Heat Treatment System

Abstract

A nitrogen enriched layer is formed in a primary heat treatment, and requenching is conducted in a secondary heat treatment, while the heat treatment efficiency is improved across the entire system. In a primary heat treatment device 1 , a bearing component is heated in a heater 11 at a temperature exceeding the A1 transformation point, and is then cooled in a cooler 12 to a temperature less than the A1 transformation point, thus forming a nitrogen enriched layer at the surface of the component. The bearing component that has undergone primary heat treatment is then subjected to high frequency heating in a heater 21 of a secondary heat treatment device 2 , at a temperature exceeding the A1 transformation point, and is then cooled in a cooler 22 to a temperature less than the A1 transformation point. Following cooling by the cooler 22 , the component is tempered using high frequency heating.

1 . A heat treatment system comprising: a primary heat treatment device for heating a steel component at a temperature exceeding the A1 transformation point and then cooling the component to a temperature less than the A1 transformation point, thus forming a nitrogen enriched layer at the surface of the component; and a secondary heat treatment device for heating the steel component that has undergone primary heat treatment, at a temperature exceeding the A1 transformation point, and then cooling the component to a temperature less than the A1 transformation point, wherein the secondary heat treatment device includes an induction heater, and tempering is performed by induction heating following cooling within the secondary heat treatment device.  
   
   
       2 . A heat treatment system comprising: a primary treatment device for heating a steel component at a primary heating temperature exceeding the A1 transformation point and then cooling the component to a temperature less than the A transformation point, thus forming a nitrogen enriched layer at the surface layer of the component; and a secondary treatment device for heating the steel component that has undergone heat treatment by the primary treatment device, at a secondary heating temperature exceeding the A1 transformation point, and then cooling the component to a temperature less than the A1 transformation point.  
   
   
       3 . A heat treatment system as claimed in  claim 2 , wherein 
 the primary treatment device includes a heater for conducting gas carbonitriding.    
   
   
       4 . A heat treatment system as claimed in  claim 2 , wherein 
 die quenching is conducted within the secondary treatment device.    
   
   
       5 . A heat treatment system comprising: a primary heat treatment device for heating a steel component at a temperature exceeding the A1 transformation point and then cooling the component to a temperature less than the A1 transformation point, thus forming a nitrogen enriched layer at the surface of the component, and a secondary heat treatment device for heating the steel component that has undergone primary heat treatment, at a temperature exceeding the A1 transformation point, and then cooling the component to a temperature less than the A1 transformation point, wherein induction heating is conducted in the secondary heat treatment device, the temperature of the steel component undergoing induction heating is detected, and the induction heater is operated under feedback control based on the detected temperature value.  
   
   
       6 . A heat treatment system as claimed in  claim 5 , wherein 
 the temperature of the steel component undergoing induction heating is detected using a non-contact type temperature sensor.    
   
   
       7 . A heat treatment system comprising: a primary heat treatment device for heating a steel component at a temperature exceeding the A1 transformation point and then cooling the component to a temperature less than the A1 transformation point, thus forming a nitrogen enriched layer at the surface of the component; and a secondary heat treatment device for heating the steel component that has undergone primary heat treatment, at a temperature exceeding the A1 transformation point, and then cooling the component to a temperature less than the A1 transformation point, wherein the secondary heat treatment device conducts induction heating and die quenching.  
   
   
       8 . A heat treatment system comprising: a primary heat treatment device for heating a steel component at a temperature exceeding the A1 transformation point and then cooling the component to a temperature less than the A1 transformation point, thus forming a nitrogen enriched layer at the surface of the component, and a secondary heat treatment device for heating the steel component that has undergone primary heat treatment, at a temperature exceeding the A1 transformation point, and then cooling the component to a temperature less than the A1 transformation point, wherein a plurality of secondary heat treatment devices are disposed in parallel.  
   
   
       9 . A heat treatment system as claimed in  claim 8 , wherein induction heating is conducted within each of the secondary heat treatment devices.  
   
   
       10 . A heat treatment system as claimed in  claim 8 , wherein die quenching is conducted within each of the secondary treatment devices.  
   
   
       11 . A heat treatment system as claimed in  claim 1 , wherein 
 gas carbonitriding is conducted within the primary heat treatment device.    
   
   
       12 . A heat treatment system as claimed in  claim 5 , wherein 
 gas carbonitriding is conducted within the primary heat treatment device.    
   
   
       13 . A heat treatment system as claimed in  claim 7 , wherein 
 gas carbonitriding is conducted within the primary heat treatment device.    
   
   
       14 . A heat treatment system as claimed in  claim 8 , wherein 
 gas carbonitriding is conducted within the primary heat treatment device.    
   
   
       15 . A heat treatment system as claimed in  claim 3 , wherein 
 die quenching is conducted within the secondary treatment device.    
   
   
       16 . A heat treatment system as claimed in  claim 9 , wherein 
 die quenching is conducted within each of the secondary treatment devices.