least 0.04 percent carbon, and as much as 0.10 percent. This is for steels that need to retain their strength at very high temperatures.

Duplex Stainless Steel

Duplex steels are also called ferritic-austenitic stainless steels, and they combine elements of both materials here. These are extremely strong grades, with better toughness and ductility than ferritic grades, but they still aren’t quite up to the par of austenitic grades themselves. A few common grades used:

  • Type 2205: This is the most common type, and is perfect for highly corrosive or high-pressure environments. It has low thermal expansion properties and high thermal conductivity properties. It should only be used in temperatures below 315 degrees Celsius.
  • Type 2304: Strong corrosion resistance and excellent yield strength, this material has great weldability and machinability and is very easy to fabricate.
  • Type 2507: An extremely strong steel that’s used in areas like seawater equipment and chemical processes. It comes with high levels of chromium, nitrogen and molybdenum, all of which help it resist corrosion and pitting.

Precipitation-Hardening Stainless Steel

These are stainless steels that are able to be strengthened or hardened using heat treatment, allowing for better properties. Types 17-4 and 15-5 are commonly used depending on the corrosion resistance needed.

For more on the various classes of stainless steel, or to learn about any of our steel services or steel products, speak to the pros at Wasatch Steel today.