Method for Heat-Treating a Component Which Consists of a Metal Material and Comprises at Least One Surface Section Coated with a Glaze or Enamel Coating

Abstract

A method for heat-treating a component which consists of a metal alloy, in which or on which at least one surface section is coated with a glaze or enamel coating, includes heating the component to a heating temperature which at least equals a minimum quenching temperature, and quenching the component starting from a temperature which at least equals the minimum quenching temperature in order to produce a higher-strength microstructure in the component. The components can be heat-treated such that the glaze or enamel coating is reliably prevented from chipping. The glaze or enamel coating is pre-cooled to a pre-cooling temperature at least on its free surface prior to quenching, said pre-cooling temperature maximally corresponding to the temperature at which the glaze or enamel coating begins to soften, and wherein the cooling rate at which the glaze or enamel coating is cooled is lower than the cooling rate during quenching.

1 . A method for heat-treating a component which consists of a metal alloy, in which or on which at least one surface section is coated with a glaze or enamel coating, comprising:
 heating the component to a heating temperature, which at least equals a minimum quenching temperature, and   quenching the component starting from a temperature which at least equals the minimum quenching temperature, in order to produce a higher-strength microstructure in the component,   wherein the glaze or enamel coating is pre-cooled to a pre-cooling temperature at least on its free surface prior to quenching, said pre-cooling temperature maximally corresponding to the temperature at which the glaze or enamel coating begins to soften,   and wherein the cooling rate at which the glaze or enamel coating is pre-cooled, is lower than the cooling rate achieved during quenching.   
     
     
         2 . The method according to  claim 1 , wherein the glaze or enamel coating is pre-cooled to the pre-cooling temperature by passing a fluid across it. 
     
     
         3 . The method according to  claim 2 , wherein the fluid is a compressed air flow. 
     
     
         4 . The method according to  claim 2 , wherein the fluid is directed against the glaze or enamel coating by means of a nozzle device. 
     
     
         5 . The method according to  claim 1 , wherein the duration of the pre-cooling is set so that the temperature of the metal material of the component on the surface section which is coated with the glaze or enamel coating, at least equals the minimum quenching temperature. 
     
     
         6 . The method according to  claim 1 , wherein the cooling rate at which the glaze or enamel coating is pre-cooled, is lower than 5 K/s. 
     
     
         7 . The method according to  claim 1 , wherein the cooling rate, at which the glaze or enamel coating is pre-cooled, is at least 0.5 K/s. 
     
     
         8 . The method according to  claim 1 , wherein the cooling rate at which the component is quenched following pre-cooling of the glaze or enamel coating, is at least 5 K/s. 
     
     
         9 . The method according to  claim 1 , wherein the cooling rate at which the component is quenched following pre-cooling of the glaze or enamel coating, is a maximum of 50 K/s. 
     
     
         10 . The method according to  claim 1 , wherein the pre-cooling temperature is at least 30° C. lower than the minimum quenching temperature. 
     
     
         11 . The method according to  claim 10 , wherein the pre-cooling temperature is at least 50° C. lower than the minimum quenching temperature. 
     
     
         12 . The method according to  claim 1 , wherein the pre-cooling temperature is a maximum of 480° C. 
     
     
         13 . The method according to  claim 1 , wherein the metal material of the component is a light metal material. 
     
     
         14 . The method according to  claim 1 , wherein the component is a component for a combustion engine, in which at least one duct is provided, on which at least one surface section is coated with the glaze or enamel coating. 
     
     
         15 . The method according to  claim 1 , wherein the component is produced by casting. 
     
     
         16 . The method according to  claim 13 , wherein the metal material of the component is an aluminium-based material.