Corrosion resistance of various stainless steel materials

　　304 is a general-purpose stainless steel, which is widely used in the production of equipment and parts that require good overall performance (corrosion resistance and formability).

　　301 stainless steel shows 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 a higher carbon content, which can be cold-rolled to obtain higher strength.

　　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 occasions that mainly require easy cutting and high gloss. 303Se stainless steel is also used to make parts that require hot heading, because under such conditions, this stainless steel has good hot workability.

　　304L is a variant of 304 stainless steel with a lower carbon content and is used where welding is required. The lower carbon content minimizes the precipitation of carbides in the heat-affected zone near the weld, which can lead to intergranular corrosion (weld attack) in stainless steels in some environments.

　　304N is a nitrogen-containing stainless steel, and nitrogen is added to increase the strength of the steel.

　　305 and 384 stainless steel contain high nickel content and low work hardening rate, so they are suitable for various occasions that require high cold formability.

　　308 stainless steel is used to make welding rods.

　　The content of nickel and chromium in 309, 310, 314 and 330 stainless steel is 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 difference is 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.

　　Type 316 and Type 317 stainless steel contain aluminum, so their resistance to pitting corrosion in marine and chemical industrial environments is much better than that of Type 304 stainless steel. Among them, the variants of 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 steels stabilized with titanium, niobium plus tantalum, and niobium respectively, and are suitable for welding components used at high temperatures. 348 is a stainless steel suitable for the nuclear power industry, which has certain restrictions on the combined amount of tantalum and cobalt.