What is stainless steel?
Stainless steel is present in everyone’s daily life. It is an alloy of iron, chromium and may also contain nickel, molybdenum and other elements that have superior physical and chemical properties to ordinary steels. Its main characteristic is its high resistance to atmospheric oxidation. The main families of stainless steel, classified according to their microstructure, are: ferritic, austenitic, martensitic, precipitation-hardenable and duplex.
What makes steel stainless?
Stainless steel alloys, particularly chromium, provide excellent corrosion resistance compared to carbon steels. They are in fact oxidizable steels, i.e. the chromium present in the alloys oxidizes in contact with the oxygen in the air, forming an outer film. This very thin and stable film of chromium oxide is called a passive layer. Its function is to protect the steel surface against corrosive processes.
For this, a minimum amount of chromium is required. This film is adherent and impermeable, isolating the metal beneath it from the aggressive environment. Care must therefore be taken not to reduce the chromium content of the stainless steel locally during processing. This process is known in metallurgy as passivation. Because it is very thin, the film has little interaction with light and allows the material to continue to show its characteristic shine.
What are the applications of drawn stainless steel?
Drawn stainless steel has numerous applications. It can be used in jewelry, household appliances, electronics and telecommunications. It can also be used in leisure, fishing, nautical and railway areas. It is also used for structural purposes, conveyor belts, household utensils, fittings, car ornaments, transport equipment, car hubcaps, post fixing fittings (clamps and fasteners), structural assemblies that require high resistance, aircraft, trucks and car bodies.
It is also used in the structural part of buses, trains (almost always in the form of rectangular and square tubes), windshield wipers, safety shoes, springs, sinks, tubs, friezes, boilermaking, stamping in general and deep drawing, etc. Fun fact: the subway cars in many cities around the world are made from this material.
Why should I choose stainless steel?
Among the many advantages are:
- High resistance to corrosion;
- Adequate mechanical resistance;
- Ease of cleaning (appearing totally hygienic);
- Easy forming;
- Resistance to high and low temperatures and sudden variations;
- Varied surface finishes and formats;
- Strong visual appeal (modernity, lightness and prestige);
- Excellent cost-benefit ratio;
- Low maintenance costs.
How should stainless steel materials be cleaned?
Stainless steel materials should be cleaned with soap and detergents (mild or neutral) and ammonia solutions (homemade removers) in warm water, applied with a soft cloth or fine nylon sponge. Rinse with plenty of water and dry with a soft cloth.
What does the letter L mean after the stainless steel grade?
The use of the letter L after the stainless steel grade (e.g. 304L) means that the carbon content in the alloy is restricted to a MAXIMUM of 0.03% (normal carbon levels are 0.08% max. and in some alloys can reach 0.15% max.). This lower carbon level is used when the material is to be welded.
The lower carbon content helps prevent chromium precipitation (forming chromium carbides in the weld region) and therefore ensures a minimum of 10.5% chromium and the possibility of forming the passive film that gives stainless steel its corrosion resistance.
Why are stainless steels heat-treated?
Stainless steels used for cutting operations, where it is important to have superior surface hardness, undergo heat treatment operations. This is the case with martensitic stainless steels used to make knives, scissors, pocket knives, etc.
Is stainless steel magnetic?
There are several types of stainless steel. The 300 series stainless steels (austenitic) which contain chromium and nickel in their chemical composition are not magnetic, but can become so with any mechanical work. For example: machining, bending, rolling and drawing, due to the chemical balance in the steel melting process. Stainless steels in the 400 series (ferritic) and martensitic, which contain only chromium in their chemical composition, are magnetic.
How is brushed stainless steel made?
The brushed finish of stainless steel is obtained by sanding the surface of the steel with sandpaper or wheels of different grain sizes.
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