Classification of stainless steel:
Precipitation hardening stainless steel
With good formability and good weldability, it can be used as ultra-high strength material in nuclear industry, aviation and aerospace industry.
It can be divided into CR system (400 Series), Cr Ni system (300 Series), Cr Mn Ni system (200 Series), heat resistant Cr alloy steel (500 Series) and precipitation hardening system (600 Series).
200 Series: Cr Mn Ni
201202 and so on: Manganese instead of nickel has poor corrosion resistance and is widely used as a cheap substitute for 300 Series in China
300 series: Cr Ni austenitic stainless steel
301: good ductility, used for molding products. It can also be hardened rapidly by machining. Good weldability. The wear resistance and fatigue strength are better than 304 stainless steel.
302: the corrosion resistance is the same as 304, because the carbon content is relatively high, the strength is better.
303: by adding a small amount of sulfur and phosphorus, it is easier to cut than 304.
304: general purpose model; i.e. 18 / 8 stainless steel. Products such as: corrosion resistant containers, tableware, furniture, railings, medical equipment. The standard composition is 18% chromium and 8% nickel. It is a non-magnetic stainless steel whose metallographic structure can not be changed by heat treatment. GB grade is 06cr19ni10.
304 L: the same characteristics as 304, but low carbon, so it is more corrosion-resistant, easy to heat treatment, but poor mechanical properties, suitable for welding and not easy to heat treatment products.
304 n: it is a kind of stainless steel containing nitrogen with the same characteristics as 304. The purpose of adding nitrogen is to improve the strength of the steel.
309: it has better temperature resistance than 304, and the temperature resistance is as high as 980 ℃.
309 s: with a large amount of chromium and nickel, it has good heat resistance and oxidation resistance, such as heat exchanger, boiler components and injection engine.
310: excellent high-temperature oxidation resistance, the maximum use temperature of 1200 ℃.
316: after 304, the second most widely used steel grade is mainly used in food industry, watch and clock accessories, pharmaceutical industry and surgical equipment. Adding molybdenum element makes it obtain a special anti-corrosion structure. Because of its better resistance to chloride corrosion than 304, it is also used as “marine steel”. SS316 is usually used in nuclear fuel recovery devices. Grade 18 / 10 stainless steel generally meets this application grade.
316L: low carbon, so it is more corrosion resistant and easy to heat treatment. Products such as chemical processing equipment, nuclear power generator, refrigerant storage.
321: other properties are similar to 304 except that the risk of weld corrosion is reduced due to the addition of titanium.
347: adding stabilizing element niobium, suitable for welding aviation appliance parts and chemical equipment.
400 series: Ferritic and martensitic stainless steel, manganese free, can replace 304 stainless steel to a certain extent
408: good heat resistance, weak corrosion resistance, 11% Cr, 8% Ni.
409: the cheapest model (British and American), usually used as automobile exhaust pipe, belongs to ferritic stainless steel (chromium steel).
410: martensite (high strength chromium steel), good wear resistance, poor corrosion resistance.
416: the addition of sulfur improves the processability of the material.
420: “cutting tool grade” martensitic steel, similar to Brinell high chromium steel, the earliest stainless steel. It’s also used for surgical knives. It’s very bright.
430: ferritic stainless steel, decorative, for example, automotive accessories. Good formability, but poor temperature resistance and corrosion resistance.
440: high strength cutting tool steel, with slightly higher carbon content, can obtain higher yield strength after proper heat treatment, and the hardness can reach 58hrc, which is among the hardest stainless steels. The most common application example is “razor blade”. There are three common models: 440A, 440b, 440C, and 440f (easy to process).
500 Series: heat resistant chromium alloy steel.
600 Series: Martensite Precipitation Hardening Stainless steel.
Stainless steel mesh
Stainless steel screen is also called stainless steel filter screen because it is mainly used for filtering products.
Material: SUS201, 202, 302, 304, 316, 304L, 316L, 321 stainless steel wire, etc.