Method and apparatus for forming ultrahigh tensile steel

Abstract

Disclosed is an apparatus and a method for forming an ultrahigh tensile steel. The method may include: (a) preparing a blank from a steel plate sheet; (b) cold-forming the blank into a shape corresponding to a desired end-product; (c) fixing the cold-formed materials to a plurality of pallets; (d) moving the pallets into a heating chamber, and heating the materials to a set temperature in the heating chamber; (e) moving the pallets into a cooling chamber, and cooling the materials in the cooling chamber; and (f) straightening dimensions of the materials which have been transformed in the heat treatment process and cooling process.

What is claimed is: 
     
         1 . A method for forming an ultrahigh tensile steel comprising:
 (a) preparing a blank cut from a steel plate sheet;   (b) cold-forming the blank to a shape corresponding to a desired end-product, to thereby form cold-formed materials;   (c) fixing the cold-formed materials to a plurality of pallets;   (d) moving the pallets into a heating chamber, and heating the cold-formed materials to a set temperature in the heating chamber, to thereby form heated materials;   (e) moving the pallets into a cooling chamber, and cooling the heated materials in the cooling chamber, to thereby form cooled materials; and   (f) straightening dimensions of the cooled materials.   
     
     
         2 . The method of  claim 1 , wherein
 in (b),   the blank is formed by s draw pressing, primary trimming, restriking, piercing, and secondary trimming sequentially through a plurality of molds.   
     
     
         3 . The method of  claim 2 , wherein the blank is cold-formed to the shape corresponding to the desired end-product by the plurality of molds within about 6 seconds. 
     
     
         4 . The method of  claim 1 , wherein
 in (c),   the cold-formed materials are fixed by a clamping unit disposed at the pallet.   
     
     
         5 . The method of  claim 1 , wherein
 in (d),   the cold-formed materials are heated until a temperature thereof reaches about 750-1000° C. in the heating chamber.   
     
     
         6 . The method of  claim 1 , wherein
 in (e),   the heated materials are cooled under a nitrogen atmosphere in the cooling chamber.   
     
     
         7 . The method of  claim 1 , wherein
 in (e),   a coolant is injected by a coolant injecting unit disposed at the pallet, and the heated materials are cooled by the coolant.   
     
     
         8 . The method of  claim 1 , wherein
 in (f),   the cooled materials are fixed to the straightening machine, and torsion straightening and cross-section straightening of the material are performed.   
     
     
         9 . An apparatus for forming ultrahigh tensile steel, comprising:
 a cold forming unit configured for cold-forming a blank cut from a steel plate sheet to a shape corresponding to a desired end-product, to thereby form cold-formed materials;   a plurality of pallets configured for fixing the cold-formed materials formed by the cold forming unit;   a heating chamber adapted to heat the cold-formed materials fixed to the pallets to a set temperature, to thereby form heated materials;   the cooling chamber adapted to cool the heated materials heated in the heating chamber, to thereby form cooled materials; and   a plurality of straightening machines configured for straightening one or more dimensions of the cooled materials after heating in the heating chamber and cooling in the cooling chamber.   
     
     
         10 . The apparatus of  claim 9 , wherein the cold forming unit comprises:
 a first mold configured for performing draw pressing of the blank,   a second mold configured for primarily trimming edges of the blank after the draw pressing,   a third mold configured for performing restriking of the blank after the primary trimming, and   a fourth mold configured for performing piercing and secondary trimming of the blank after the restriking.   
     
     
         11 . The apparatus of  claim 9 , wherein the pallet comprises:
 a supporting frame;   a plurality of storage plates mounted at the supporting frame and including a plurality of layers, and being configured for supporting the material; and   a plurality of clamp rods movably disposed to move along upward and downward directions by a plurality of clamping cylinders fixed to the supporting frame,   wherein a plurality of clamp fingers configured for supporting edges of the cold-formed material are integrally formed with the clamp rod.   
     
     
         12 . The apparatus of  claim 11 , wherein the pallet further comprises
 a coolant injecting unit disposed at the supporting frame, and configured for injecting a coolant to the cold-formed materials so as to cool the materials.   
     
     
         13 . The apparatus of  claim 12 , wherein the supporting frame comprises
 a plurality of vertical shafts configured for supporting each edge of the storage plate, and   a plurality of horizontal shafts connecting the vertical shafts to each other in a horizontal direction.   
     
     
         14 . The apparatus of  claim 13 , wherein the coolant injecting unit comprises:
 a coolant supply passage formed in the vertical shaft and the horizontal shaft, and providing communication between the vertical shaft and the horizontal shaft; and   injection nozzles mounted at the vertical shaft and the horizontal shaft, and in connection with the coolant supply passage so as to inject a coolant to the cold-formed material.   
     
     
         15 . The apparatus of  claim 9 , wherein the straightening machine comprises:
 a frame;   a clamping unit mounted at the frame, and configured for clamping the material;   a torsion straightening unit rotatably mounted at the frame in a state of gripping one end of the cold-formed material, and configured for performing torsion straightening to the cold-formed material; and   a plurality of cross-section straightening units at opposing sides with reference to the cold-formed material at the frame, and being rotatably mounted at the frame in a state of gripping flange portions formed at both sides of the cold-formed material, and configured for straightening a cross-section of flange portions of the cold-formed material.   
     
     
         16 . The apparatus of  claim 15 , wherein the clamping unit comprises at least one clamping body movably mounted along upward and downward directions by a clamping cylinder. 
     
     
         17 . The apparatus of  claim 15 , wherein the torsion straightening unit comprises:
 a rotating block rotatably mounted at the frame corresponding to the one end of the cold-formed material; and   a first gripper connected with the rotating block and movably mounted along upward and downward directions by a first operating cylinder, and configured for gripping the one end of the cold-formed material.   
     
     
         18 . The apparatus of  claim 17 , wherein the torsion straightening unit comprises a driving unit configured for rotating the rotating block, and
 the driving unit comprises a pinion gear coupled with a rotating shaft of the rotating block, a pair of rack bars coupled at an upper side and a lower side of the pinion gear, and a pair of second operating cylinders connected with the rack bars.   
     
     
         19 . The apparatus of  claim 15 , wherein the cross-section straightening unit comprises:
 a rotating body rotatably mounted at the frame at both sides with reference to the cold-formed material;   a third operating cylinder fixed to the frame, and hingedly coupled with the rotating body; and   a second gripper connected with the rotating body, and configured for gripping the flange portion of the cold-formed material.