Comparing Stainless Steel Types: 301, 304, 316 & 321

Not all stainless steels were made the same, but they’re also not too different. So, how do you tell them apart and find the best one for your needs? We compare the benefits and applications of four of the most common austenitic stainless steels.

The 5 grades of stainless steel

There are five grades of stainless steel, categorised primarily by their chemical compositions. The grades are:

  • Austenitic
  • Ferritic
  • Martensitic
  • Duplex
  • Precipitation hardening

Each category has specific uses which it is best designed for. While they all have important uses, around 95% of stainless steel we use is from the austenitic and ferritic grades.

What are austenitic steels?

Austenitic steels are classified in the 200-300 series and typically feature 17-25% chromium, 8-20% nickel, plus a mix of other elements. They’re known for their easy ability to form or weld and high corrosion resistance. At Airport Metals, we stock many common austenitic steels in sheets, tubing and rods. Browse our stock list for a comprehensive list of all steel grades and specifications.

Comparing our steel types

Below is a comparison of the properties and uses for four common steels: 304, 316, 301 and 321.

304

This is the most commonly used stainless steel in the world, used for everything from household appliances to computers and tech, industry equipment and of course, aircrafts and motorsports. It’s sometimes referred to as 18/8 steel due to its 18% chromium and 8% nickel composition.

316

This is the next most common grade and is noted for its high molybdenum content which improves the corrosion resistance. It’s also known as “marine grade” steel due to its high resistance to chloride corrosion.

301

The lowest chromium-nickel blend of all those mentioned here, and sometimes the most cost-effective for this reason. It’s stronger than 304 steel (120 ksi compared to 90 ksi) and has better wear resistance.

321

This follows the basic composition of 304 but is additionally stabilised with titanium. This creates very high heat resistance, up to 900°C, and a lower risk of weld decay than 304 steel.

Find the ideal stainless steel for your needs

Airport Metals have been supplying quality stainless steel products throughout Australia for over 50 years. Our expert teams know which steel grade is best for your needs and can easily advise on your upcoming projects. For general enquiries or to place your order, call (03) 9310 5566 or send a message online.

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