Composition of Stainless Steel
Steel is an alloy of iron and carbon. Stainless steels are steels containing at least 10.5% chromium, less than 1.2% carbon and other alloying elements.
Composition of Stainless Steel
 
Reaction of Steel and Stainless Steel to Contact with Air, Humidity or Water
Stainless steel’s corrosion resistance and mechanical properties can be further enhanced by adding other elements, such as nickel, molybdenum, titanium, niobium, manganese, etc.

Aperam offers a complete range of solutions. Our five categories of Stainless Steels are differentiated by the alloying elements added to iron, carbon and chromium.
Reaction of Steel and Stainless Steel in Contact with Air Humidity or Water

Stainless Steel Families

We offer a complete range of solutions with 5 categories of Stainless Steel differentiated by the alloying elements added to iron, carbon and chromium.

Austenitic S300
Austenitic S300
Austenitics or 300 series

0.015 to 0.10% carbon, 16 to 21% chromium, 6 to 26% nickel, 0 to 7% molybdenum. The presence of nickel improves corrosion resistance and makes stainless steel more ductile. The presence of molybdenum further enhances the resistance to corrosion in an acid medium. The most common grades are 304/304L and 316/316L.

Applications
Boiler market, aeronautics, electronic components, railway equipment, tubes, chemical tanks and food vats, marine applications, tanks…

Heat resistant steel applications
Heating systems, resistor jackets, furnace equipment

Austenitics with manganese or 200 series
Austenitics with manganese or 200 series
Austenitics with manganese or 200 series

These are chromium manganese steels, with a low nickel content (always below 5%).

Applications
Asphalt tankers, tubes, food containers, silos, conveyor chains, safety soles…

 
Iron
 
Austenltic Molybdenum, aluminium, copper
 
Nickel
 
Chromium
 
Carbon
 
Manganese
Ferritic S400 Solutions KARA
Ferritic S400 Solutions KARA
Ferritics or 400 series: the KARA ferritic offer

0.02 to 0.06% carbon, 10.5 to 30% chromium, 0 to 4% molybdenum. Commonly used internally, these grades are now being developed for envelope and structural products.

KARA is the Aperam brand for ferritic stainless steels. Unlike other stainless steels, the KARA range doesn’t contain nickel and is thus immune from the erratic price fluctuations of this alloying element. As a result, prices are more stable over time, giving KARA a strong argument in the construction sector where project cost and economic design are key elements.

Applications
Car exhaust systems, conveyor chains, cooking utensils, boilers domestic electrical appliances, domestic appliances, trim, dishware, heating, hot water tanks, tubes …

Kara

Austeno-ferritics or Duplex
Austeno-ferritics or Duplex
Austeno-ferritics or Duplex

0.02% carbon, 0 to 4% molybdenum, 1 to 7% nickel and 21 to 26% chromium. These stainless steels not only offer excellent quality, because of their low nickel content – a material that suffers from highly speculative prices – they are also very cost effective.

Applications
Oil, gas, papermaking pulp, desalination sectors, chemical industry…

Martensitics
Martensitics
Martensitics

0.1% carbon, 10.5 to 17% chromium. Mainly used for tooling, cutting tools and springs.

Applications
Cutlery, cutting tools, construction tools…

General Properties of Stainless Steel

Aesthetics

Aesthetics

It has a great variety of surface finishes, from matt to bright and including brushed and engraved. It can be embossed or tinted, making stainless a unique and aesthetic material. It is often used by architects for building envelope, interior design and urban furniture.
Mechanical properties

Mechanical properties

Compared to other materials, stainless steel has strong mechanical properties at ambient temperatures – it is steel after all! In particular, it combines ductility, elasticity and hardness, enabling it to be used in difficult metal forming modes (deep stamping, flat bending, extrusion…) while offering resistance to heavy wear (friction, abrasion, impact, elasticity …). Furthermore, it offers good mechanical behaviour at both low and high temperatures.
Resistance to fire

Resistance to fire

Stainless steel has the best fire resistance of all metallic materials when used in structural applications, having a critical temperature above 800°C. Stainless steel is ranked A2s1d0 for fire resistance with no toxic fume emissivity.
Corrosion resistance

Corrosion resistance

With a minimum chromium content of 10.5%, stainless steel is continuously protected by a passive layer of chromium oxide that forms naturally on the surface through the combination of chromium and moisture in the air. If the surface is scratched, it regenerates itself. This particularity give stainless steels their corrosion resistance.
Cleanability

Cleanability

Stainless steel items are easy to clean, usual cleaning products (detergents, soap powders) are sufficient and do not damage the surface.

Stainless steel fully meets requirements in fields such as decoration and cooking utensils that require frequent and effective washing.
Recycling

Recycling

Stainless steel is the “green material” par excellence and is infinitely recyclable. Within the construction sector, its actual recovery rate is close to 100%. It is environmentally neutral and inert when in contact with elements such as water and it does not leach compounds that might modify their composition.

These qualities make stainless steel ideally suited to building applications exposed to adverse weather, such as roofs, facades, rainwater recovery systems and domestic water pipes. Stainless steel’s longevity fulfils the requirements of sustainable construction, and effective election, installation and low maintenance guarantee the user unrivalled service life.

Additional advantages

- resistance to corrosion in highly corrosive environments
- resistance to oxidation and creep resistance at high temperatures
- strength and ductility at low temperatures
- good mechanical properties
- easy to work with (stamping, bending, hydroforming, welding, brazing…)

Stainless Markets

Manufacturing Process

Stage 1: The melt shop
Stage 1: The melt shop
Stage 2: Hot rolling mill
Stage 2: Hot rolling mill
Stage 3: First annealing and pickling
Stage 3: First annealing and pickling
Stage 4: Cold rolling and final annealing
Stage 4: Cold rolling and final annealing
Stage 5: Metal finishing
Stage 5: Metal finishing