Introduction of liquid nitrogen cryogenic processing process

2012-03-15 15:33:00

Liquid nitrogen cryogenic refrigerator products are widely used in mechanical engineering, metal materials, heat treatment engineering, environmental testing, rubber, medicine, food processing, medical research, plant preservation, aerospace, military, quality inspection and scientific research, colleges and universities and other fields .

Liquid nitrogen cryogenic tank processing process operation flow

   First, the furnace temperature

    1. Cryogenic treatment should be carried out immediately after the workpiece is quenched and cooled to room temperature, so as to avoid excessive heat retention at room temperature and austenite thermal stabilization.

    2. The cold treatment temperature is generally -60 ~ -80 degrees Celsius. The higher the steel carbon and alloy element content (mass fraction), the lower the Mf and the lower the cryogenic treatment temperature.

   Second, the cooling method

    1. The workpiece should not be directly placed in a thermal insulation cooling liquid (such as a mixture of alcohol and dry ice), but should be cooled in a low-temperature box filled with air.

    2. For workpieces with complex shapes and large sizes, they should be reduced from room temperature to processing temperature with the equipment to prevent the workpiece from cracking.

   Third, holding time

    1. The martensite transformation is mainly in the continuous cooling process. After the single-piece cold treatment reaches the temperature, the transformation can be completed after the transformation.

    2. When the amount of furnace is large, in order to ensure that the core of the workpiece reaches the cold processing temperature, it should be kept at the cold processing temperature for 1 ~ 3h.

   Fourth, the temperature rises

    1. After the cold treatment is completed, the workpiece is taken out of the cold processing equipment, returned to room temperature in the air, and the surface of the workpiece is wiped with frost in time and coated with anti-rust oil.

    2. Tempering can not be performed before reaching room temperature, and it should be tempered in time after reaching room temperature to prevent cracking.

   Five, low temperature tempering

    After cold treatment, the workpiece should be tempered at 160 ~ 180oC for 2h.

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The company also has cryogenic equipment, low temperature assembly boxes, and cryogenic processing equipment products.