WORKPIECES THERMAL TREATMENT LINE Russian patent published in 1995 - IPC

FIELD: workpieces thermal treatment lines. SUBSTANCE: continuous-action line 20, uses at least two successively connected rotary-hearth furnaces. Rotary-hearth case hardening furnace 30, rotary-hearth balancing furnace 34 and rotary-heart diffusion furnace 32, installed between the case hardening and balancing furnaces, provide for the discharge of trays 46, 47 from any point at any time by way of suitable turning of furnace hearth and simultaneous treatment in each rotary-hearth furnace with different time of treatment cycle. Each toroid-shaped rotary-hearth furnace has one or several pushers 56 with a closed (enclosed in a holder) chain, installed in a vertical position in the central space (hole); the case hardening furnace is separated into several zones and has wall-mounted fans 44 for a uniform circular control of gaseous atmosphere in the furnace annular chamber. Two different hardening devices 200 and 214 in device 202 are used for slow cooling near several outlets 186, 187, 188. The balancing furnace provides for using of different cooling and hardening processes for the selected workpieces; it is possible only to return the workpieces from the device for slow cooling in the balancing furnace for repeated heating. EFFECT: enhanced efficiency. 16 cl, 9 dwg