Subzero treatment equipment for workpieces after heat treatment

The utility model provides subzero treatment equipment after heat treatment of workpieces, which comprises a refrigerating box, a liquid nitrogen tank and a closed box door, the liquid nitrogen tank is arranged on the right side of the refrigerating box, the closed box door is arranged in the middle of the front side of the refrigerating box, and a control panel is arranged on the left side of the front side of the closed box door. Compared with the prior art, the device has the advantages that the two temperature sensors are arranged, the two temperature sensors can detect the temperature value in the cryogenic cavity and transmit the temperature value to the single chip microcomputer, the single chip microcomputer compares the temperature value in the cryogenic cavity with the temperature value in the storage, when the temperature is too low, the single chip microcomputer can control the relay to be started, and therefore the cryogenic cavity is protected. The relay cuts off the current flowing through the