Arrangement for gas quenching of heat-treated parts and method for carrying out same

Abstract

An arrangement for quenching structural components in a hot gas stream with which rapid cooling of the structural components to a holding temperature takes place at which transformation of the austenitic structure to bainite occurs. The control of the process can be carried out if a thermal buffer is disposed in the cooling gas stream.

1 . Arrangement for gas quenching heat-treated structural components with a quenching chamber for the batch-wise acceptance of the structural components, with a cooling gas circulation including a ventilator and connected to the quenching chamber, and a cooling device for the cooling of the cooling gas heated on the structural components as well as a measuring device for determining the temperature of the cooling gas at least at one site in the cooling gas circulation as well as a regulation device for the regulation of the cooling device, characterized in that a thermal buffer ( 11 ) is disposed in the circulation ( 3 ).  
   
   
       2 . Arrangement for gas quenching as claimed in  claim 1 , characterized in that a gas outlet ( 7 ) from the cooling gas circulation ( 3 ) is provided downstream of the quenching chamber ( 1 ) and a valve-controlled cooling gas intake connected to a gas supply for temperature-equalized gas is provided upstream of the quenching chamber ( 1 ).  
   
   
       3 . Arrangement for gas quenching as claimed in  claim 2 , characterized in that the thermal buffer ( 11 ) in the direction of flow is located ahead of the quenching chamber and following the cooling gas intake.  
   
   
       4 . Arrangement for gas quenching as claimed in  claim 2 , characterized in that the thermal buffer ( 11 ) in the direction of flow is disposed ahead of the cooling gas intake.  
   
   
       5 . Arrangement for gas quenching as claimed in  claim 3  or  4 , characterized in that the thermal buffer ( 11 ) in the direction is disposed following the outlet ( 7 ).  
   
   
       6 . Arrangement for gas quenching as claimed in one of the preceding claims, characterized in that parallel to the thermal buffer ( 11 ) is provided a parallel line ( 22 ) to the cooling gas circulation ( 3 ), in which a heat exchanger ( 24 ) is disposed.  
   
   
       7 . Arrangement for gas quenching as claimed in one of the preceding claims, characterized in that the thermal buffer ( 11 ) is a metallic structure with a large surface and with a high thermal mass relative to the circulated gas stream.  
   
   
       8 . Arrangement for gas quenching as claimed in one of the preceding claims, characterized in that a heating means ( 10 ) is disposed in the cooling gas circulation ( 3 ) ahead of the thermal buffer ( 11 ).  
   
   
       9 . Arrangement as claimed in one of the preceding claims, characterized in that the gas supply is comprised of a first supply tank ( 13 ) with heated gas, of a second supply tank ( 14 ) with gas at ambient temperature and of a third supply tank ( 16 ) with an intensively cooled gas.  
   
   
       10 . Method for gas quenching structural components in a quenching chamber with a cooling gas, wherein the structural components, after their rapid cooling to holding temperature, are kept for a certain length of time at this holding temperature in order to make possible a structural transformation, and wherein the cooling gas is circulated in a cooling gas circulation including a ventilator and connected to the quenching chamber, characterized in that for cooling the cooling gas heated on the structural components an additional cooling gas is introduced into the cooling circulation, such that a temperature obtains which corresponds to the projected holding temperature.  
   
   
       11 . Method for the gas quenching as claimed in  claim 10 , characterized in that in the circulation ( 3 ) a thermal buffer ( 11 ) is located which, before the start of the quenching, is heated to holding temperature.