Austenitic stainless steel refers to stainless steel having an austenite structure at normal temperature. When the steel contains about 18% Cr, 8%-10% Ni, and about 0.1% C, it has a stable austenite structure. Austenitic chromium-nickel stainless steel includes the famous 18Cr-8Ni steel and high Cr-Ni series steel which is added with elements of Cr and Ni and added with elements such as Mo, Cu, Si, Nb and Ti. Austenitic stainless steel is non-magnetic and has high toughness and plasticity, but its strength is low. It is impossible to strengthen it by phase transformation. It can only be strengthened by cold working. If it is added with elements such as S, Ca, Se, Te, it has good Easy machinability.

In addition to corrosion resistance to oxidizing acid medium, such steels are resistant to corrosion by sulfuric acid, phosphoric acid, formic acid, acetic acid, urea, etc., if they contain elements such as Mo and Cu. If the carbon content of such steel is less than 0.03% or contains Ti or Ni, the intergranular corrosion resistance can be remarkably improved. High-silicon austenitic stainless steel has good corrosion resistance to concentrated nitric acid. Due to the comprehensive and good comprehensive properties of austenitic stainless steel, it has been widely used in various industries.

Austenitic stainless steel was introduced in Germany in 1913 and has always played the most important role in stainless steel. Its production and usage account for about 70% of total stainless steel production and consumption. The steel number is also the most. There are more than 40 grades of austenitic stainless steel commonly used in China. The most common one is the 18-8 type.

Austenitic stainless steel has good production performance, especially chrome-nickel austenitic stainless steel. It can smoothly produce plates, tubes, strips, wires, forgings and castings of various common specifications by conventional means of producing special steel. Due to the high content of alloying elements (especially chromium) and low carbon content, most of these stainless steel materials are produced by arc furnace plus argon oxygen decarburization (AOD) or vacuum deoxygenation decarburization (VOD). Batch products can be smelted in a vacuum or non-vacuum non-induction furnace, and if necessary, electroslag remelting.

The excellent thermoplasticity of chrome-nickel austenitic stainless steel makes it easy to apply hot working such as forging, rolling, hot perforation and extrusion. The heating temperature of steel ingot is 1150~1260 centigrade, the deformation temperature range is generally 900~1150centigrade, containing copper, Nitrogen and steel grades stabilized with titanium and niobium are biased towards low temperatures, while high chromium and molybdenum grades are biased by high temperatures. Due to poor thermal conductivity, the holding time should be longer. After hot processing, the workpiece can be air-cooled. The chromium-manganese austenitic stainless steel has strong sensitivity to hot cracking, and the steel ingot should be smallly deformed and multi-passed when the billet is opened, and the forging should be cold. Cold working processes such as cold rolling, cold drawing, and spinning can be performed, as well as forming operations such as punching, bending, crimping, and folding. The work hardening tendency of chrome-nickel austenitic stainless steel is weaker than that of chrome-manganese steel. The cold deformation after one annealing can reach 70%~90%, but the chromium-manganese austenitic stainless steel has strong deformation resistance and strong work hardening tendency, and should increase the intermediate softening. The number of annealings. Generally, the intermediate softening annealing treatment is water-cooling at 1050~1100 centigrade.

Austenitic stainless steel can also produce castings. In order to improve the fluidity of molten steel and improve the casting performance, the composition of the cast steel alloy should be adjusted: increase the silicon content, relax the range of chromium and nickel content, and increase the upper limit of the impurity element sulfur content.

Austenitic stainless steel should be solution treated before use to maximize the solid solution of various precipitates such as carbides in the steel into the austenite matrix, and also to homogenize the structure and eliminate stress, thus ensuring excellent Corrosion resistance and mechanical properties. The correct solution treatment system is water-cooled after heating at 1050~1150 centigrade (thin pieces can also be air-cooled). The solution treatment temperature depends on the degree of alloying of the steel: no molybdenum or low molybdenum steel should be lower (��1100 centigrade), and higher alloying grades such as 00Cr20Ni18Mo-6CuN, 00Cr25Ni22Mo2N should be higher (1080~1150) centigrade).

Advanced technologies are widely used in production. For example, the refining rate outside the furnace is over 95%, and the continuous casting ratio is over 80%. High-speed rolling mills and precision and fast forging machines are widely promoted. In particular, electronic computer control is realized during smelting and processing to ensure reliable and stable product quality and performance.