Types & Grades of Stainless Steel & Their Uses

Stainless steel is known for being strong, long-lasting, and looking good in almost any situation. It is one of the most versatile materials, with uses ranging from medical equipment and cutlery to auto trim and airport roofs. But that doesn’t mean it’s all the same! Different types and grades of stainless steel have different properties that make them perfect for various applications.

In this article, New Mexico Metals LLC – the leading stainless steel supplier Albuquerque area will give you a crash course in stainless steel grades and their uses. But before we start, let’s first look at the types of stainless steel to lay the foundation for this discussion.

Types

Stainless steel is an iron alloy made up of several elements, including chromium, nickel, and carbon, which gives it its strength and resistance to corrosion. Depending on the concentration of these elements, stainless steel can be divided into three different types:

1.    Austenitic

This stainless steel contains high amounts of chromium (16-26%) and nickel (up to 35%), making it the most corrosion-resistant type. It is also non-magnetic and has good formability, making it very popular in various applications.

2.    Ferritic

This steel contains low amounts of carbon (less than 0.2%), chromium (10.5-26%), and zero nickel. These properties make ferritic steel magnetic. However, it offers less corrosion resistance compared to austenitic.

3.    Martensitic

With a medium carbon concentration (0.2-1%), martensitic steel contains high levels of chromium (11.5-18%) and less amount of nickel (0.2-1%). This steel offers good ductility, strength, and magnetism while maintaining moderate corrosion resistance.

Grades and Uses

Now that we understand the properties of each stainless steel, let’s dive deeper into the grades of each type and their uses.

Grades (304 and 316)

They are classified under austenitic stainless steel.

Grade 304 is the most popular stainless steel, well known for its excellent corrosion resistance and formability. Although it is susceptible to chloride stress corrosion cracking, 304 steel offers good rusting resistance to mild chemicals and food acids, making it ideal for applications such as cookware, kitchen sinks, and outdoor architectural features.

Grade 316 is the second most popular grade, offering superior corrosion and pitting resistance to much stronger chemicals (including chlorides). This makes it ideal for marine and offshore applications.

Grades (409/410L, 430, 430Ti, 439, 441, 434, 436, 444, 446, 445, and 447)

These are all ferritic stainless-steel grades. However, they are classified into five major groups:

• Group 1 (409/410L)
• Group 2 (430)
• Group 3 (430Ti, 439, and 441)
• Group 4 (434, 436, and 444)
• Group 5 (446, 445, and 447)

Group 1 contains the least amount of chromium. These grades are best suited for environments where localized rust is a concern. Common uses include automotive exhaust systems and heaters.

Group 2 contains higher amounts of chromium, making them ideal for applications where good corrosion resistance is necessary. They are commonly used for kitchen sinks, cutlery, and indoor panels.

Group 3 offers better formability and corrosion resistance than group 2. They are commonly used as a replacement for grade 304 in several applications, including kitchen sinks and home appliances.

Group 4 contains moderate levels of molybdenum, enhancing their corrosion resistance. These grades are commonly used in automotive exhaust systems, hot water tanks, and heaters.

Group 5 offers the greatest corrosion resistance of all ferritic grades. They contain the highest amount of chromium and molybdenum and are commonly used in chemical processing equipment and marine applications.

Grades (410, 420, and 440)

They are classified under martensitic stainless steel.

Generally, they offer excellent tensile strength and excellent wear and impact resistance. They provide less corrosion resistance to strong chemicals (compared to austenitic and ferritic grades) but are resistant to mild: acids, alkalis, and food compounds.

This makes them ideal for cutlery, surgical tools, and machine parts applications.

Final Thoughts

Choosing the right grade of stainless steel for your application can be difficult. However, understanding the properties of each type can help make the selection process much easier. By utilizing the information provided above, you can be sure to select the most suitable grade for your next project.

If you have any questions about stainless steel or need help finding the right grade for your project, don’t hesitate to get in touch with New Mexico Metals LLC. We are the leading stainless steel supplier Albuquerque area and can provide you with all the stainless-steel information and products you need.

Contact us today to learn more about our services!