Method for producing tubular coating-free press-hardened steel

Abstract

A method for producing a tubular component using a coating free press hardened steel (CFPHS) is provided. The method includes feeding a CFPHS continuous tubular component into a heating unit and heating the CFPHS continuous tubular component with the heating unit. The method then includes bending the CFPHS continuous tubular component using a bending unit before the continuous tubular component is cooled. After the bending step, the method includes cooling the CFPHS continuous tubular component using a cooling unit with ambient air.

What is claimed is: 
     
         1 . A method for producing a tubular component using a coating free press hardened steel (CFPHS), comprising:
 feeding a CFPHS continuous tubular component into a heating unit;   heating the CFPHS continuous tubular component with the heating unit;   bending the CFPHS continuous tubular component using a bending unit before the continuous tubular component is cooled; and   cooling the CFPHS continuous tubular component using a cooling unit with ambient air.   
     
     
         2 . The method of  claim 1 , wherein the heating unit includes at least one of an induction heating coil, a laser-based heater, or a flame-based heater. 
     
     
         3 . The method of  claim 1 , wherein the heating unit includes multiple induction heating coils arranged in series along the CFPHS continuous tubular component. 
     
     
         4 . The method of  claim 1 , wherein the heating unit includes multiple induction heating coils arranged in parallel along the CFPHS continuous tubular component. 
     
     
         5 . The method of  claim 1 , wherein the CFPHS continuous tubular component includes at least one of concentric CFPHS tubing or square CFPHS tubing. 
     
     
         6 . The method of  claim 1 , wherein heating the CFPHS continuous tubular component includes heating a portion of the CFPHS continuous tubular component with at least one induction heating coil to a uniform temperature. 
     
     
         7 . The method of  claim 1 , wherein heating the CFPHS continuous tubular component includes heating the CFPHS continuous tubular component to varying temperatures along a length of the CFPHS continuous tubular component to produce variable mechanical properties. 
     
     
         8 . The method of  claim 1 , wherein heating the CFPHS continuous tubular component includes heating the CFPHS continuous tubular component to varying temperatures along a circumference of the CFPHS continuous tubular component to produce variable mechanical properties. 
     
     
         9 . The method of  claim 1 , wherein heating the CFPHS continuous tubular component includes employing a variable heating rate to achieve a specific temperature profile. 
     
     
         10 . The method of  claim 1 , further comprising:
 soaking the CFPHS continuous tubular component for less than 30 seconds subsequent to heating the CFPHS continuous tubular component and before cooling the CFPHS continuous tubular component.   
     
     
         11 . The method of  claim 10 , further comprising:
 soaking the CFPHS continuous tubular component at a temperature between 875° C. and 1200° C. to produce a fully austenitized microstructure, subsequent to heating the CFPHS continuous tubular component and before cooling the CFPHS continuous tubular component.   
     
     
         12 . The method of  claim 10 , further including:
 soaking the CFPHS continuous tubular component at a temperature between 750° C. and 875° C., to achieve partial austenitization, subsequent to heating the CFPHS continuous tubular component and before cooling the CFPHS continuous tubular component.   
     
     
         13 . The method of  claim 1 , wherein bending the CFPHS continuous tubular component includes at least one of roll bending or mandrel bending. 
     
     
         14 . The method of  claim 1 , wherein cooling the CFPHS continuous tubular component includes using forced air cooling. 
     
     
         15 . The method of  claim 1 , wherein cooling the continuous tubular component includes using tunnel furnace cooling to retard a cooling rate. 
     
     
         16 . The method of  claim 1 , wherein cooling the continuous tubular component includes using a quenching media including cooled air. 
     
     
         17 . The method of  claim 1 , wherein the CFPHS continuous tubular component has a tube elongation of greater than 4% after cooling the CFPHS continuous tubular component. 
     
     
         18 . A method to achieve variable properties of a tubular component using a coating free press hardened steel (CFPHS), comprising:
 feeding a CFPHS continuous tubular component into a heating unit having induction heating coils;   energizing the induction heating coils using a variable power supply;   heating the CFPHS continuous tubular component by generating varying and localized current intensities within the heating unit and across the CFPHS continuous tubular component by operating predetermined ones of the induction heating coils;   bending the CFPHS continuous tubular component using a bending unit; and   cooling the CFPHS continuous tubular component using ambient air.   
     
     
         19 . The method of  claim 18 , further including:
 soaking the CFPHS continuous tubular component for less than 30 seconds subsequent to heating the CFPHS continuous tubular component and before cooling the CFPHS continuous tubular component.   
     
     
         20 . A method for producing induction-hardened tubular components using a coating free press hardened steel (CFPHS), comprising:
 feeding a CFPHS continuous tubular component into a heating unit having at least one induction heating coil;   heating the CFPHS continuous tubular component using the heating unit having at least one induction heating coil, wherein the at least one induction heating coil provides varying temperatures along a length of the CFPHS continuous tubular component to produce tailored properties;   soaking the CFPHS continuous tubular component between 875° C. and 1200° C. for less than 30 seconds to achieve a fully austenitized microstructure;   bending the CFPHS continuous tubular component using a bending unit before the CFPHS continuous tubular component is cooled, wherein the bending unit includes roll bending; and   cooling the CFPHS continuous tubular component using ambient air to transform the fully austenitized microstructure to martensite.