Stainless/ rust solid steel is a generic term for steel typescontaining more than 12% chromium. The addition of other alloy elements, nickel, molybdenum, carbon, nitrogen, manganese, silicon,titanium, etc., has developed a large number of steel types, each of which is characterised by certain properties in terms of corrosion resistance,mechanical strength, weldability and malleability.
The chromium content causes the steels to form a very thin passive oxide film, which makes the steels have good resistance in a neutral oxygen-containing environment. On the other hand, most stainless/rust-resistant steels are not resistant to acid and seawater, and usually not salt.
The steels are usually broken down according to the microstructure, which determines the mechanical properties. The following main types are distinguished:
Ferritic stainless/rustproof steel. The simplest and cheapest stainless steel types. Has mechanical properties reminiscent of unalloyed/low alloy steel. Typically chosen where you want good corrosion resistance at reasonable price. For example, AISI 430 and 440.
Martensitic stainless/rustproof steel. Related to the ferritic stainless steel types, only with higher carbon content, which makes it possible to harden the steel. Can be hardened and possibly called to very high hardness and reasonable toughness. Often used where corrosion resistance and wear resistance are important, such as knives and other cutting tools. For example, AISI 410 and 420.
Ferritic- austenitic stainless steel (Duplex steel). Duplex The steels have a mixed structure consisting of ferrite and austenite (approx. 50/50). In general, duplex steels have higher strength than both ferritic and austenitic steels, as well as excellent toughness. Have excellent fatigue strength due to the mixing structure (do not become easily metal board). Like the austenitic steels, they are weldable.