Stainless steel pipe is a kind of hollow long round steel, which is widely used in industrial transmission pipelines and mechanical structural components such as petroleum, chemical industry, medical treatment, food, light industry, machinery and instruments, etc. In addition, when the bending and torsional strength are the same, the weight is light, so it is also widely used in the manufacture of mechanical parts and engineering structures. It is also commonly used as furniture, kitchenware, etc.

Stainless steel pipes can be divided into CR series (400 Series), Cr Ni series (300 Series), Cr Mn Ni series (200 Series) and precipitation hardening series (600 Series).

200 series - chromium nickel manganese austenitic stainless steel 300 series - chromium nickel 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, so the strength is better.

303 ------ it is easier to cut than 304 by adding a small amount of sulfur and phosphorus.

304 - 18 / 8 stainless steel. The GB brand is 0Cr18Ni9. 309-304 has better temperature resistance than 304.

316 ------ the second most widely used steel after 304, which is mainly used in food industry, pharmaceutical industry and surgical equipment. Adding molybdenum makes it obtain a special corrosion-resistant structure. Compared with 304 stainless steel pipe, it has better chloride corrosion resistance, so it is also used as "marine steel". SS316 is usually used in nuclear fuel recovery units. Grade 18 / 10 stainless steel pipes generally also meet this application grade.

Model 321 - other properties are similar to 304 except that the risk of weld corrosion of the material is reduced due to the addition of titanium.

400 series - Ferritic and martensitic stainless steel.

408 - good heat resistance, weak corrosion resistance, 11% Cr, 8% Ni.

409 - the cheapest model (British and American), usually used as automobile exhaust pipe, is ferritic stainless steel (chromium steel).

410 - martensite (high strength chromium steel), with good wear resistance and poor corrosion resistance.

416 - adding sulfur improves the processability of the material.

420 - "cutting tool grade" martensitic steel, similar to the earliest stainless steel such as Brinell high chromium steel. It is also used for surgical tools, which can be made very bright.

430 - ferritic stainless steel for decoration, such as 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 appropriate heat treatment, and the hardness can reach 58hrc. It is one of 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 - Martensitic precipitation hardening stainless steel pipe.