Rapid pre-heating to improve surface quality for coating-free press hardening steel components

Abstract

A method for manufacturing a coating-free press hardening steel (CFPHS) component comprises heating a CFPHS blank at a first predetermined heating rate to a first predetermined temperature in a first predetermined temperature range using a heater; transferring the CFPHS blank to a furnace; soaking the CFPHS blank in the furnace at a second predetermined temperature in a second predetermined temperature range for a predetermined period; and pressing and forming the CFPHS blank in a stamp/press to form a CFPHS component.

What is claimed is: 
     
         1 . A method for manufacturing a coating-free press hardening steel (CFPHS) component, comprising:
 heating a CFPHS blank at a first predetermined heating rate to a first predetermined temperature in a first predetermined temperature range using a heater;   transferring the CFPHS blank to a furnace;   soaking the CFPHS blank in the furnace at a second predetermined temperature in a second predetermined temperature range for a predetermined period; and   pressing and forming the CFPHS blank in a stamp/press to form a CFPHS component.   
     
     
         2 . The method of  claim 1 , wherein the first predetermined temperature is from 500° C. to 950° C. 
     
     
         3 . The method of  claim 1 , wherein the first predetermined heating rate is from 20° C./s to 300° C./s. 
     
     
         4 . The method of  claim 1 , wherein the heater is selected from a group consisting of an induction heater, a resistance heater, a laser heater, or combinations thereof. 
     
     
         5 . The method of  claim 1 , wherein the second predetermined temperature is from 750° C. to 1200° C. 
     
     
         6 . The method of  claim 1 , wherein the predetermined period is in a range from 5 s to 500 s. 
     
     
         7 . The method of  claim 1 , wherein the predetermined period is in a range from 5 s to 50 s. 
     
     
         8 . The method of  claim 1 , wherein, after pre-heating in the heater, the CFPHS component includes an oxidation layer having a thickness in a range from greater than or equal to 0.1 micron to less than or equal to 1.5 microns. 
     
     
         9 . The method of  claim 8 , wherein the oxidation layer covers greater than or equal to 90% of an exposed surface of the CFPHS component. 
     
     
         10 . The method of  claim 1 , wherein, after pre-heating in the heater, the CFPHS component includes an oxidation layer having a thickness in a range from greater than or equal to 0.1 micron to less than or equal to 1.0 microns. 
     
     
         11 . A method for manufacturing a coating-free press hardening steel (CFPHS) component, comprising:
 heating a CFPHS blank using a heater to a first predetermined temperature in a range from 500° C. to 950° C. at a first predetermined heating rate in a range from 20 to 300° C./s;   transferring the CFPHS blank to a furnace;   soaking the CFPHS blank in the furnace for a predetermined period at a second predetermined temperature in a range from 750° C. to 1200° C.; and   pressing and forming the CFPHS blank in a stamp/press to form a CFPHS component,   wherein, after pre-heating in the heater, the CFPHS component includes an oxidation layer having a thickness in a range from greater than or equal to 0.1 micron to less than or equal to 1.5 microns.   
     
     
         12 . The method of  claim 11 , wherein the heater is selected from a group consisting of an induction heater, a resistance heater, a laser heater, or combinations thereof. 
     
     
         13 . The method of  claim 11 , wherein the predetermined period is in a range from 5 s to 500 s. 
     
     
         14 . The method of  claim 11 , wherein the predetermined period is in a range from 5 s to 50 s. 
     
     
         15 . The method of  claim 11 , wherein the oxidation layer has a thickness in a range from greater than or equal to 0.1 micron to less than or equal to 1.0 microns. 
     
     
         16 . The method of  claim 11 , wherein the oxidation layer covers greater than or equal to 90% of an exposed surface of the CFPHS component. 
     
     
         17 . A method for manufacturing a coating-free press hardening steel (CFPHS) component, comprising:
 heating a CFPHS blank to a first predetermined temperature in a range from 500° C. to 950° C. at a first predetermined heating rate in a range from 20 to 300° C./s using one or more of induction heating, resistance heating, laser heating, or combinations thereof;   transferring the CFPHS blank to a furnace;   soaking the CFPHS blank in the furnace for a predetermined period in a range from 5 s to 50 s at a second predetermined temperature in a range from 750° C. to 1200° C.;   transferring the CFPHS blank to a stamp/press; and   pressing and forming the CFPHS blank in the stamp/press to form a CFPHS component,   wherein the CFPHS component includes an oxidation layer having a thickness in a range from greater than or equal to 0.1 micron to less than or equal to 1.5 microns.   
     
     
         18 . The method of  claim 17 , wherein the oxidation layer has a thickness in a range from greater than or equal to 0.1 micron to less than or equal to 1.0 microns. 
     
     
         19 . The method of  claim 17 , wherein the oxidation layer covers greater than or equal to 90% of an exposed surface of the CFPHS component.