Method for producing a component by reshaping a plate, and device for carrying out said method

Abstract

The invention relates to a method for producing a component by reshaping a coated plate consisting of tempering steel, said plate being austenitized before the reshaping by means of a first heat treatment, followed by the growth of the layer thickness. The aim of the invention is to optimize the process and to prevent the production of scrap plates caused by interruptions to the process. To this end, after being rapidly cooled, the heat-treated plate is temporarily stored, and is briefly heated again to the austenitization temperature, directly before being reshaped to form the component. Once the structure has been modified, the plate is reshaped and hardened. Preferably, the plate is heated a second time by induction.

1 . A method for producing a component by reshaping a coated plate of quenched and tempered steel, before reshaping in a first process step, the plate being supplied to a first furnace and being austenitized there and a residence time of the plate in the first furnace being chosen such that in addition to the structure transformation an increase in the layer thickness takes place, the method comprising: 
 rapid cooling and subsequent intermediate storage of a heat treated sheet bar,    repeated, brief heating of the sheet bar in a second furnace to an austenitization temperature directly prior to forming into the component, and    forming and hardening the sheet bar after completed structure transformation.    
   
   
       2 . The method as claimed in  claim 1 , wherein the residence time in the first furnace is between nine minutes and thirty minutes.  
   
   
       3 . The method as claimed in  claim 1 , wherein when the sheet bar is heated again to an austenitization temperature in the second furnace, such that only one structure transformation takes place, but no longer an increase of layer thickness.  
   
   
       4 . The method as claimed in  claim 3 , wherein a residence time of the sheet bar in the second furnace is from ten seconds to two and one half minutes.  
   
   
       5 . The method as claimed in  claim 1 , wherein the sheet bar is heated in the first furnace by electricity or gas, while heating in the second furnace takes place by induction.  
   
   
       6 . The method as claimed in  claim 1 , wherein the first heating takes place at a steel or sheet manufacturer, while the second heat treatment takes place at a processing company.  
   
   
       7 . The method as claimed in  claim 1 , wherein during the second heat treatment the sheet bar is heated to different temperatures over its surface.  
   
   
       8 . The method as claimed in  claim 1 , wherein the sheet bar, before reheating in the second furnace, is locally reinforced by applying at least one reinforcing sheet.  
   
   
       9 . The process as claimed in  claim 1 , wherein the sheet bar is a tailored blank.  
   
   
       10 . A device for carrying out the process of  claim 1 , the device comprising: 
 a tool for producing sheet bars from a coil,    a first furnace for initial heat treatment including inducing an increase in the layer thickness of the sheet bars,    a cooling zone for the sheet bars,    an intermediate storage area for the sheet bars,    a second furnace for repeated heat treatment of the sheet bars,    a forming/tempering tool with a press means and a cooling device,    a trimming device for producing a trimmed finish contour and holes.    
   
   
       11 . The device as claimed in  claim 10 , wherein the first furnace is an electricity-based and/or gas-based furnace ( 7 ), and the second furnace is an induction furnace.  
   
   
       12 . The device as claimed in  claim 11 , wherein an inductor is integrated into the transport device which is located between the intermediate storage and the forming/tempering tool.  
   
   
       13 . The device as claimed in  claim 10 , further comprising a station for applying at least one reinforcing sheet to the sheet bar between the cooling zone and the second furnace.  
   
   
       14 . The method of  claim 1  wherein the plate is an aluminum-coated plate.  
   
   
       15 . A method of producing a component comprising: 
 providing a coated sheet of quenched and tempered steel;    shaping the sheet;    heat treating the shaped sheet to perform a first austenitization of the sheet, during which a structure transformation occurs increasing the layer thickness thereof;    cooling and quenching the heat treated sheet;    storing the cooled and quenched sheet;    performing a second heat treatment to perform a second austenitization of the sheet; and    forming the sheet into the component.    
   
   
       16 . The method of  claim 15  wherein the first heat treatment is performed in a gas or electric furnace and/or the second heat treatment is performed in an induction furnace.  
   
   
       17 . The method of  claim 15 , further comprising reinforcing the sheet between the heat treatment steps.  
   
   
       18 . The method of  claim 15  wherein the first heat treatment comprises a residence time of between approximately 9 and 30 minutes.  
   
   
       19 . The method of  claim 15  wherein second heat treatment comprises a residence time of between approximately 10 seconds to two minutes.  
   
   
       20 . The method of  claim 15  wherein during the second heat treatment step, no change in thickness of the sheet occurs.  
   
   
       21 . The method of  claim 15  wherein the sheet has a martensitic structure following the forming step.  
   
   
       22 . The method of  claim 15 , further comprising transporting the sheet from a first location, where the first heat treatment is performed.  
   
   
       23 . The method of  claim 22  wherein the second heat treatment is performed during the transporting.  
   
   
       24 . The method of  claim 15  wherein the second heat treatment comprises heating the sheet to different intensities at different locations thereof.  
   
   
       25 . A product produced by the method of  claim 15.