Tempering of martensite stainless steel

There are a lot of seamless material, which is one of martensitic stainless steel, stainless steel seamless pipe market is a major production materials martensitic stainless steel, but the production of seamless steel pipe requires a series of processing, technology high complexity, tempered martensitic stainless steel is more important production processes. Tempering often use 200 ~ 300%: tempering to eliminate internal stress generated during quenching without causing significant changes within the steel structure for the purpose, and maintain high hardness stainless steel parts. Require high wear resistance, good flexibility and corrosion resistance of the mold, measuring tools, cutting tools and stainless steel springs and other components is commonly used after quenching and tempering. Tempering time is 2 ~ 4h, gets tempered martensite. Martensitic stainless steel after tempering is often used to quench tempering 600 to 750 percent, while tempering asked for 1 ~ 4h, get tempered sorbite to improve and enhance the strength and toughness martensitic stainless steel, etc. Mechanical properties for the purpose. The preliminary heat treatment can be done in order to prepare for the future organization of surface hardening, nitriding, etc., and to improve the workability of the steel. After tempering cooling faster, on the one hand to avoid temper brittleness, on the other hand tempering slow cooling will produce prop's body, so that the corrosion resistance is lowered. Martensitic stainless steel after quenching and tempering should be avoided in the range of 400 to 600 degrees. In order to avoid reduction of impact toughness (temper brittleness), and the corrosion caused by the precipitation of chromium carbides decreased. From the viewpoint of corrosion resistance, the use of low-carbon martensitic stainless steel and tempering more favorable. Martensitic stainless steel with high carbon content than martensitic stainless steel with low carbon content temper brittleness is more susceptible to cold formability, weldability worse. In general, high carbon martensitic stainless steel welding required before preheating, post weld heat treatment should preferably not be welded. Crl3 type martensitic stainless phase transition temperature of about 800%, the heating temperature exceeds 800% air-cooling can be achieved martensite. With the increase of quenching temperature, chromium carbide (Cr23c6) continuous dissolution, hardness and corrosion resistance is likewise rising. But when the heating temperature is more than 1050% after the strong carbide precipitation during tempering process, so reducing the corrosion resistance of the steel, and therefore crl3 type martensitic stainless steel quenching temperature should be selected. Crl3 type martensitic stainless steel tempering temperature selection should be based on conditions of use, the requirements of high hardness, high wear resistance of parts usually tempered at 200 to 250 degrees; if requiring high strength and good toughness, generally 600 to 750 degree of tempering. After tempering to be a faster cooling rate, generally using oil cooling temperatures. Tempering is taking air cooling.