High-Pressure Quenching--A New Solution for Heat-Treating Problems.

High-pressure quench vacuum furnaces can be used for hardening, tempering, annealing, brazing and solution heat treating. VPT furnaces are available from Seco/Warwick, Meadville, Pennsylvania, in cooling pressures of 6 and 10 bar with enhancements available to cool above 10 bar. These furnaces also can be configured either in a vertical or horizontal position.

To minimize cycle time and improve quality, the company incorporates a unique gas nozzle/flap system into this furnace. Wide-band, lightweight curved graphite heating elements are positioned completely around the work in the furnaces' cylindrical chamber. This design allows convection heat transfer and provides ideal heat uniformity throughout the workload from ambient to 1400F (760C).

Convection heating's advantages include:

* reduction of cycle time up to 50%;

* improvement of temperature uniformity during heating;

* improvement of metallurgical results;

* reduction of part distortion;

* single cycle tempering and hardening;

* reduction of pre-heat stages;

* reduction of post-treatment grinding and machining.

For uniform cooling, graphite nozzles are arranged 360[degrees] around the workload in the side wall and on the door assembly. The nozzles, covered by flaps while heating, open during cooling to inject gas into the hot zone chamber. The cooling gas is injected at a high velocity to improve load penetration ensuring a uniform cooling process. Hot gas escapes through the chamber's gas outlet bung in the rear wall.

Optional isothermal quenching monitors surface and core part temperature and controls the rate of cooling to minimize part distortion.

The furnace systems are fully automated. A computer-based PLC/PC system controls, monitors and regulates all vital operation of the furnace. The optional Wonderware In Touch software provides an interface, enabling the operator to control the process by using graphical display screens of the furnace and its related components.