Blog Post Stainless Steel Grades Explained

When it comes to stainless steel, you may not know that it’s not only graded, but there are a variety of grades too. Stainless steel grades are determined by their chemical composition and the purity of their alloy. But why does this matter?

The stainless-steel grade is an important quality indicator for stainless steel products. It can be used to judge whether a specific product is appropriate for a given application. For example, to illustrate this, a low-grade stainless steel will corrode faster and more easily than a high-grade stainless steel. This is why it is important to know what type of grade you are using in relation to what it will be used for.

In this article, we’re going to take a look at the various stainless steels in more detail to provide detailed information that can help you in your business.

What Defines Steel

Steel is an iron-carbon alloy with less than 2% carbon, 1% manganese, and trace amounts of silicon, phosphorus, sulphur, and oxygen. Steel is a type of metal that is widely used in construction, industrial machinery, and weapons. It is also a widely popular material for the manufacture of cans and other packaging items.

Difference Between Steel and Stainless Steel

Stainless steel is a type of steel that is resistant to corrosion and rusting. It is generally used in the manufacturing of cooking utensils, kitchenware, and other household items but also construction, offshore pipework and storage tanks for corrosive materials. The difference between stainless steel and regular steel is that stainless steel has a layer of chromium-nickel alloying it on the surface which makes it harder to corrode and rust. This layer also prevents oxidation from occurring in the metal.

Stainless Steel Identifiers: Understanding the Various Types

When it comes to understanding stainless steel, it’s important to look for the right identifiers. In short, there are two main labels to look out for. These are families and grades. But what can you discover about them based on both labels? Let’s discover more on both.

Stainless Steel Families

For starters, families tend to identify properties of the steel. They indicate differing metal ratios and fall into four main families that are Austenitic, Ferritic, Duplex and Martensitic & Precipitation Hardening stainless steel. But the family is just one way of understanding this metal, it’s essential to also look at the grade too. This will allow you to understand what differentiates the different types.


Stainless Steel Grades

Stainless steel grades are a type of classification. The grade is determined by the alloy composition, which includes a specific percentage of chromium and nickel. Stainless steel grades are typically described by their composition, which includes a specific percentage of chromium and nickel.


Different Stainless Steel Grading Systems

There are three main, commercially available, stainless steel grades: 304, 316, and 430. These grades can be further subdivided into many different types of stainless steel with different properties.

Common Stainless Steel Grades

Because of its durability and corrosion resistance, stainless steel is a popular material for kitchen and home appliances. The most common grade of Stainless Steel is 304, which is a type of austenitic stainless steel that has good corrosion resistance and is widely used for food packaging. The next most common grade is 316 which is also Austenetic. It has exceptional corrosion resistance. The third most common grade is 430, Which is a Ferritic alloy. Compared to 304/316 it has a poor corrosion resistance.

Stainless Steel: 304 Grade

304 grade stainless steel is a type of stainless steel that is designed to resist corrosion. It’s known as the benchmark grade that is suitable for the widest scope of applications. It has a high level of resistance to abrasion and stress-corrosion cracking. It is widely used in the construction industry due to its durability and resistance to corrosion. 304 grade stainless steel is also used in the automotive industry for parts like radiators, engine blocks, manifolds, exhaust systems and even exhaust pipes. Grade 304 can also be broken down further. For example, a lower carbon version of 304 (304L) is also widely used. Standard 304 has a maximum carbon content of 0.08%, whereas 304L has a max carbon content of 0.03%. In the majority of applications, you wouldn’t notice a difference but the low carbon content makes the welding process easier. The trade-off is that low carbon 304 has a slightly weaker tensile strength. It is also known as 1.4301 (304) and 1.4307(304L).

Stainless Steel Grades 304 vs 316

Stainless steel grades 304 and 316 are often interchangeable, but the subtle differences could have a huge impact and make it vital that the correct grade is used in certain environments.  

Grade 304 is less carbon-rich than grade 316 and is more ductile. It is also softer than grade 316, which makes it easier to form a good weld joint. This makes it ideal for applications such as food processing equipment, dairy equipment, dishwashing machines, coffee machines, and so. Grade 316 has a higher Nickel content and also molybdenum, which is why its corrosion resistance is superior to 304. This, however, makes grade 316 40% more expensive than 304.

Stainless Steel: 316 Grade

316 grade stainless steel is one of the most widely used types of stainless steel where the corrosion resistance of 304 isn’t adequate. Offshore, chemical processing, medical equipment and marine parts are all industries that would use 316 due to the highly corrosive environments. It is visually identical to grade 304. It is also known as 1.4401(316) and 1.4404(316L).

Stainless Steel: 430 Grade

430 grade is a Ferritic grade. It has no Nickel in it which makes it far less corrosion resistant than grade 304 but also considerably less expensive. This grade is often used where cost is more important than the life expectancy of the application. Being a Ferritic grade, 430 is highly magnetic where 304/316 have a very low magnetic field. Its main uses are in domestic appliances and decorative trims.

If you need more information about the best type of stainless steel for your product, feel free to contact our professional team at Leengate Metals for assistance based on the features and requirements of your project.