How are stainless steels classified?

In recent years due to the widespread use of stainless steel columns, stainless steel has also entered the public eye. Generally, the classification of stainless steel is divided into martensite type, ferrite type, austenite type, austenite ferrite type and precipitation hardening type according to the different microstructure inside the material

(a) the internal microstructure of martensite stainless steel in this kind of steel is martensite. The martensitic stainless steel, the network content is 12-17%, and 0.1-0.5% carbon (sometimes up to 1%). This type of steel can accept quenching, quenching hardness decreased, but the toughness increased, and the corrosion resistance is the best. 2 CR 13 martensitic stainless steel as an example, after quenching, tempering (1000-1050 'C) (660-770nC) after use, if after 800-900X: cold annealing, can improve the processing performance of it.

Martensitic stainless steel with high corrosion resistance, thermal stability and heat resistance, can make the temperature lower than 70 (below TC long-term work machine. Especially it is widely used in manufacturing the toughness and impact load requirements of the higher parts, such as turbine blades and medical equipment parts. Common brands are 2 CR 13 (2013).

(two) the internal microstructure of ferrite stainless steel is ferrite, the chromium content of less 16-30%. content when chromium, carbon contents are low, and when the chromium content in 30% when the carbon content should be increased to 0.35%. it does not rely on the quenching hardening.

This kind of steel has a unique phenomenon, that is, at 475 degrees C heating will cause this kind of steel embrittlement, but after more than 600 degrees C, the temperature is short time heating and air-cooled, will be able to restore to the original performance

This kind of steel has high corrosion resistance and oxidation resistance to corrosion than the martensitic stainless steel, especially in nitric acid and high chemical stability. Widely used in the manufacture of nitric acid plant of chemical equipment, such as absorption tower, heat exchanger, storage tank, transport for nitrate tank, pipeline and other manufacturing impact load bearing parts and equipment used. Grade 17, 17 chromium chromium titanium (Cr17/Crl7Ti).

(three) austenitic stainless steel, austenitic stainless steel, its microstructure is austenite, is suitable to add $nickel in high chromium stainless steel (8-25%) and the formation of this type of austenitic stainless steel. Austenitic stainless steel after heat treatment, the organization will not change, nor the grain become thinner. As with ferritic stainless steel no, the quenching to improve its hardness. This kind of steel is not magnetic, but after cold working hardening phenomenon occur easily.

Now the stainless steel column on the building material market is made of austenitic stainless steel, which is a widely accepted stainless steel column material in the industry.