Cryogenic treatment equipment processing technology

2020-04-23 08:37:00

 For cryogenic treatment (cryogenic treatment equipment) technology, the treatment process is the key to determine the treatment effect. The key influencing factors in the cryogenic treatment process include: cryogenic treatment method, temperature rising and falling speed, pre-tempering or post-tempering treatment, holding time, cryogenic times, etc.

      1. (Cryogenic treatment equipment) Cryogenic treatment method

      Can be divided into liquid method and gas method. The liquid method is to put the workpiece directly into liquid nitrogen, and the processing temperature is -150 ℃. The shortcoming of this method is that the thermal shock is large, sometimes even causing the workpiece to crack. The gas method uses the latent heat of vaporization of liquid nitrogen and low-temperature nitrogen to absorb heat for refrigeration. The processing temperature reaches -196 ℃, and the processing effect is better.

      2 Speed ​​of temperature rise and fall

      At present, there are two main views on the rate of rise and fall in cold temperatures. One view is that cryogenic temperature rise and fall should not be too fast, that is, it is not recommended to immerse the workpiece directly in liquid nitrogen, because quenching will cause increased stress inside the workpiece, which is likely to cause deformation or cracking of the workpiece. For example, in Japan's "Cryogenic Rapid Heating Method", the workpiece is not cold-treated immediately after quenching, but is first placed in a water bath, and then placed in the treatment tank for cold treatment at -80 ℃ or -180 ℃. In a 60C hot water bath, the sample is quickly returned to temperature to reduce internal stress, and then tempered at different temperatures for 1 hour.

      Another view is that it should be cooled or heated quickly, so that austenite can be more easily transformed into martensite, and the direct immersion cooling rate is slower than oil quenching, which is not easy to cause deformation or cracking of the material. Like the “impact method” of the former Soviet Union, the processed workpieces were quickly put into liquid nitrogen, cryogenically cooled to the required temperature, and then kept warm for 5-30 minutes, then taken out and placed at room temperature, after it returned to room temperature, Then temper in oil at 200 ~ 500 ℃ for 1h. This method significantly increases the service life of high-speed steel tools.

Nuoruida (Tianjin) science and Technology Co., Ltd. is committed to research, development, and sales of liquid nitrogen cryogenic equipment which is establish in 2002. 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.