MPI Metallurgical Processing
Providing metal treating & surface solutions
for precision parts & tooling since 1957!

Press & Plug Quenching

pressQsideWhen thin and flat components are to be hardened 'Press Quenching' is employed to maintain the flatness while hardening. During quenching it is held under a controlled force. Gears, liners bearing races are prone to dimensional changes during hardening and quenching, which can cause a number of problems during manufacturing operations. The objective of press quenching is to hold parts round and flat while they are being cooled, thereby reducing, though not eliminating, distortion.

Plug Quenching

Plug Quenching is designed for limiting the distortion of thin­walled components while hardening. During quenching, it is held on a plug of appropriate dimensions that is inserted into the component. Typical components rings, liners and spline gears.

Press Quench

The component part is removed from the furnace and placed onto the lower die in the out position. Initiation of the automatic cycle moves the lower die into the center section of the machine. When this is fully advanced, the upper ram assembly and dies descend, with an expander centering the part just prior to the inner and outer dies locating on their pressure points. When the expander and dies are properly located, the ram holding them is latched in the down position and pressure is applied to all three. The inner die, outer die and expander have completely independent pressure controls, regulated by hydraulic valve and monitoring with pressure gauges. The expander cone pushes out against the segmental lower die to hold the part round and to size. The inner and outer dies keep the part flat.

A guard completely encloses the upper dies and forms a quenching chamber. A circulation path within the press is created as the quench oil is pumped into the quench chamber through apertures around the outside diameter or through holes in the lower die. The Quench oil chamber fills the chamber around the component and flows out at the top.

Quality Assurance Considerations

Component design and manufacturing methods are the most critical in minimizing distortion. In engineering, the design should consider distor­tion from the initial concept through all phases of production.

Part Design

Quench press tooling designed specifically for the needs of the part can satisfactorily reduce distortion problems. Some of the major gains in quench pressing have come from appropriately addressing the manufacturing processes.