Steel Fabrication Guide: Explaining Steel Grades

What are Steel Grades?

Steel grading systems exist to categorize different types of steel based on their various factors. It surprises some people that there isn’t just one type of steel; steel is a material that can be used in countless other ways, but that’s only because of the possible combinations of elements that create the alloy. 

The customisation available means that there are over 3500 different grades of steel, all of which have their advantages during steel fabrication. The steel grade is decided by the amount of carbon it contains, any other alloys it contains, and how it’s processed.

Before we get into the specifics of the different grades, let’s look at an overview of the variety of steel available.

What are the Different Types of Steel?

The massive variety of steel grades available all fall under one of four categories, each of which is made using different processes and elements. Take a look at the list below to learn more:

• Carbon Steels - The easiest way to understand this group of steels is to see them as the purest forms of steel. All of the steel grades in this category only contain trace amounts of anything other than iron and carbon, and the wide variety of carbon steel grades account for 90% of steel production. Despite the supposed purity of this category, there is still a lot of variation in these steels. The amount of carbon used in the alloy can be adjusted, which results in a differing malleability of the material.
  
• Alloy Steels - As the group’s name suggests, these types of steel contain other alloying elements, including substances such as copper, aluminium and nickel. These are used to add strength, ductility, corrosion resistance and more to the steel, providing endless opportunities for steel fabrication.
  
• Stainless Steels - This steel grade group contains between 10-20% chromium as their alloying element and is commonly used in many different areas whenever corrosion resistance is the priority. Everyday products made through stainless steel fabrication include cutting tools, food processing equipment and medical equipment. 
• Tool Steels - Tools require different material characteristics than household items, and therefore this category of steel grades are made from elements that add strength and durability. Usually produced by adding materials such as tungsten and cobalt (among others), tool steels make excellent cutting and drilling equipment and provide exceptional heat resistance.

Once you know which group is suitable for your project, you can look at the various steel grades available and choose the exact type to use during steel fabrication.

Understanding the Steel Grading System

The four different types of steel explained above encompass the thousands of unique steels available to be used, so the grading system is used to provide some order and explain the subtle differences between each variation.

Slight differences in the added elements added to steel and the rates with which it’s heated and cooled can create a different chemical makeup, resulting in differing advantages. This standardisation is vital to ensuring that a suitable steel grade is used in every project.

For example, when looking at steel fabrication, common grades of carbon steels used are S275 and S355. When you see codes like these which consist of a letter and then a number, the letter indicates what the steel is used for, and the number represents its strength. So, in the case of S275 and S355, the ‘S’ means ‘structural steel’, and the ‘275’ and ‘355’ represent different strengths.

Find Local Steel Fabrication Services

We hope that you’ve gained more understanding of the steel grading system after reading our blog post. If you have further queries, the Buy A Beam store is a great simple way of ordering steel online, which local steel fabricators in the UK will supply. If you have any questions, contact us today, and we’d be happy to help.