Device and method for providing a selective heat treatment on a metal sheet

Abstract

A device for providing selective heat treatment on a metal sheet comprising boron steel is provided. The device comprises a laser source for emitting a laser beam onto the metal sheet to provide a selective heat treatment thereon, wherein a defined heat treated grid pattern is formed on the metal sheet by the selective heat treatment. The device further comprises a control unit arranged to control the operation of the laser source for providing the defined heat treated pattern onto the metal sheet; and control the case hardness depth of the defined heat treated pattern based on a temperature parameter and a holding time parameter associated with the operation of the laser source. A method for performing controlling the case hardness depth of a selectively heat treated metal sheet of boron steel is also provided.

1 . A device for providing selective heat treatment on a metal sheet comprising boron steel, comprising
 a laser source for emitting a laser beam onto the metal sheet to provide a selective heat treatment thereon, wherein a defined heat treated pattern is formed on the metal sheet by the selective heat treatment; and   a control unit arranged to:   control the operation of the laser source for providing the defined heat treated pattern onto the metal; and   control the case hardness depth of the defined heat treated pattern based on a temperature parameter and a holding time parameter associated with the operation of the laser source.   
     
     
         2 . The device according to  claim 1 , wherein the control unit is further arranged to control the case hardness depth based on receipt of an input signal comprising information associated with a desired case hardness depth of the defined heat treated pattern. 
     
     
         3 . The device according to  claim 2 , wherein the control unit, upon receipt of said input signal, is arranged to adapt at least one of the temperature parameter or the holding time parameter by adapting the laser speed or sheet movement speed. 
     
     
         4 . The device according to  claim 1 , wherein the control unit, upon receipt of said input signal, is further arranged to control the depth of the case of the metal sheet by adapting the power of the laser source. 
     
     
         5 . The device according to  claim 1 , wherein the temperature parameter determines a temperature range for the treated metal sheet grid pattern during the selective heat treatment. 
     
     
         6 . The device according to  claim 1 , wherein the holding time parameter determines a time period during which each metal sheet portion of the defined heat treated pattern is above a predefined temperature. 
     
     
         7 . The device according to  claim 1 , wherein the selective heat treatment is applied to a first surface of the metal sheet, which first surface is selected to coincide with an inner surface after forming or shaping the metal sheet. 
     
     
         8 . The device according to  claim 1 , wherein the temperature parameter relates to a temperature value range between a transition temperature for the metal sheet and below a melting temperature of the metal sheet. 
     
     
         9 . The device according to  claim 1 , wherein the laser beam has a circular spot shape resulting from a Gaussian distribution setting on the laser source. 
     
     
         10 . The device according to  claim 9 , wherein the control unit, upon receipt of the input signal, is further arranged to control case hardness depth by adapting the circular laser focus to a square shaped laser beam spot shape by selecting a uniform distribution setting for the laser source. 
     
     
         11 . The device according to  claim 1 , wherein the laser source is a carbon dioxide laser or a fiber laser. 
     
     
         12 . A method for providing a defined heat treated pattern on a metal sheet comprising boron steel, the method comprising
 emitting a laser beam onto the metal sheet to provide the selective heat treatment thereon;   controlling the operation of the laser source for providing the defined heat treated pattern onto the metal sheet; and   controlling the case hardness depth of the defined heat treated pattern based on a temperature parameter and a holding time parameter associated with the operation of the laser source.   
     
     
         13 . The method according to  claim 12 , further comprising
 controlling the case hardness depth based on receipt of an input signal comprising information associated with a desired case hardness depth of the defined heat treated pattern.   
     
     
         14 . The method according to  claim 13 , further comprising, upon receipt of said input signal,
 adapting at least one of the temperature parameter or the holding time parameter by adapting the laser speed and/or the sheet metal movement speed.   
     
     
         15 . The method according to  claim 12 , further comprising, upon receipt of said input signal,
 controlling the depth of the case of the metal sheet by adapting the power of the laser source.   
     
     
         16 . The method according to  claim 12 , wherein the temperature parameter determines a temperature range for the treated metal sheet grid pattern during the selective heat treatment. 
     
     
         17 . The method according to  claim 12 , wherein the holding time parameter determines a time period during which each metal sheet portion of the defined heat treated pattern is above a predefined temperature. 
     
     
         18 . The method according to  claim 12 , wherein the selective heat treatment is applied to a first surface of the metal sheet, which first surface is selected to coincide with an inner surface after forming or shaping the metal sheet. 
     
     
         19 . The method according to  claim 12 , wherein the laser beam has a circular spot shape resulting from a Gaussian distribution setting on the laser source. 
     
     
         20 . The method according to  claim 19 , wherein the control unit, upon receipt of the input signal, further controls the case hardness depth by adapting the circular laser focus to a square shaped laser beam spot shape by selecting a uniform distribution setting for the laser source. 
     
     
         21 . The method according to  claim 12 , wherein the laser source is a carbon dioxide laser or a fiber laser.