Apparatus and method for preparing hot stamped part

Abstract

A method for mass preparing hot stamped parts is disclosed, it includes: feeding a blank into an airtight feeding chamber and then pumping the feeding chamber to a certain vacuum; feeding the blank to an airtight heating chamber for austenitizing heating to obtain a hot blank; feeding the hot blank to an airtight discharging chamber; and transferring the blank conveyed from the discharging chamber to the stamping press for hot stamping forming. By using the method, especially an aluminum-silicon coated blank is subjected to airtight heat treatment and hot stamping by the stamping press, high-strength aluminum-silicon coated parts produced have obviously less hydrogen content than high-strength aluminum-silicon coated parts produced by a traditional atmosphere furnace, which is with less risk of hydrogen embrittlement and is particularly suitable for hot formed aluminum-silicon coated parts with strength of more than or equal to 1500 MPa.

1 . A method for mass preparing hot stamped parts, wherein the method functions in preparation by adopting an apparatus for mass preparing hot stamped parts and the method comprises:
 feeding a blank into a feeding chamber which is airtight and then pumping the feeding chamber to a certain vacuum;   feeding the blank to a heating chamber which is airtight for austenitizing heating to obtain a hot blank;   feeding the hot blank to a discharging chamber which is airtight; and   transferring the blank conveyed from the discharging chamber to a stamping press for hot stamping forming.   
     
     
         2 . The method according to  claim 1 , wherein the apparatus comprises:
 a heating furnace unit and a hot stamping unit; wherein   the heating furnace unit is provided with a plurality of independent airtight chambers, comprising the feeding chamber, the heating chamber and the discharging chamber which are communicated in sequence; the hot stamping unit comprises the stamping press;   the discharging chamber is communicated with the stamping press;   wherein an airtight feeding furnace door is provided at an inlet of the feeding chamber, and a first airtight isolation furnace door is provided between an outlet of the feeding chamber and the inlet of the heating chamber; and   wherein an airtight discharging furnace door is provided at an outlet of the discharging chamber, and a second airtight isolation furnace door is provided between an inlet of the discharging chamber and an outlet of the heating chamber.   
     
     
         3 . The method according to  claim 2 , wherein the blank is fed into the feeding chamber through the feed furnace door; the blank in the feeding chamber is fed to the heating chamber through the first isolation furnace door; the hot blank in the heating chamber is fed to the discharging chamber through the second isolation furnace door; and the blank in the discharging chamber is fed to the stamping press through the discharging furnace door. 
     
     
         4 . The method according to  claim 2 , wherein the blank comprises an aluminum-silicon coated blank. 
     
     
         5 . The method according to  claim 3 , wherein when the heating chamber is a vacuum chamber, after the blank enters the feeding chamber through the feeding furnace door, the feeding chamber is pumped to a vacuum higher than 10000 Pa; and
 after vacuum in the feeding chamber is close to the vacuum in the heating chamber, the first isolation furnace door between the feeding chamber and the heating chamber is opened, and the blank is fed into the heating chamber for austenitizing heating, and then the first isolation furnace door between the feeding chamber and the heating chamber is closed.   
     
     
         6 . The method according to  claim 3 , wherein when the heating chamber is a vacuum chamber, the discharging chamber is pumped to a vacuum higher than 10000 Pa before heat treatment in the heating chamber is completed and the blank is ready to be discharged;
 after the vacuum in the discharging chamber is close to the vacuum in the heating chamber, the second isolation furnace door between the discharging chamber and the heating chamber is opened, and the blank is fed into the discharging chamber, and then the second isolation furnace door between the discharging chamber and the heating chamber is closed; and   before the discharging furnace door of the discharging chamber is opened, dry air or other dry gas is filled into the discharging chamber to reach the outdoor air pressure, and then the discharging furnace door is opened.   
     
     
         7 . The method according to  claim 3 , wherein when the heating chamber is a dry atmosphere chamber, after the blank enters the feeding chamber through the feeding furnace door, the feeding chamber is pumped to a vacuum higher than 10000 Pa;
 then dry air or other dry gas is introduced into the feeding chamber, and water vapor content of the dry air or other dry gas is lower than 1000 ppm; and   after an air pressure in the feeding chamber is close to an air pressure in the heating chamber, the first isolation furnace door between the feeding chamber and the heating chamber is opened, and the blank is fed into the heating chamber for austenitizing heating, and then the first isolation furnace door between the feeding chamber and the heating chamber is closed.   
     
     
         8 . The method according to  claim 3 , wherein when the heating chamber is a vacuum chamber, the discharging chamber is pumped to a vacuum higher than 10000 Pa before the heat treatment in the heating chamber is completed and the blank is ready to be discharged; then dry air or other dry gas is introduced into the discharging chamber, water vapor content of the dry air or other dry gas is lower than 1000 ppm;
 after an air pressure in the discharging chamber is close to an air pressure in the heating chamber, the second isolation furnace door between the discharging chamber and the heating chamber is opened, and the blank is fed into the discharging chamber, and then the second isolation furnace door between the discharging chamber and the heating chamber is closed;   before the discharging furnace door of the discharging chamber is opened, dry air or other dry gas is filled into the discharging chamber to reach the outdoor air pressure, and then the discharging furnace door is opened.   
     
     
         9 . The method according to  claim 1 , wherein a method for the hot stamping forming comprises laser welding the discharged blank. 
     
     
         10 . The method according to  claim 1 , wherein a blank temperature for the hot stamping forming is controlled within a range of 500° C. to 700° C., and a heating rate of the hot stamping forming is less than 7° C./s. 
     
     
         11 . The method according to  claim 2 , wherein the heating chamber is selected from a vacuum chamber or an atmosphere chamber. 
     
     
         12 . The method according to  claim 11 , wherein when the heating chamber is the vacuum chamber, a vacuum in the heating chamber is 1 Pa to 10000 Pa, and a temperature in the heating chamber is 880° C. to 1000° C.; and the heating chamber is configured to heat multiple groups of blanks at a same time. 
     
     
         13 . The method according to  claim 11 , wherein when the heating chamber is the atmosphere chamber, the atmosphere in the heating chamber is a dry air, and a water vapor content of the dry air is less than 1000 ppm; an air pressure in the heating chamber is equal to an atmospheric pressure, and a temperature in the heating chamber is 880° C. to 1000° C.; and the heating chamber is configured to heat multiple groups of blanks at a same time. 
     
     
         14 . The method according to  claim 2 , wherein a temperature in the discharging chamber is 400° C. to 800° C. 
     
     
         15 . The method according to  claim 2 , wherein a feeding platform is provided upstream of the feeding chamber, and a discharging platform is provided downstream of the discharging chamber. 
     
     
         16 . The method according to  claim 2 , wherein a production cycle of the hot stamped parts is between 20 s to 40 s. 
     
     
         17 . The method according to  claim 16 , wherein the production cycle of the hot stamped parts is between 20 s to 30 s. 
     
     
         18 . The method according to  claim 2 , wherein a time from the heating chamber to the stamping press is not more than 12 s. 
     
     
         19 . The method according to  claim 18 , wherein the time from the heating chamber to the stamping press is not more than 10 s. 
     
     
         20 . The method according to  claim 4 , wherein a tensile strength of the aluminum-silicon coated blank ranges from 1300 Mpa to 2200 Mpa.