Metal extrusion quenching method and system with variable length entry zone

Abstract

The specification discloses a metal extrusion quenching method and system in which multiple quenching steps are accomplished in multiple quenching zones. In a first zone, the extrusion is cooled relatively gently while the extrusion is in the pre-critical temperature range of the alloy of which the metal extrusion is fabricated. In a second zone, the extrusion is cooled relatively aggressively while the extrusion is in the critical temperature range. The first quenching zone includes a plurality of subzones each of which can be controlled independently. Consequently, the effective length of the first zone may be controlled by controlling the quenching provided in each subzone.

1 . A method of quenching a metal extrusion comprising:
 first quenching the metal extrusion in a first zone relatively gently when the temperature of the metal extrusion is approximately within the pre-critical temperature range of the alloy of which the metal extrusion is fabricated; and   second and subsequently quenching the metal extrusion in a second zone relatively aggressively and relatively quickly while the temperature of the metal extrusion is approximately within the critical temperature range of the alloy of which the metal extrusion is fabricated.   
     
     
         2 . A method as defined in  claim 1  wherein:
 the first zone comprises a plurality of subzones; and 
 the first quenching step includes selectively applying quenching in the subzones. 
 
     
     
         3 . A method as defined in  claim 2  wherein the selectively applying quenching step within each subzone includes turning quenching on or off. 
     
     
         4 . A method as defined in  claim 3  wherein the selectively applying quenching step within each subzone includes quenching with mist. 
     
     
         5 . A method as defined in  claim 1  wherein the first quenching step comprises quenching with mist. 
     
     
         6 . A quenching system for a metal extrusion comprising:
 a first quenching zone in which the metal extrusion is quenched relatively gently while the temperature of the metal extrusion is approximately within the pre-critical temperature range of the alloy of which the metal extrusion is fabricated; and   a second quenching zone in which the metal extrusion is quenched relatively quickly while the temperature of the metal extrusion passes is approximately within the critical temperature range of the alloy of which the metal extrusion is fabricated.   
     
     
         7 . A system as defined in  claim 6  wherein the first quenching zone comprises a plurality of subzones in which the metal extrusion is selectively quenched or not quenched in each of the subzones. 
     
     
         8 . A system as defined in  claim 7  wherein quenching can be turned on or off within each subzone. 
     
     
         9 . A system as defined in  claim 8  wherein any quenching within each subzone includes quenching with mist. 
     
     
         10 . A system as defined in  claim 6  wherein the metal extrusion within the first quenching zone is quenched with mist.