Different Types of Stainless SteelLast updated on 7/18/2018
Stainless steel is an alloy of several different types of metal that, when combined, are stronger and more durable than when they are separate. By adding and subtracting various elements to stainless steel, engineers have been able to create many different varieties of the alloy, each with their own characteristics and uses. Stainless steel is a versatile metal and can be used for many different things ranging from construction to kitchen equipment. Many different types of stainless steel grades are used in foodservice establishments, and each type has its own pros and cons. To make an informed decision when purchasing food grade stainless steel equipment, you should understand the major elements in the alloy, the different grading systems, and the main types of stainless steel.
Important Terms and Elements
When describing different types of food grade stainless steel and their properties, there are a few key terms and elements that come up regularly. Here are some definitions of what those terms mean and what kind of effect those elements will have on the steel.
- Stainless Steel: Stainless steel is a durable and affordable metal that is used for a wide variety of purposes. It's strong, making it perfect for construction purposes, and it's corrosion resistant, so it can last a long time without being replaced or breaking.
- Corrosion: Corrosion describes the natural process where stainless steel breaks down into a more chemically stable form. The most common and well-known form of corrosion is rust. Stainless steel is inherently more resistant to corrosion than other metals, but it will eventually corrode. There are factors that can speed up corrosion as well, such as exposure to salt, excess moisture, or harsh acids.
- Alloy: An alloy is a metal that is made by combining several types of metal together. For example, stainless steel is not found naturally but is made by combining iron, carbon, and various other metals.
- Element: "Element" is a chemistry term that refers to atoms that have the same number of protons. Elements are the most basic form of substances, and they are combined to form an alloy. Some common elements you may have heard of are oxygen, carbon, nitrogen, and iron.
- Chromium: Chromium is an essential element for stainless steel, and it helps make the steel resistant to stains, tarnishing, as well as corrosion.
- Nickel: When nickel is added to stainless steel, it brings stability and strength to the metal. Another benefit of adding nickel to food grade stainless steel is it makes the steel shiny and lustrous, which is an essential quality for flatware.
- Carbon: Adding carbon to stainless steel hardens and strengthens the steel and reduces wear. Food grade stainless steel with high levels of carbon is often used for making chef knives, as knives need to be strong, durable, and able to retain an edge.
Benefits of Food Grade Stainless Steel in the Foodservice Industry
1. Corrosion resistance: Stainless steel is especially resistant to corrosion and rusting compared to other metals, which makes it perfect for use in the kitchen. Food grade stainless steel is often used for kitchen equipment, which is costly to replace. But, because most stainless steel grades are highly corrosion resistant, you won't have to worry about replacing your equipment as frequently.
2. Strength: Food grade stainless steel is strong, and it's an excellent material to use in heavy-duty equipment or in shelving for storage areas.
3. Ease of cleaning: Other materials, such as wood or plastic, have grooves or openings where bacteria can invade and grow. Stainless steel is smooth and doesn't provide a place for bacteria to hide, allowing you to clean them away easily, which is an essential benefit for foodservice.
4. Non-reactive surface: Stainless steel is a non-reactive metal, which means that you can use it to cook foods that are acidic like citrus, tomatoes, and vinegar. Other metals, like aluminum and iron, are reactive and cooking acidic foods in these metals will affect the flavor and damage the surface of the metal.
Systems for Stainless Steel Grades
There are many different types of stainless steel, and the differences can vary greatly between types. To better differentiate between different types of stainless steel, they are split up into grades. There are many different grading systems that are used by different countries and in different settings. For the foodservice industry, there are two stainless steel grades that you should know to best which are SAE grades and flatware grades.
- SAE Grades: This grading system is implemented by SAE International, an organization of engineers that develops standards for professionals in various manufacturing industries. To distinguish between stainless steel grades, their system uses whole numbers to categorize the different types. You may also see this grading system called the AISI system, which refers to the American Iron and Steel Institute, which originated this system, although it's now updated and regulated by SAE International.
