Martensitic stainless steel, which can adjust its mechanical properties by heat treatment, is a kind of hardened stainless steel. The typical brand is Cr13, such as 2Cr13, 3Cr13, 4Cr13 and so on. After quenching, the hardness is high and the tempering temperature has different combination of strength and toughness. It is mainly used for steam turbine blades, tableware and surgical instruments. According to the difference of chemical composition, maraging stainless steel can be divided into two categories: martensite chromium steel and maraging chromium- nickel steel.
(1) Maraging chromium steel. In addition to chromium, the steel also contains a certain amount of carbon. Chromium content determines the corrosion resistance of steel. The higher the carbon content, the higher the strength, hardness and wear resistance. The normal microstructure of this kind of steel is martensite, and some also contain a small amount of Austenite, Ferrite or pearlite. It is mainly used to manufacture parts, components, tools and tools that require high strength and hardness, but not high corrosion resistance.
(2) Martensite chromium-nickel steel. Including maraging hardened stainless steel, semi-Austenite precipitation hardened stainless steel and maraging stainless steel, all of them are high strength or ultra-high strength stainless steel. This kind of steel has a low carbon content (less than 0.10%) and contains nickel, and some grades also contain high Mo, copper and other elements, so this kind of steel has the combination of strength and toughness and corrosion resistance at the same time. The weldability of maraging chromium steel is better than that of maraging chromium steel.