Understanding Grades of Stainless Steel

Stainless steel can come in many different grades, which affect attributes such as corrosion resistance, tensile strength, hardness etc.

Hardness is shown after the grade in Stainless products - such as A4-50, A4-70 and A4-80. The different hardness' are shown respectively

  • -50: Regular Grade

  • -70: Hardened

  • -80: Highly Hardened

Below are some of the main grades of stainless steel with their attributes explained

Most of our fasteners on our online shop are -70 grade hardness by standard unless stated otherwise.

A1 Grade

A1 stainless steel has added sulfur for added ease of manufacture, leading to decreased prices. However, this leads to increased susceptibility to corrosion compared to other grades of stainless steel.

A2 Grade

This grade of stainless steel, known to some as 'commercial grade' stainless steel, is often used in the food industry due to its resistance to corrosion by foodstuffs, sterilising chemicals, etc.

A4 Grade

'Marine Grade' Stainless Steel is a grade of stainless steel even higher than that of A2 Grade, due to the addition of molybdenum, enabling it to be used in extremely corrosive environments, such as the sea.

A5 Grade

This grade of stainless steel is similar to A4 grade of stainless steel, however, it offers extra stability - as it is stabilised with titanium.

Contact Us for specialist advice on what to use