Stress-relief heat treatment apparatus

Abstract

A stress-relief heat treatment apparatus according to the present invention for stress-relief heat-treating a rail which is welded includes an induction heating coil, and the induction heating coil is arranged at a lateral lace of a web of the rail while being separated from a welding center of the rail by 20 mm to 300 mm in a longitudinal direction of the rail. The stress-relief heat treatment apparatus may include a plurality of the induction heating coils, and the induction heating coils may be arranged at both sides of the welding center. The stress-relief heat treatment apparatus may include a plurality of the induction heating coils, an axial direction of the induction heating coil may be vertical to a lateral surface of the rail and a plurality of the induction heating coils, of which distances from the welding center along the longitudinal direction of the rail are the same, may be arranged to cover a whole circumference of the rail while being separated from each other.

1 . A stress-relief heat treatment apparatus for stress-relief heat-treating a rail which is welded, the stress-relief heat treatment apparatus comprising:
 an induction heating coil, wherein   the induction heating coil is arranged at a lateral face of a web of the rail while being separated from a welding center of the rail by 20 mm to 300 mm in a longitudinal direction of the rail.   
     
     
         2 . The stress-relief heat treatment apparatus according to  claim 1 , wherein
 the stress-relief heat treatment apparatus includes a plurality of the induction heating coils, and   the induction heating coils are arranged at both sides of the welding center along the longitudinal direction of the rail.   
     
     
         3 . The stress-relief heat treatment apparatus according to  claim 1 , wherein
 the stress-relief heat treatment apparatus includes a plurality of the induction heating coils,   an axial direction of the induction heating coil which is arranged at the rail is vertical to a surface of the rail, and   a plurality of the induction heating coils, of which distances from the welding center along the longitudinal direction of the rail are the same, are arranged to cover a whole circumference of the rail while being separated from each other.   
     
     
         4 . The stress-relief heat treatment apparatus according to  claim 1 , wherein
 an axial direction of the induction heating coil which is arranged at the rail is parallel to the longitudinal direction of the rail, and   the induction heating coil is arranged to cover a whole circumference of the rail.   
     
     
         5 . The stress-relief heat treatment apparatus according to  claim 4 , wherein
 the induction heating coil is arranged at both sides of the welding center along the longitudinal direction of the rail, and   a direction of a current flowing in the induction heating coil arranged at one side of the welding center and a direction of a current flowing in the induction heating coil arranged at the other side of the welding center are opposite to each other.   
     
     
         6 . (canceled) 
     
     
         7 . (canceled) 
     
     
         8 . (canceled) 
     
     
         9 . The stress-relief heat treatment apparatus according to  claim 5 , further comprising a high-frequency power source, wherein
 the high-frequency power source is configured to flow the current with a direction of the current flowing in the induction heating coil arranged at one side of the welding center and a direction of a current flowing in the induction heating coil arranged at the other side of the welding center being opposite to each other.   
     
     
         10 . The stress-relief heat treatment apparatus according to  claim 2 , wherein
 the stress-relief heat treatment apparatus includes a plurality of the induction heating coils,   an axial direction of the induction heating coil which is arranged at the rail is vertical to a surface of the rail, and   a plurality of the induction heating coils, of which distances from the welding center along the longitudinal direction of the rail are the same, are arranged to cover a whole circumference of the rail while being separated from each other.   
     
     
         11 . The stress-relief heat treatment apparatus according to  claim 2 , wherein
 an axial direction of the induction heating coil which is arranged at the rail is parallel to the longitudinal direction of the rail, and   the induction heating coil is arranged to cover a whole circumference of the rail.   
     
     
         12 . The stress-relief heat treatment apparatus according to  claim 11 , wherein
 the induction heating coil is arranged at both sides of the welding center along the longitudinal direction of the rail, and   a direction of a current flowing in the induction heating coil arranged at one side of the welding center and a direction of a current flowing in the induction heating coil arranged at the other side of the welding center are opposite to each other.   
     
     
         13 . The stress-relief heat treatment apparatus according to  claim 12 , further comprising a high-frequency power source, wherein
 the high-frequency power source is configured to flow the current with a direction of the current flowing in the induction heating coil arranged at one side of the welding center and a direction of a current flowing in the induction heating coil arranged at the other side of the welding center being opposite to each other.   
     
     
         14 . The stress-relief heat treatment apparatus according to any one of  claims 1  to  13 , wherein
 a plurality of the induction heating coils, of which the distances from the welding center along the longitudinal direction of the rail are different to each other, are arranged while being separated from each other at one side or both sides of the welding center. 
 
     
     
         15 . The stress-relief heat treatment apparatus according to any one of  claims 1  to  13 , wherein
 a number of turns of the induction heating coil is two or more. 
 
     
     
         16 . The stress-relief heat treatment apparatus according to  claim 14 , wherein
 a number of turns of the induction heating coil is two or more.   
     
     
         17 . The stress-relief heat treatment apparatus according to any one of  claims 1  to  13 , wherein
 a frequency of the current flowing in the induction heating coil is 1 kHz to 20 kHz. 
 
     
     
         18 . The stress-relief heat treatment apparatus according to  claim 14 , wherein
 a frequency of the current flowing in the induction heating coil is 1 kHz to 20 kHz.   
     
     
         19 . The stress-relief heat treatment apparatus according to  claim 16 , wherein
 a frequency of the current flowing in the induction heating coil is 1 kHz to 20 kHz.   
     
     
         20 . The stress-relief heat treatment apparatus according to  claim 17 , further comprising a high-frequency power source, wherein
 the high-frequency power source is configured to flow the current with the frequency of the current flowing in the induction heating coil being 1 kHz to 20 kHz.   
     
     
         21 . The stress-relief heat treatment apparatus according to  claim 18 , further comprising a high-frequency power source, wherein
 the high-frequency power source is configured to flow the current with the frequency of the current flowing in the induction heating coil being 1 kHz to 20 kHz.   
     
     
         22 . The stress-relief heat treatment apparatus according to  claim 19 , further comprising a high-frequency power source, wherein
 the high-frequency power source is configured to flow the current with the frequency of the current flowing in the induction heating coil being 1 kHz to 20 kHz.