Many types of stainless steel have been developed to resist different corrosive environments and working conditions ensuring that work is safe, products last longer and our food for example is hygienic.
These stainless steel grades normally have a minimum content of 10.5% chromium. Chromium makes the steel 'stainless' - this means improved corrosion resistance. Various milling and processing conditions influence the surface and mechanical properties.
Besides chromium, typical alloying elements are molybdenum, nickel and nitrogen. These elements, most of them traded on the London Metal Exchange, influence the price of the different alloys. Nickel is mostly alloyed to improve the formability and ductility of stainless steel, molybdenum influences its tensile strength and durability. Alloying these elements brings out different crystal structures, giving different properties in machining, forming, welding etc.
Below please find a description of some of the most commonly used stainless steel grades and standards.
EN 1.4301 (Austenitic)
One of the most widely used general-purpose stainless steels. It possesses an excellent combination of strength and corrosion resistance, and it is easily fabricated. To reduce carbide precipitation when welding, it is recommended to use 1.4307 for its lower-carbon content.
EN 1.4401 (Austenitic)
Superior corrosion resistance compared to other 300 series alloys when used in harsh corrosive environments (e.g sea water, chemicals, etc.). To reduce carbide precipitation when welding, it is recommended to use 1.4404 for its lower-carbon content.
EN 1.4541 (Austenitic)
Titanium stabilized stainless steel to prevent intergranular formation of chromium carbide. It exhibits strength characteristics superior to those of 1.4301 stainless, thus making it best suited for parts which cannot be subsequently annealed.
EN 1.4016 (Ferritic)
A general-purpose non heat-treatable chromium type used for highly polished trim applications in mild atmospheres. Its strengths are in ductility, formability, good corrosion and oxidation resistance, thermal conductivity and finish quality.
Ni base Alloys and Titanium
When additional heat or chemical resistance is required, the choice of nickel-based alloys or titanium may be mandatory. These alloys are characterized by an excellent resistance to corrosion, from the most oxidant acids to saline atmospheres.