What are the different steel grades and what do they mean?

22 January 2019

When it comes to understanding the different types of steel available, things can get very complicated, very quickly.

But don’t worry.

For the vast majority of situations, you can actually keep things pretty simple.

In fact, here at Fussey Engineering, we predominately use only two different types of mild steel, known as S275 and S355 – we’ll explain what those codes mean in a moment.

But first, why are there so many different grades of steel?

Why are there so many steel grades?

There are four types of steel: carbon steel, alloy steel, stainless steel and tool steel.

Different steel grades simply denote the chemical make-up of that particular type of steel.

Here at Fussey Engineering, we are only concerned with carbon steel, which is made by mixing iron with different amounts of carbon.

If the steel contains a very small amount of carbon, it will be a little softer and more malleable. So, it might be perfect for making items like pipes or sinks.

Alternatively, if the steel contains a higher level of carbon, it will be stronger. Stronger steels are naturally more appropriate for structural applications, such as the skeleton of a warehouse.

Still, despite all these different grades of steel, it is necessary for standardisation in the industry. That way you know exactly what type of steel you’re getting.

The different standards

As with most things, different countries have different standards.

At the moment, we predominately work with the current European Standards (ENs), which also acknowledge the British standards.

We mentioned before the two main types of steel we use: S275 and S355.

When you see a code like this – with a letter and then a number – the letter represents what the steel is used for and the number represents its strength.

So, in the case of S275 and S355, the ‘S’ represents ‘structural steel’ and the 275 and 355 represent different strengths.

For the vast majority of the work we carry out, either one of these two types of steel will be suitable for the job.

All our steel is tested

As well as the basic European Standards code, you may also come across two more letters combinations when considering which steel is right for a particular job.

These are the impact and temperature testing symbols.

Combinations of these symbols are numerous, but the most common you’ll see used are JR and JO.

The ‘J’ represents the strength to which the steel is tested.

The ‘R’ and ‘O’ represent the temperature it’s tested at (‘R’ is room temperature, whilst ‘O’ is zero degrees).

All of the steel we use here at Fussey Engineering is tested before use.

The right steel for the right job

Hopefully this article has given you some insight into the area, but you can see how dealing with different steel grades can soon become overwhelming.

The good news is: here at Fussey Engineering, we take all of the confusion out of it for you.

Our estimation team will analyse your particular needs and figure out the right steel grade for the job. And of course, we’ll make sure it’s all tested accordingly before use.

So, to find out which steel grade would be right for the job you’re looking to price up, just get in touch.

Click to view tables showing the grade, properties and nearest equivalent grades from earlier standards.

You can call us on 01469 540644 or email us at info@fusseyengineering.com to arrange an estimate with one of our steel experts.

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