- Flatware Grades: Another system to organize stainless steel grades in the foodservice industry is the flatware grading system. This system uses ratios such as 18/0, 18/8, and 18/10 to describe the levels of nickel and chromium in food grade stainless steel. Chromium and nickel are the two most important elements for flatware, as they affect the corrosion resistance, shine, and magnetism of the steel. Another ratio you may come across is 13/0, which is used to make most food grade stainless steel dinner and dessert knives. 13/0 stainless steel is softer than the other stainless steel grades, so manufacturers can add serration to the blade. And, while this grading system is typically used to describe flatware, it may also be used to describe some pots, pans, and other types of food grade stainless steel cookware.
What are the Major Types of Stainless Steel?
There are over 150 varieties of stainless steel, and each of them have different properties, which is why it's important to understand their variations. In the restaurant industry, it’s also especially important to distinguish between the various types because one type of food grade stainless steel may be better suited for a particular task. For example, if you’re shopping for cookware that’s going to come in contact with very salty foods, a pot made with 316 stainless steel is probably better than 304 because of its superior corrosion resistance. Understanding the differences between food grade stainless steel grades and types can help make sure that you make informed decisions and purchase the best products to suit your needs.
200 Series Stainless Steel
Stainless steel in the 200 series is lower quality and less corrosion resistant than other types. It still has its place in a commercial kitchen thanks to its affordability.
Best Applications: Food storage containers
304 Series Stainless Steel
304 stainless steel is the most common type used in the kitchen. It has a bright shine due to a high level of chromium and nickel. It's also very resistant to corrosion and rust, although it's susceptible to corrosion caused by exposure to salt.
Best Applications: Kitchen appliances, internal parts, kitchen utensils, smallwares, flatware, prep tables
316 Series Stainless Steel
This is the second most common type of stainless steel, and its alloy includes an additional element, molybdenum, which increases its resistance to corrosion caused by salt and other chemicals.
Best Applications: Kitchen equipment, hibachi grills, high-end cookware, equipment and furniture used outdoors, outdoor equipment used near the ocean
430 Series Stainless Steel
430 stainless steel contains a very small amount of nickel, and it's not as corrosion resistant as the 300 series steels. This type is also magnetic.
Best Applications: Medium-quality flatware, prep tables, appliance doors, induction-ready cookware
440 Series Stainless Steel
With a high level of carbon, 440 stainless steel is one of the strongest types used in the kitchen. Products made out of 440 stainless steel are hard, corrosion resistant, and can stand up to wear and tear very well.
Best Applications: High-quality chef knives, cutlery, oven door handles, internal parts
Flatware Stainless Steel Grades
13/0 Stainless Steel
13/0 stainless steel is used to make knives. Because this steel contains less chromium and no nickel, it's softer, allowing manufacturers to add serration to the edge.
Best Applications: Fine dining restaurants, casual eateries, hotels, and banquet halls
18/0 Stainless Steel
18/0 stainless steel is a medium-quality option, and it's one of the most affordable choices. It's not as corrosion resistant as higher flatware grades, but it's magnetic. Because it's magnetic, it can get caught by magnets in conveyor dishwashers and trash bins, helping to prevent it from being discarded.
Best Applications: Dining halls, cafeterias, catering companies, high-volume restaurants, retirement homes, casual restaurants, diners
18/8 Stainless Steel
18/8 is one of the most common types of flatware. This stainless steel has a hefty, professional feeling, and it's very corrosion resistant. Pieces made from this stainless steel usually have some sort of decoration or design.
Best Applications: Casual restaurants, upscale establishments, hotels, catering companies, banquet halls, bistros, cafes
18/10 Stainless Steel
This is the highest-quality flatware you can get. 18/10 offers superior corrosion resistance. Additionally, this flatware usually has unique and interesting designs or engravings on the handles.
Best Applications: Upscale restaurants, bistros, hotels, banquet halls, catering companies, country clubs
Stainless steel is an incredibly useful material in the foodservice industry due to its strength, durability, and corrosion resistance. Among food grade stainless steel there are a variety of types, and knowing their different properties and uses can help you make an informed purchase.