Stainless steel isn’t a single alloy and it comes with over 100 different grades. Determining the proper alloy for your product is a crucial first step.

1. Introduction

While stainless steel grades have some common characteristics, differences among the grades is essential to find the optimal type for the right task. Although the fabrication of stainless steel is increasing over the years, stainless steel is not a single alloy material. Although the corrosion resistance is derived from the chromium content, there are multiple ingredient combinations available for trading.

2. Stainless Steel Alloys

• Austenitic Stainless Steel

Austenitic Stainless Steel is the most used and popular grade around the world. Although it often includes chromium and nickel, some grades also include manganese and molybdenum. These alloys are nonmagnetic but depending on the nickel content and other composition factors, they can become slightly magnetic. Heat-based hardening will not work with these types of steel. They offer great corrosion resistance, formability and weldability.

Popular grades of these alloys are 303, 304, 316 grades.

• Ferritic Stainless Steel

These alloys contain 10.5%-20% chromium for corrosion protection and they are prone to high temperatures. Heat treating won’t harden them, and they are good magnetic. Ferritic stainless is used in cases where corrosion resistance is essential. They have low nickel content, which makes them a cost effective alternative.

Most of the grades with this alloy are magnetic and have good corrosion resistance, formability and weldability.

• Duplex Stainless Steel

Duplex stainless steels are a combination of austenitic and ferritic alloys. Duplex stainless steels offer strength, durability, and improved resistance to chlorides. They have good weldability and formability in comparison to other alloys. Their improved corrosion resistance make them attractive for petrochemical and offshore applications. Common duplex alloys include are 318L, LDX 2101, LDX 2304, 2507 grades.

• Martensitic Stainless Steel

This is the least common type of alloy with moderate corrosion resistance. They contain around 11%-18% chromium and higher carbon compared to other alloys. They are difficult to weld but heat treatable. It is popular amongst sharp edge goods such as knives, razors due to their ability of tempering and hardening.

Common grades of martensitic steels are 410 and 420 grades.

3. Conclusion

Stainless steel come in many alloys and grades. It’s important to understand the unique features of different stainless steel alloys to not only ensuring long-lasting performance, but also optimize the cost.