Stainless steel refers to any type of steel that contains more than 10.5% of chromium content. It can also be identified by its passive layer, which is where the oxygen chromium has formed a sealed, fixed-adhering chromic oxide layer.
Stainless steel differs to aluminium, and has several benefits, which is what makes it such a popular choice in applications across a range of industries:
- High strength: It retains its strength in a range of high and low temperatures.
- Aesthetically pleasing: Despite being extremely functional, stainless steel also looks classic, yet contemporary.
- Resistant to corrosion: It’s resistant to both water stains and rust, in a variety of pressures and temperatures.
- Easy to clean: As it’s so easy to sterilise, it doesn’t support the growth of bacteria, making it one of the most hygienic materials around.
- Recyclable: Up to 90% of stainless steel is made from recycled steel, and its qualities don’t deteriorate during the recycling process.
What is the most common stainless steel?
There are numerous variations of stainless steel, with each formulation boasting its own unique properties in terms of corrosion resistance, tensile strength, oxidation resistance, and melting point.
Despite this wide range, they can all be categorised into these three broad types:
Austenitic: Compared to other steel alloys, these have a higher chromium content, which makes them extra resistant to corrosion. They’re also not magnetic – although this can change after cold working.
Ferritic: Unlike austenitic stainless steel, ferritic ones are magnetic, and can be hardened through cold working. Because they have reduced nickel content, they also tend to be cheaper.
Martensitic: This is the least common category, and despite their high hardness, they tend to have lower levels of resistance to corrosion. For this reason, they are often used for applications that require high impact resistance and tensile strength.