The advantages and disadvantages of the solid solution […]
The advantages and disadvantages of the solid solution process of stainless steel pipe fittings have a great influence on the corrosion resistance and appearance brightness of stainless steel, and play a decisive role in the processing performance of stainless steel. Therefore, the heat treatment process of stainless steel plays a very important role in the production of stainless steel pipe fittings.
1. Solution temperature. According to the characteristics of the chemical composition of stainless steel, the solid solution temperature of stainless steel needs to be 950-1150 degrees Celsius to achieve the softening effect, so that the hardness of stainless steel can be reduced to less than 220HV, and the quality requirements of pipeline installation and compression are met. If the temperature control is unreasonable, various quality defects are prone to occur.
2. Solution time. During the heating process of austenitic stainless steel, the residual ferrite content in the steel decreases with the prolongation of heating time. Therefore, the solution treatment of stainless steel pipe fittings should be controlled at about 1050 ℃, so that the carbon can reach a saturated state and improve the corrosion resistance. Then it is rapidly cooled in air to achieve a solid solution effect.
3. Solution speed and heat preservation. The thermal conductivity of stainless steel is low, and the thermal conductivity at room temperature is only 27% of that of carbon steel. Therefore, the heating process of stainless steel should be carried out slowly when heated at low temperature. If the heating speed is too fast, it is easy to produce deformation, the heating speed of stainless steel should be controlled during the solid solution, and attention should be paid to the holding time. Such as 316L steel at about 1100 ℃, the holding time is long, and the content of residual ferrite will continue to decrease.
In our solid solution production, the solid solution of stainless steel pipe fittings has to go through the process of heating - heat preservation - time cooling, and the whole process takes about 40 minutes.