The Significance of the Tool Cold Treatment Process

2020-04-20 07:59:00

 It is understood that the cold treatment process of the tool means that the termination point of martensite transformation will drop to a low temperature below 0 ° C. After quenching, the structure contains a large amount of residual austenite. After quenching, the workpiece is put in cold agent or refrigerator to continue cooling.

    The freezing temperature should be selected according to the chemical composition (Mf point) of the steel. For most steels, dry ice, alcohol mixture (-78 ℃) can meet the requirements. Ice cooling treatment should be carried out immediately after quenching, so as to avoid stabilization of residual austenite caused by long-term storage and affect the effect of cold treatment. To avoid cracks during cold treatment, some workpieces with complex shapes can be cold-treated after one tempering. For some workpieces that require higher dimensional stability, such as thread gauges, it is often necessary to cold treat twice. The cold treatment must be tempered or aged to eliminate the formed stress and stabilize the newly formed martensite structure.

    The workpiece does not need to be kept warm during the cold treatment, only when its core reaches the temperature of cold agent (generally 1 ~ 2h). After the ice-cooling treatment, the workpiece is taken out from the cold agent, and the temperature is slowly raised to room temperature in the air, and then tempered. The temperature of ice-cooling is mostly from -70 ℃ to -80 ℃. The temperature of ice-cooling is mainly based on the MS (martensite transformation start temperature) and Mf (end temperature of martensite transformation) of steel The technical requirements of the parts are relevant. Ms <T <Mf. It is not that the lower the temperature, the better, as long as it meets the technical requirements. Low carbon alloy carburized steel is mostly -70 ℃ ~ -80 ℃.

    The ice-cooling process has its own value. The machine processed by the ice-cooling process has other characteristics that cannot be compared with yours. For example, the air turbine refrigerator is manufactured according to the basic principle of compressed air expansion refrigeration. Its characteristics are remarkable. It has fast cooling speed and can quickly reach the process temperature. Second, the environment is free of pollution and the cooling medium is compressed air. Third, the operating temperature range is wide and frost-free. Fourth, the separation of the freezer and the low-temperature box is convenient for upgrading. * The main thing is that it is simple to operate and easy to maintain.

    The tool ice-cooling process is scientifically manufactured according to the chemical composition of the steel. These technologies are applied to tools, measuring tools, and precision instruments, which not only improve the use value of the product, but also greatly improve the work efficiency.

Nuoruida (Tianjin) science and Technology Co., Ltd. is committed to research, development, and sales of liquid nitrogen cryogenic equipment. Using European technology, we provide a variety of equipment. The main equipment is liquid nitrogen equipment, cryogenic furnace, cryogenic processing equipment, low temperature assembly equipment, cryogenic assembly equipment, and so on.