Stainless Steel Facts
What is Stainless Steel
Stainless Steel is a metal alloy made up by mixing steel with other elements to make it corrosion resistant. Iron mixed with Carbon is used to produce the steel then chromium, nickel, molybdenum, silicon, aluminium are all added in various percentages. Chromium is the main element used to help make it corrosion resistant.
After running www.allthingsstainless.com.au for over 10 years we have discovered that there are a lot of miss conceptions of Stainless Steel. Some of the most common questions we are asked are:
Will Stainless Steel Rust? Stainless steel will not rust like a car where the metal flakes out and leaves a hole. The chemicals added to the steel will eliminate this from happening. Stainless Steel can however Tea Stain if the correct grade and finish are not used for a particular application. The higher the grade and the shinier the finish the longer it will last and stay looking new. We recommend using a mirror finish in a marine environment or around swimming pools.
Is Stainless Steel Chrome Plated? No. it is a chemical mix of metals. It is then polished to a mirror or chrome like finish.
Is Stainless Steel just a coating over mild steel? No. Stainless steel is a solid material. If you drill through it you will find the same metal all the way through.
Is Stainless Steel Magnetic? Yes and no. A very obscure answer. As a general rule higher grades of stainless are not magnetic however if they are worked for example folded (bent) or heated to a high enough temperature the molecules are changed and it can become magnetic.
I thought all Stainless Was shiny? This is often asked when we sell bar products as they are only produced in a mill finish. Stainless Steel starts out as a dull grey metal and is polished to the shiny or brushed finish everyone is familiar with.
If you are in close proximity to a marine environment or a swimming pool we recommend either using 316 or 2205 stainless in a mirror finish.
Stainless Steel Grades
Although there are many grades of stainless steel available. There are only 3 common grades used when installing glass products.
Grade '304' is a general purpose stainless and is the most common grade of stainless produced. It is made up of at least 18% chromium and 8% nickel offering good corrosion resistance. 304 stainless steel is best suited for indoor use and is inadequate for many marine applications.
Grade '316' offers the best corrosion resistance among standard stainless steel and is often referred to as "marine grade". 316 stainless is made up of at least 16% chromium and 10% nickel. 2% molybdenum is also added to 316 stainless to increase its corrosion resistance. Grade 316 is most suited to outdoor and marine applications.
Grade 2205 Duplex is the newest grade we have seen come on the market. It has a very high resistance to corrosion. 2205 Duplex stainless is made up of at least 22% chromium and 5% nickel, 3% molybdenum is also added. 2205 Stainless has a higher strength than 316 and 304 grades so is often used in a marine environment where strength is important.
Stainless Steel Finishes
Although there are many different finishes available we only supply two finishes.
A mirror finish is when the stainless is polished to a finish that is brigh in colour and shows a reflection. A mirror finish is achieved by polishing up to 600grit or above. A very high mirror finish is achieved by polishing up to 2000 grit.
Satin
A Satin finish is a dull finish where if you look closely you will often see fine scratch lines around the stainless. It is achieved by stopping the polishing process at 240 grit.
How is stainless steel polished/finished?
Stainless Steel is polished by using a series of tools and materials that manipulate the surface similar to sanding a piece of timber. You start by making harsh scratches and slowly make the scratches finer and finer. The process involves sanding then buffing while slowly decreasing the harshness of the material being used.
Polishing stainless steel requires specialised tools and skills. It is not usually a task taken on by the home handyman.
Below is a good example of the polising steps required to achieve a mirror finish.