How Many Grades Of Stainless Steel Are There? Various Grades Of Performance Characteristics And Application Introduction

There are many types of stainless steel, stainless steel classification according to the composition can be divided into:

2XX series - chromium - nickel - manganese series austenitic stainless steel;

3XX series - chromium - nickel series austenitic stainless steel;

4XX series - high chromium series ferritic and martensitic steels;

5XX Series - Low Chromium Series Heat Resistant Steels Martensitic Steels;

Series 6XX - Precipitation hardening steels;

The most commonly used series here are 2XX/3XX/4XX, specifically each large series is divided into many fine grades, such as 201,202,304,316,416 and so on.

Each series of commonly used grades of stainless steel characteristics and applications:

200 series stainless steel belongs to low nickel and high manganese stainless steel, nickel content of 4%~6%, manganese content of 8% or so, is a nickel-saving stainless steel. Due to the resistance to intergranular corrosion and pitting corrosion resistance is significantly lower than the 300 series stainless steel, 200 series stainless steel's biggest advantage is that it is relatively inexpensive compared to the 300 series stainless steel. Under the premise of weak corrosion, 202 stainless steel can almost completely replace the 304 stainless steel, in addition to 200 series stainless steel with austenitic steel non-magnetic properties, the appearance is similar to 304, the market is often substandard, pretending to be "304" sales phenomenon;

202 stainless steel: under the premise of weak corrosion, 202 stainless steel can almost completely replace 304 stainless steel, widely used in building decoration, municipal engineering, highway guardrail, hotel facilities, shopping malls, glass handrails, public facilities and other places;

301 stainless steel: good ductility, used for molding products, but also through work hardening, good weldability, wear resistance and fatigue strength is better than 304 stainless steel;

302 stainless steel: corrosion resistance with 304, corresponding to the domestic grade 1Cr18Ni9, due to the relatively high carbon content and therefore better strength, commonly used in construction of decorative parts;

303 stainless steel: is a free cutting stainless steel containing sulfur and selenium, used for the main requirements of easy cutting and high surface finish occasions, most suitable for automatic lathes, bolts and nuts;

304 stainless steel: is the most common type of stainless steel material, density of 7.93 g/cm3, the industry is also called 18/8 stainless steel, high temperature resistance of 800 degrees, with good processing performance, high toughness, widely used in industrial and furniture decoration industry and food medical industry;

309 stainless steel: compared to 304 has better temperature resistance, steel production is more 309S stainless steel, corrosion resistance, high temperature performance is better; can withstand high temperatures of 980 ° C, mainly used in the boiler, chemical industry, 309 and 309S compared to the sulfur S content.

316 stainless steel: after 304, the second most widely used steel, due to the addition of Mo elements, so that its corrosion resistance, and high-temperature strength has been greatly improved, high temperature resistance can reach 1200-1300 degrees, can be used in harsh conditions; corrosion resistance: corrosion resistance is better than 304 stainless steel, in the production process of pulp and paper has good corrosion resistance. And 316 stainless steel is also resistant to marine and aggressive industrial atmospheres.316 stainless steel national standard grade (06Cr17Ni12Mo2) has good oxidation resistance. In the range of 427°C-857°C (800°F-1575°F), it is best not to use 316 stainless steel continuously, but when 316 stainless steel is used continuously outside this temperature range, the stainless steel has good heat resistance;

316L stainless steel: better resistance to carbide precipitation than 316 stainless steel, available in the above temperature range. The biggest difference in the use of 316L ultra-low carbon, so when welding, 316L carbon is not easy to precipitate and chromium combined into chromium carbide, which can reduce the corrosion phenomenon of the welded part;

321 stainless steel: in addition to the addition of titanium elements to reduce the risk of material weld corrosion other properties similar to 304;

408 stainless steel: good heat resistance, weak corrosion resistance, 11% Cr, 8% Ni;

409 stainless steel: the cheapest type (British and American), usually used as automobile exhaust pipes, is a ferritic stainless steel (chromium steel);

410 stainless steel: martensitic (high-strength chromium steel), good wear resistance, poor corrosion resistance;

416 stainless steel: added sulfur to improve the machinability of the material, easy cutting martensitic stainless steel, can be strengthened by heat treatment, 416 strength and cutting processability than 304 and 316 good, small coefficient of friction, stainless steel with low carbon content, good corrosion resistance, but corrosion resistance is not as good as 304 and 316;

420 stainless steel: "cutting edge level" martensitic steel, with a certain degree of wear resistance and corrosion resistance, hardness and other characteristics, similar to the earliest stainless steel Brinell high-chromium steel. Also used for surgical knives, can be made very bright. 420 stainless steel is suitable for all kinds of precision machinery, bearings, electrical, equipment, instruments, meters, transportation tools, household appliances. Mostly used in the manufacture of parts resistant to corrosion by atmosphere, water vapor, water and oxidizing acids;

430 stainless steel: ferritic stainless steel, is a general-purpose steel with good corrosion resistance, better thermal conductivity than austenitic, coefficient of thermal expansion is smaller than austenitic, heat fatigue, add stabilizing element titanium, weld parts with good mechanical properties. 430 stainless steel is used for automotive accessories, architectural decorative, fuel burner parts, household appliances, home appliance parts;

430F stainless steel: in 430 steel plus easy cutting performance of steel, mainly used in automatic lathes, bolts and nuts, etc.;

440 stainless steel: high-strength cutting edge steel, slightly higher carbon content, after appropriate heat treatment can obtain high yield strength, hardness can reach 58HRC, belong to the hardest stainless steel. The most common application example is "razor blade". There are three commonly used types: 440A, 440B, 440C, and 440F (easy to process);

Stainless steel 443: a ferritic stainless steel, now generally used to replace 304, rust resistance and processing performance is comparable to 304, is now in the field of electrical appliances, utensils, kitchen equipment, elevators, oven production and other areas of full promotion;

500 series: heat-resistant chromium alloy steel;

600 series: martensitic precipitation hardening stainless steel;

630: the most commonly used precipitation-hardening stainless steel type, often also called 17-4; 17% Cr, 4% Ni;