A high-alloy steel that can resist corrosion in the air or in chemically corrosive media,Stainless steel has beautiful appearance and good corrosion resistance. It does not need to undergo surface treatment such as color plating, and exerts the inherent surface properties of stainless steel. It is used in many A type of steel, commonly referred to as stainless steel.
The representative properties are high-alloy steel such as 13-chromium steel and 18-chromium-nickel steel.
From the metallographic point of view, because stainless steel contains chromium, a very thin chromium film is formed on the surface.
In order to maintain the inherent corrosion resistance of stainless steel, the steel must contain more than 12% chromium.
304 is a general-purpose stainless steel that is widely used to make equipment and parts that require good overall performance (corrosion resistance and formability).
301 stainless steel exhibits obvious work hardening phenomenon during deformation, and is used in various occasions requiring higher strength.
302 stainless steel is essentially a variant of 304 stainless steel with higher carbon content, which can obtain higher strength by cold rolling.
302B is a stainless steel with high silicon content, which has high resistance to high temperature oxidation.
303 and 303Se are free-cutting stainless steels containing sulfur and selenium, respectively, and are used in applications where free-cutting and high surface finish are mainly required. 303Se stainless steel is also used to make parts that require hot upsetting, because under these conditions, this stainless steel has good hot workability.
304L is a lower carbon variant of 304 stainless steel used where welding is required. The lower carbon content minimizes carbide precipitation in the heat-affected zone near the weld, which can lead to intergranular corrosion (weld erosion) of stainless steel in some environments.
304N is a nitrogen-containing stainless steel, and nitrogen is added to improve the strength of the steel.
305 and 384 stainless steels contain high nickel and have a low work hardening rate, making them suitable for applications requiring high cold formability.
308 stainless steel is used to make electrodes.
The nickel and chromium contents of 309, 310, 314 and 330 stainless steel are relatively high, in order to improve the oxidation resistance and creep strength of steel at high temperature. 30S5 and 310S are variants of 309 and 310 stainless steel, the only difference being that the carbon content is lower, in order to minimize the precipitation of carbides near the weld. 330 stainless steel has a particularly high resistance to carburization and thermal shock resistance.
Types 316 and 317 stainless steels contain aluminum and are therefore significantly more resistant to pitting corrosion than 304 stainless steels in marine and chemical industry environments. Among them, the variants of type 316 stainless steel include low-carbon stainless steel 316L, nitrogen-containing high-strength stainless steel 316N, and free-cutting stainless steel 316F with high sulfur content.
321, 347 and 348 are stainless steel stabilized with titanium, niobium plus tantalum and niobium respectively, suitable for welding components used at high temperatures. 348 is a kind of stainless steel suitable for the nuclear power industry, which has certain restrictions on the combined amount of tantalum and diamond.
