Stainless steel tubes can be divided into Cr series (400 series), Cr-Ni series (300 series), Cr-Mn-Ni (200 series) and precipitation hardening system (600 series) according to their composition. 200 series¡ªchrome-nickel-manganese austenitic stainless steel 300 series¡ªchrome-nickel austenitic stainless steel.
301 —– Good ductility, used for molded products. It can also be hardened by mechanical processing. Good weldability. Abrasion resistance and fatigue strength are better than 304 stainless steel.
302 —– Corrosion resistance is the same as 304, because the carbon content is relatively high and 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 grade is 0Cr18Ni9. 309¡ªhas better temperature resistance than 304.
316 —– After 304, the second most widely used steel type is mainly used in the food industry, pharmaceutical industry and surgical equipment. The addition of molybdenum element to make it have a special structure resistant to corrosion. Because it has better resistance to chloride corrosion than 304 stainless steel pipe, it is also used as "marine steel". SS316 is usually used in nuclear fuel recovery equipment. 18/10 grade stainless steel tubing also generally meets this application level.
Model 321-Similar to 304 except that the addition of titanium reduces the risk of corrosion of the material's weld seam.
400 Series-Ferritic and Martensitic Stainless Steel.
408¡ªGood heat resistance, weak corrosion resistance, 11% Cr, 8% Ni.
409¡ªThe cheapest model (British and American), usually used as car exhaust pipe, is a ferritic stainless steel (chrome steel).
410¡ªMartensite (high-strength chromium steel), has good abrasion resistance and poor corrosion resistance.
416¡ªThe addition of sulfur improves the processability of the material.
420¡ª "Blade grade" martensitic steel, similar to the earliest stainless steel of Brinell high chromium steel. Also used in surgical knives, it can be made very bright.
430¡ªFerritic stainless steel, for decoration, such as for car accessories. Good moldability, but poor temperature resistance and corrosion resistance.
440¡ªHigh-strength cutting tool steel with slightly higher carbon content. After proper heat treatment, it can obtain higher yield strength and hardness can reach 58HRC. It belongs to the hardest stainless steel. The most common application example is the "razor blade". There are three commonly used models: 440A, 440B, 440C, and 440F (easy to process).
500 Series¡ªHeat-resistant chrome alloy steel.
600 Series¡ªMartensitic precipitation hardened stainless steel tube.