Stainless steel classification

Stainless steel classification
Shijiazhuang Jingjin Mechanical Equipment Installation Co., Ltd. -- Zhou Yanhui 13833456715
1、 304: general model; 18/8 stainless steel. Products such as: corrosion resistant containers, tableware, furniture, railings, medical equipment. The standard composition is 18% chromium plus 8% nickel. It is a non-magnetic stainless steel whose metallographic structure cannot be changed by heat treatment. GB grade is 0Cr18Ni9.
2、 2B: Fog surface; After cold rolling, the surface is moderately bright after heat treatment, pickling and finish rolling. Because the surface is smooth, it is easy to regrind, making the surface more bright and widely used, such as tableware, building materials, etc. After surface treatment with improved mechanical properties, it can be used for almost all purposes.
Stainless steel can be divided into Cr series (400 series), Cr Ni series (300 series), Cr Mn Ni series (200 series), heat-resistant chromium alloy steel (500 series) and precipitation hardening series (600 series) according to composition.
200 series: Cr Mn Ni
201202, etc.: manganese is used instead of nickel, which has poor corrosion resistance and is widely used as a cheap substitute for 300 series in China
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 superior to 304 stainless steel.
302: The corrosion resistance is the same as 304, and the strength is better due to the relatively high carbon content.
303: It is easier to machine than 304 by adding a small amount of sulfur and phosphorus.
304: general model; 18/8 stainless steel. Products such as: corrosion resistant containers, tableware, furniture, railings, medical equipment. The standard composition is 18% chromium plus 8% nickel. It is a non-magnetic stainless steel whose metallographic structure cannot be changed by heat treatment. GB grade is 0Cr18Ni9.
304 L: It has the same characteristics as 304, but is low in carbon, so it is more corrosion resistant and easy to heat treat, but has poor mechanical property, and is suitable for welding and not easy to heat treat.
304 N: It is a nitrogen containing stainless steel with the same characteristics as 304. Nitrogen is added to improve the strength of the steel.
309: better temperature resistance than 304, up to 980 ℃.
309S: It has a lot of chromium and nickel, so it has good heat resistance and oxidation resistance. Products such as heat exchanger, boiler components and injection engine.
310: Excellent high-temperature oxidation resistance, with the maximum operating temperature of 1200 ℃.
316: After 304, the second most widely used steel is mainly used in food industry, clock and watch accessories, pharmaceutical industry and surgical equipment. Molybdenum is added to obtain a special corrosion resistant structure. As it has better chloride corrosion resistance than 304, it is also used as "marine steel". SS316 is usually used in nuclear fuel recovery devices. Grade 18/10 stainless steel generally conforms to this application grade.
316 L: Low carbon, so it is more corrosion resistant and easy to heat treat. Products such as chemical processing equipment, nuclear power generator and refrigerant storage tank.
321: Other properties are similar to 304 except that the addition of titanium reduces the risk of corrosion of material welds.
347: Stabilized element niobium is added, which is suitable for welding aviation appliance parts and chemical equipment.
400 series: ferritic and martensitic stainless steel, manganese free, can replace 304 stainless steel to some 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, is of ferritic stainless steel (chromium steel).
410: martensite (high-strength chromium steel), with good wear resistance and poor corrosion resistance.
416: The addition of sulfur improves the processability of the material.
420: "Tool grade" martensitic steel, similar to the earliest stainless steel such as Brinell high chromium steel. It is also used for surgical knife, which can be made very bright.
430: Ferritic stainless steel, used for decoration, such as automobile 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: martensitic precipitation hardening stainless steel.
Stainless steel surface finish grade
Original surface: No.1 hot rolled surface subject to heat treatment and pickling treatment. It is generally used for cold rolling materials, industrial tanks, chemical industrial devices, etc. The thickness is from 2.0mm to 8.0mm.
Blunt surface: NO.2D cold rolled, heat treated and pickled, with soft material and silver white luster on the surface, used for deep stamping, such as automobile components and water pipes.
Fog surface: the surface of NO.2B is moderately bright after cold rolling, heat treatment, pickling, and finish rolling. Because the surface is smooth, it is easy to regrind, making the surface more bright and widely used, such as tableware, building materials, etc. After surface treatment with improved mechanical properties, it can be used for almost all purposes.
Coarse sand No. 3 is the product grinded with 100-120 # abrasive tape. It has better glossiness and discontinuous coarse lines. It is used for building interior and exterior decoration materials, electrical products, kitchen equipment, etc.
Fine sand: No. 4 product is ground with 150-180 abrasive belt. It has better glossiness, discontinuous coarse lines, and the stripes are thinner than No. 3. It is used for bath, decoration materials inside and outside buildings, electrical products, kitchen equipment, food equipment, etc.
#320 Products ground with No. 320 abrasive tape. It has better glossiness, discontinuous coarse lines, and the stripes are thinner than NO. 4. It is used for bath, interior and exterior decoration materials, electrical products, kitchen equipment, food equipment, etc.
Hairline: HLNO.4 is the product with grinding pattern generated by continuous grinding of polishing abrasive belt with appropriate grain size (subdivided into 150-320). It is mainly used for building decoration, elevators, doors and panels of buildings.
Bright surface: BA is cold rolled, bright annealed and leveled. Excellent surface gloss and high reflectivity. A mirror like surface. Used for household appliances, mirrors, kitchen equipment, decorative materials, etc