It is because of the chromium that stainless steel does not easily corrode, rust or stain like mild steel does, although it is not fully stain-proof, particularly in adverse conditions such as salt or lack of air.
Stainless steel is ideal in environments which need both a resistance to corrosion and the properties of steel, as well as for its aesthetic appearance.
Properties of Stainless Steel
Unlike mild steel which rusts readily when exposed to air and moisture, the chromium in stainless steel forms a corrosion-resistant and invisible chromium oxide film. This film is resistant to water and air and therefore prevents corrosion both on and beneath the surface. It is also lustrous and tough, and if the film is scratched or damaged it reforms quickly in oxygen, thus repairing itself (called passivation).
There are more than 60 grades or specifications of stainless steel and surface finishes which makes it suitable for a wide range of different environments so it’s important to know which grade to use for a particular purpose.
As the grade changes, so does the workability of the material. Grade 304 is the most versatile and most widely used stainless specification, available in a wider range of forms and finishes than any other. It is ideal for fabrication and welding, and it is the grade we work with at Dymond.
Mill finishes offer the cheapest finish option. The finish varies from dull to mirror-like and becomes less uniform as the thickness or diameter of the steel increases.
Brushed Stainless – 240 grit
A brushed finish is created using bristles or nylon fabric in a fine abrasive action which does not remove the surface layer. This creates what’s referred to as grit and there are a number of GRIT specifications. ‘240 grit polished’ is the finish we work mostly with at Dymond.
A polished finish is produced either mechanically using a series of gradually finer abrasives, or by a rolling procedure that simulates the appearance of mechanical abrasion. To achieve an even smoother polish, the polished surface is further buffed to give a mirror-like appearance which is referred to as ‘mirror polished’.
These include random scratch patterns, swirls, circles, embossed textures, and various colouring and coating methods. They tend to be used when the appearance is important and for specialised industrial purposes.
Fabrication of Stainless Steel
Benefits of Stainless Steel
Hygiene – easy to clean, without harsh products
Aesthetic appearance – bright, attractive and easy to maintain
Impact resistance – very tough
Fire and heat resistance
Long term value
cost-effective – long lasting without the need for further protection Sustainability – environmentally friendly due to the above benefits.
Uses of Stainless Steel
Stainless steel’s resistance to corrosion and staining, its attractive appearance and its lack of maintenance make it ideal for many applications.
Typical applications include:
- Food processing equipment, brewing
- Kitchen hardware and appliances
- Industrial equipment
- Catering equipment
- Hospital equipment
- Shop fittings and retail display equipment
- Chemical containers,
- Heat Exchangers
- Firearms and handguns
Stainless steel is environmentally friendly. It is 100% recyclable, with an average of 60% recycled material of which about 40% comes from recycled products and 60% from the manufacturing processes.
It’s long-lasting and corrosion resistant qualities leads to a reduction in the use of resources, maintenance and harsh cleaning products.