Steel is an alloy of iron and carbon. Stainless steel, specifically, contains at least 10.5% chromium and less than 1.2% carbon and other alloying elements. Chromium is the element that prevents the iron from rusting and provides heat-resistant properties.
Stainless steel is an alloy of iron and carbon. It contains other elements including chromium and nickel. Different percentages of the elements give it different properties. For example, the more chromium stainless steel contains, the more resistant it is to corrosion.
Stainless steel can rust. The extent of the rusting depends on the level of chromium in the alloy – the more chromium, the more resistant stainless steel is to rusting. Rusting usually happens when a corrosive substance damages the chromium oxide layer that forms on the outside of stainless steel. Corrosive substances include humid air, salt water, and some cleaners and chemical liquids.
Stainless steel retains its integrity for over 50 years. The metal can take 100 to 1,000 years to completely breakdown into natural elements.
Stainless steel can be easily maintained with warm water and soap or a mild detergent. Make sure to use a cloth or soft sponge when cleaning, as scratches on the external chromium oxide layer can lead to tarnishing and rusting.
Stainless steel should not tarnish or turn green if the chromium content is more than 12%. An increased oxidisation of stainless steel due to moisture, salty water or wear and tear can lead to a more prevalent chromium oxide layer, which is green of colour.
Grades 410, 420, and 440 of stainless steel contain large quantities of ferrite – a blend of iron and other elements which has magnetic qualities. This makes them magnetic.
Stainless steels that contain austenite – collectively called austenitic stainless steels – are non-magnetic. Austenitic stainless steels have a crystalline structure, and contain iron, carbon, chromium, nickel, and small amounts of other elements.
Grade 316 is commonly referred to as the food grade stainless steel. Food grade stainless steel is resistant to wear and tear and offers a level of heat resistance that makes it suitable for using on stoves. Other grades that offer these properties and are therefore suitable for food environments include 430 and 304.
Stainless steel does tarnish – eventually. Stainless steel tarnishes a lot slower than other metals because it contains chromium, which prevents the iron from tarnishing and rusting. The higher the chromium level, the more resistant stainless steel is to tarnishing.
Stainless steel is typically used in:
- Civil engineering
- Catering environments
- Land and offshore industrial environments
- Chemical industry
- Medical industry
Stainless steel is 100% recyclable, although can’t be disposed of in household rubbish collections. Instead, take it to your local waste processing centre, where metals are put into a skip and then taken off to be recycled.
Stainless steel can be welded. One of the easiest ways and cheapest ways to weld stainless steel is using the MMA (manual metal arc) welding method. As long as you have a welding machine with stick welding capability, you’ll just need suitable rods and the right electrode. Thicker stainless steel is generally easier to weld than thin stainless steel.