Fluidised bed for heat-treating small objects - esp the isothermal quenching of iron shot

摘要

In a process for the heat treatment of small objects, esp. metal shot, fed into a fluidised bed of refractory particles heated to the treatment temp., the geometric configuration of the bed and the size of the particles are selected to produce a mixt. of particles and shot held at a constant treatment temp. for a specific time for all the shot and, finally the treated shot is separated from the refractory particles. The process is pref. applied in the isothermal quenching of the metal shot by injecting water into the fluidised bed, the water evaporating and thereby cooling the shot; the shot is pref. sepd. magnetically and the refractory particles recycled. Provides effective isothermal quenching of the shot without causing cooling cracks, and the shot does not require subsequent pickling.