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Stainless steel is an chromium-iron alloy containing 12-30% chromium, up to 30% nickel or 24% manganese, and some amounts of molybdenum, silicon, copper, titanium, niobium, nitrogen, and the like (in quantities of not more than several percent). Chromium ensures passivity of these alloys and is therefore a crucial element needed to achieve corrosion resistance. Stainless steel in some environments is prone to local forms of corrosion (pitting, crevice, intercrystalline, and cracking corrosion). However, these problems can be avoided by the proper selection of steel for the given conditions.



Although chromium, nickel, manganese, and other alloying elements are present in relatively large quantities in stainless steels, the essential element is still iron and its carbon alloy, i.e. steel.



AISI – American Iron and Steel Institute standard for steel track. The first digit or first 2 digits in these numbers indicate the type of steel (e.g. stainless steel with high carbon content, with a low carbon content, high alloy, etc.)



AISI 304 – is an Austenitic chromium-nickel steel Authentic, and is the most widely used type of corrosion-resistant material, providing very good resistance to corrosion, with cold resistance and good weldability. It is resistant to water, steam, humidity, edible acids, weak organic and inorganic acids. Forged stainless steel at least 6-mm thick is resistant to intercrystalline corrosion, even without additional heat treatment (low carbon content). It is approved for thermal stress of up to 300 °C; while for higher working temperatures, titanium-stabilized Steel AISI 321 should be used. This steel has good polishing qualities, is ductile, and has excellent tensile, bending and rolling characteristics. In the machining sector, thanks to its ability to do more work, it used for sharp instruments made from high-alloyed high-speed steel, hard metal or carbide alloys. It is suitable for all types of electric arc welding, but not suitable for flame welding. It is used in the engineering and the nuclear industry, architecture, transport facilities, the food industry, in the pharmaceutical and cosmetic industry, in the construction of chemical apparatus and motor vehicles, the production of surgical instruments, sanitary equipment, household tools and appliances and artistic objects.



AISI 316L– is an Austenitic acid-chromium-nickel molybdenum steel with carbon content of up to 0.03%. This steel is highly resistant against corrosion and acids, with a slight tendency to pitting corrosion in solutions containing chlorine. The steel has very good weldability, without the need for additional heat treatment for welding, with a high intercrystalline corrosion resistance, high-gloss polishability; and it is also extremely ductile (good bending, rolling, high tensile, stamping, etc. properties). Usage: components, instruments and equipment for the chemical sector with high chemical stresses (the presence of chlorides), in the production of hot water treatment facilities and components that come into contact with seawater.



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