Gas quenching cell for steel parts

Abstract

A method for quenching a steel load by flowing of a gas at the load level via gas moving means. The moving means are controlled to have the gas flow at the load level at a speed which varies according to a speed profile, at least a portion of which comprises, successively, a plateau at a first speed and a plateau at a second speed greater than the first speed.

1 . A method for quenching a steel load ( 14 ) by flowing of a gas at the level of the load via gas moving means ( 18 ,  20 ), wherein the moving means are controlled to have the gas flow at the load level at a speed which varies according to a speed profile, at least a portion of which comprises, successively, a plateau at a first speed ( 44 ;  62 ) and a plateau at a second speed ( 46 ;  64 ) greater than the first speed.  
   
   
       2 . The method of  claim 1 , wherein the gas, after having flowed at the level of the load ( 14 ), is cooled down by a exchanger ( 22 ) in which flows a cooling fluid, the moving means being controlled to have the gas flow at the level of the load ( 14 ) from the plateau at the first speed ( 44 ;  62 ) to the plateau at the second speed ( 46 ;  64 ) when the temperature of the cooling fluid reaches a given threshold temperature.  
   
   
       3 . The method of  claim 1 , wherein the static pressure of the gas at the level of the load ( 14 ) is decreased during the plateau at the first speed ( 46 ;  64 ) with respect to the plateau at the second speed ( 44 ;  62 ).  
   
   
       4 . The method of  claim 1 , wherein the gas, after having flowed at the level of the load ( 14 ), is cooled down by an exchanger ( 22 ) in which flows a cooling fluid, the moving means ( 18 ,  20 ) being controlled to have the gas flow at the load level according to a speed profile successively comprising a first plateau at the second speed ( 42 ), a plateau at the first speed ( 44 ) and a second plateau at the second speed, the transition between the first plateau at the second speed ( 46 ) and the plateau at the first speed being performed during an increase phase of the cooling fluid temperature.  
   
   
       5 . The method of  claim 4 , wherein the moving means are controlled to have the gas flow at the level of the load ( 14 ) from the first plateau at the second speed ( 42 ) to the plateau at the first speed ( 44 ) when the cooling fluid temperature exceeds a given threshold temperature.  
   
   
       6 . The method of  claim 4 , wherein the moving means are controlled to have the gas flow at the level of the load ( 14 ) from the plateau at the first speed ( 44 ) to the second plateau at the second speed ( 46 ) when the cooling fluid temperature decreases under a given additional threshold temperature.  
   
   
       7 . The method of  claim 4 , wherein the moving means are controlled to have the gas flow at the level of the load ( 14 ) from the first plateau at the second speed ( 42 ) to the plateau at the first speed ( 44 ) after a determined time.  
   
   
       8 . The method of  claim 1 , wherein the gas, after having flowed at the level of the load ( 14 ), is cooled down by a exchanger ( 22 ) in which flows a cooling fluid, the moving means ( 18 ,  20 ) being controlled to have the gas flow at the load level according to a speed profile comprising, from the beginning of a quenching operation, successively a plateau at the first speed ( 62 ) and a plateau at the second speed ( 64 ), the transition between the plateau at the first speed and the plateau at the second speed being performed during an increase phase of the cooling fluid temperature.  
   
   
       9 . The method of  claim 8 , wherein the moving means are controlled to have the gas flow at the level of the load ( 14 ) from the plateau at the first speed ( 62 ) to the plateau at the second speed ( 64 ) after a determined time.  
   
   
       10 . A gas quenching cell of a load ( 14 ) comprising a stirring element ( 20 ) driven by a motor ( 18 ) to cause a gas flow between the load and an exchanger ( 22 ), comprising means capable of varying the stirring element drive speed to have the gas flow at the load level at a speed which varies according to a speed profile comprising at least successively a plateau at a first speed ( 44 ;  62 ) and a plateau at a second speed ( 46 ;  64 ) greater than the first speed.