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What Do the Material EN Numbers Mean?

Published by Rapid Metals on

Rapid Metals is a leading supplier of engineering steel, among other types of metals for commercial and hobbyist use. We strive to make the online ordering process of metals, particularly engineering steel, as easy as possible. To do this, we separate our engineering steel range by EN numbers. This makes it easier for clients to navigate directly to what they need – if they know what EN numbers are. 

For those who are new to metalwork or who are not familiar with EN numbers for engineering steel, it can be bewildering to know what each EN number means and which one is needed for the project at hand. To help you figure out exactly what you need and better understand what EN numbers are in relation to engineering steel, we’ve put together this handy guide as to what material EN numbers mean. 

What is an EN number?

EN stands for emergency number and is a European standard, though it was originally created by the British. EN numbers are used as a way to identify the specification, grade, and chemical components of metals; most commonly steels. The system was first introduced in 1941 to make it easier to create class standards of products being produced in Word War II. 

Confusingly, there are other types of classifications you may come across. BS refers to British standards which are only recognised in Britain. BS EN refers to British standards derived from European standards (original ENs) that are recognised in both Britain and Europe. 

What is the EN number formula? 

EN numbers can be split into sections. First, an EN number is followed by a number. The number that directly follows the letters EN refers to the quality of the steel and the amount of carbon or other blended elements. The EN classifications are as follows:

EN1 – EN3: this refers to steel that has a low carbon content. Steels labelled EN1 – EN3 are considered general purpose steels and are commonly used for things like handles, casings, and other low-stress applications.

EN5 – EN16: this refers to steel that has a medium carbon content. Steels labelled EN5 – EN16 are considered general purpose strength steels and are commonly used for things like screws, bolts, and other mild-stress applications. 

EN19 – EN24: this refers to steel that has a high carbon content. Steels labelled EN19 – EN24 are considered hard steels with high strength and are commonly used for things like engine gear boxes and other high-loading applications. 

EN32 – EN36: this refers to steel that has a high carbon content. Steels labelled EN32 – EN36 are considered hard steels and are commonly used for things like spindles, gears, and other low-tensile applications.

EN40 – EN45: this refers to spring steel that has a high carbon content. Steels labelled EN40 – EN45 are known for their flexibility without becoming deformed, meaning they are commonly used for things like saw blades, springs, and historically, swords.

EN56 – EN60: this refers to stainless steel that is made primarily from iron and carbon, though other alloying elements like chromium are also added. Stainless steel is most commonly used for things like sinks, cutlery, kitchen appliances, and other high-durability applications. 

Type of Steel

The next part of an EN number formula is three numbers that refer to the type of steel. This number is usually within a bracket, e.g. EN3 (070…). The number refers to the type of steel. Common classifications include:

000 – 199: this refers to manganese steel. The number refers to the manganese content x100.

200 – 240: this refers to free-cutting steel, with the last two numbers referring to the sulphur content x100.

250: this refers to silicon manganese steel. 

300 – 499: this refers to stainless and heat-resistant steel.

500 – 999: this refers to alloyed steel. 


Following the number, there will be a letter, for example, EN3 (070m…). This refers to the specification of the steel. There are four letters that are commonly used:

A: this refers to steel that has a chemical composition.

H: this refers to ‘hardenable’ steel. 

M: this refers to steel that has specific mechanical properties. 

S: this refers to stainless steel. 

Carbon Content

The final section of an EN number relates to the carbon content of the steel x100, for example, EN3 (070m20). 

Grades of Engineering Steel

At Rapid Metals, we supply a wide range of engineering steel, including EN1a, EN8, EN24t, and EN19t. If you’re still unsure what the EN numbers mean or what grade you need, please contact us. A member of our team will be happy to advise you further. Alternatively, place an order online for nationwide delivery across the UK. 

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