Basic models of stainless steel

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Sulfur and phosphorus in stainless steel: The sulfur content in steel shall not exceed 0.05%； In general steel, the phosphorus content is limited to below 0.0%. Therefore, the sulfur and phosphorus content is a very important indicator; carbon structural steel and high-quality carbon structural steel are classified based on this: steel with sulfur and phosphorus contents of no more than 0.04% is considered high-quality steel ； Steel with a sulfur content of no more than 0.03% and a phosphorus content of no more than 0.035% is referred to as high-grade high-quality steel ； Steel with a sulfur and phosphorus content of not more than 0.025% each is referred to as steel of extra-high quality. Common stainless steel grades are denoted by numerical codes; there are the 200 series, 300 series, and 400 series – this is the classification system used in the United States. Examples include 201, 202, 302, 303, 304, 316, 410, 420, 430, etc. In China, stainless steel grades are indicated using element symbols along with numbers, such as 1Cr18Ni9, 0Cr18Ni9, 00Cr18Ni9, 1Cr17, 3Cr13, 1Cr17Mn6Ni5N, etc., with the numbers indicating the respective content of each element. 200 series: Chromium-nickel-manganese austenitic stainless steel. 300 series: Chromium-nickel austenitic stainless steel. 301: Good ductility, used for shaped products. It can also harden through machine speed. It has good weldability. Its wear resistance and fatigue strength are superior to those of 304 stainless steel. 302: Has the same corrosion resistance as 304; it offers better strength due to its relatively higher carbon content. 302B: is a stainless steel with a high silicon content, and it possesses excellent resistance to high-temperature oxidation. 303: It becomes easier to machine by adding small amounts of sulfur and phosphorus. 303Se: It is also used to manufacture components that require hot heading, as this stainless steel exhibits good hot workability under such conditions. 304: That is 18/8 stainless steel. The GB grade is 0Cr18Ni9. 309: Has better heat resistance compared to 304. 304L: It is a variant of 304 stainless steel with a lower carbon content, used in applications that require welding. The lower carbon content minimizes the precipitation of carbides in the heat-affected zone near the weld, and the precipitation of carbides can cause intergranular corrosion (weld erosion) in stainless steel under certain conditions. 304N: It is a nitrogen-containing stainless steel; nitrogen is added to enhance the strength of the steel. 305 and 384: They contain higher levels of nickel, have a low rate of work hardening, and are suitable for various applications where high cold formability is required. 308: Used for making welding electrodes. 309, 310, 314, and 330: They contain relatively high levels of nickel and chromium, which is intended to improve the steel’s oxidation resistance and creep strength at high temperatures. 30S5 and 310S are variants of 309 and 310 stainless steels; the only difference is that they have a lower carbon content, which serves to minimize the formation of carbides in the area near the weld. 330 stainless steel possesses particularly high resistance to carburization and thermal shock. 316 and 317: Containing aluminum, they have **superior pitting resistance in marine and chemical industry environments compared to 304 stainless steel. Among them, type 316 stainless steel has variants including low-carbon stainless steel 316L, high-strength nitrogen-containing stainless steel 316N, and free-cutting stainless steel 316F with a higher sulfur content. 321, 347, and 348: are stainless steels based on titanium, niobium plus tantalum, and niobium-stabilized respectively, and are suitable as welded components for use at high temperatures. 348 is a stainless steel suitable for the nuclear power industry, with certain limits on the combined content of tantalum and tungsten. 400 series: Ferritic and martensitic stainless steels. 408: Good heat resistance, low corrosion resistance; 11% Cr, 8% Ni. 409: The cheapest option (in the UK and US); typically used for car exhaust systems; it is a ferritic stainless steel (chromium steel). 410: Martensitic (high-strength chromium steel); good wear resistance, but poor corrosion resistance. 416: The addition of sulfur improved the processability of the material. 420: “Blade-grade” martensitic steel, similar to the earliest stainless steels such as Brinell high-chromium steel. It is also used in surgical knives, and can be made extremely shiny. 430: Ferritic stainless steel, used for decorative purposes, such as in automotive accessories. It has good formability; however, its temperature resistance and corrosion resistance are poor. 440: This is a high-strength tool steel with a slightly higher carbon content. After appropriate heat treatment, it can achieve a relatively high yield strength; its hardness can reach 58 HRC. It ranks among the hardest types of stainless steels. The most common example of application is “shaving blades”. There are three common types: 440A, 440B, and 440C. Additionally, there is 440F (a type that is easy to machine). Series 500: heat-resistant chromium alloy steel. Series 600: martensitic precipitation-hardening stainless steel. 630: the most commonly used precipitation-hardening stainless steel grade, also often referred to as 17-4 ； 17%Cr, 4%Ni