Improvement, isothermal, normalization, tension correction and alike heat treatments of forge parts formed from carbon steels, improvement steels, cementation steels, micro composition steels and speacial quality steel provided according to customer demands are performed in automatic driven continous type and deep well type furnaces. Also, controlled cooling operations of forge parts produced from various micro composition material from forging temperature are performed by modern controlled cooling conveyors. Necessary completing processes after heat treatment and forging in completing lines are applied.