Most people are unsure whether stainless steel is a magnetic or non-magnetic metal. Some believe it is magnetic because it contains trace amounts of iron, but in reality the answer is neither yes nor no. Some types of stainless steel are magnetic, others are not.
What makes stainless steel magnetic?
To make stainless steel magnetic, it must meet certain requirements:
· The alloy must contain iron.
· The crystal structure of the alloy must be arranged in a martensitic or ferritic structure.
All stainless steel metals are a type of steel. This means that their chemical composition contains iron. In most cases, stainless steel variants with iron in their composition are magnetic. If the alloy has an austenitic crystal structure, it is not magnetic.
What types of stainless steel are magnetic?
Regardless of speciesstainless steelis magnetic or not, it can be grouped depending on the type of stainless steel. Some of the typical magnetic stainless steels are:
· Stainless steels409,430and 439 also known as ferritic stainless steel.
· Stainless steel grades 410, 420 and 440 – martensitic stainless steel.
Austenitic stainless steel
Most stainless steels that fall into this category are non-magnetic because they contain large amounts of austenite. Although some metals, such as grades 304 and 316, have iron in their chemical composition, they are austenite, meaning they are non-ferromagnetic.
They can be made partially magnetic by a special heat treatment or hardening, which can cause ferrite to form in some places. This is why austenitic grades vary slightly in magnetism on any edge that has been mechanically worked, such as the edge of a plate.
Why is magnetism in stainless steel important?
Magnetism affects the performance and intended use of the material during application. Due to manufacturing and other processes such as welding, magnetic materials can complicate the processes performed. Magnetic materials can also cause electric currents to behave differently.
