Development of the controlled atmosphere sealed hardening furnace abroad

The features of the construction of the modern controlled atmosphere hardening furnace are as follows :1) most furnaces are of through type, 2) radiant tubes are used for heating in common, 3) insulated with fireproof fiber. The controlled atmosphere systems are various. Thermocouple is still used for measuring the furnace temperature, but more than one thermocouple are used to measure temperature at different site in one furnace. Oxygen probe is frequently used. Since 70's, microprocessors are used to control more than one furnace in the production line .