The purpose of heat treatment of stainless steel tube is mainly to change the metal matrix in steel pipe, improve the hardness of stainless steel tube. But can not fundamentally change the shape of steel pipe organization, and thus can not be more effective to improve the strength and toughness of stainless steel tube. Stainless steel tube quenching temperature should be selected in the actual critical temperature above 30-70 ℃, due to poor thermal conductivity of steel, holding time is generally about double the increase in steel. At the same time, in order to reduce the quenching stress, quenching should be pre-cooling in the air, quenching medium generally use oil, force to avoid quenching, you can also take early oil (cold to 200-300 ℃) air-cooled approach.Stainless steel plate prices

After quenching the stainless steel tube, the matrix structure can be martensite or talc, high temperature tempering into tempering sorbite, which is quenched and tempered, stainless steel tube tempering process and other steel pipe tempering is no essential difference , Stainless steel quenching should be timely tempering. Stainless steel pipe can also beothermal quenching. The isothermal quenching and cooling medium may be hot oil or nitrate, for example, at 830-870 ° C, heated and then quenched into 280-350 ° C nitrite. Alloy steel tube quenched and tempered or isothermal quenching, the mechanical properties of ordinary gray cast iron significantly improved.Stainless Steel Sheet Price In China

In order to improve the surface hardness and wear resistance of stainless steel tube, can be flame surface hardening, high frequency surface hardening and chemical heat treatment, including high frequency or intermediate frequency surface quenching applications up. High and medium frequency surface quenching with a short heating time, less oxidative decarburization, deformation is small, simple operation, etc., usually using the heating temperature of 850-950 ℃, because the stainless steel tube thermal conductivity is poor, the melting point is low, the heating rate should not be too fast, otherwise Prone to melting or cracking. High and medium frequency stainless steel pipe can not only improve the surface hardness and wear resistance, but also significantly improve the fatigue strength, increase the service life, in addition, machine tool rail contact surface heating is also a typical example of stainless steel surface hardening. In order to get a good matrix structure, to ensure that the mechanical properties of stainless steel tube and surface hardening can get a higher hardness, the surface heat treatment is best before the first normalizing or quenching and tempering treatment.stainless steel sheet and coil supplier

Stainless steel tube chemical heat treatment is the most nitriding, gas nitriding is in the 500-580 ℃ ammonia, nitriding time of about 50-90 hours, the general nitriding layer depth of 0.1-0.4 mm. Gas nitriding is best used with chromium, aluminum and molybdenum alloy steel pipe. Because chromium and aluminum can combine with nitrogen to form a stable hardness of the nitride, such as AIN, CrN, Cr2N, molybdenum can eliminate temper brittleness. Some stainless steel tube plant using salt bath active nitriding, the salt bath formula for the urea, sodium carbonate, potassium carbonate to 6: 3: 1 mixed melting, nitriding 60-180 minutes, that can get a certain thickness of the diffusion layer, Wear resistance and fatigue strength has improved significantly.2b surface 304 stainless steel plate supplier