The Flooring Expert

Stainless steel pipes can be divided into Cr series (400 series), Cr-Ni series (300 series), Cr-Mn-Ni (200 series) and precipitation hardening series (600 series) according to their composition.

200 series-chromium-nickel-manganese austenitic stainless steel 300 series-chromium-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—–The corrosion resistance is the same as that of 304, because the carbon content is relatively high, the strength is better.

303—–It is easier to cut than 304 by adding a small amount of sulfur and phosphorus.

304—–namely 18/8 stainless steel. The GB grade is 0Cr18Ni9.　309—Compared with 304, it has better temperature resistance.

316—–After 304, the second most widely used steel grade is mainly used in the food industry, pharmaceutical industry and surgical equipment. The addition of molybdenum makes it a special corrosion-resistant structure. Compared with 304 stainless steel pipe, it has better resistance to chloride corrosion, so it is also used as “marine steel”. SS316 is usually used in nuclear fuel recovery devices. 18/10 grade stainless steel pipe usually also meets this application level.

Model 321—Except for the addition of titanium to reduce the risk of corrosion of the material welds, other properties are similar to 304.

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 a car exhaust pipe, is a ferritic stainless steel (chrome steel).

410—Martensite (high-strength chromium steel), good wear resistance, poor corrosion resistance.

416—Sulfur is added to improve the processing performance 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 knives, which can be very bright.

430—Ferritic stainless steel, for decoration, such as car accessories. Good formability, but poor temperature resistance and corrosion resistance.

440—High-strength cutting tool steel with slightly higher carbon content. After proper heat treatment, higher yield strength can be obtained. The hardness can reach 58HRC, which is among the hardest stainless steels. The most common application example is the “razor blade”. There are three commonly used models: 440A, 440B, 440C, and 440F (easy processing type).

500 series—heat-resistant chromium alloy steel.

600 series—Martensitic precipitation hardening stainless steel pipes.