Metallic member forming method

Abstract

A metallic member forming method capable of achieving both formability of a metallic member and highly strengthening same. Cylindrical metallic member 1 having a hollow space 10 and forming die 3 having a forming face 31 are used. Metallic member 1 is heated up to a temperature range capable of quench-reinforcing (e.g., not less than A1 transformation point). By increasing internal pressure of gas contained in the hollow space 10 of the metallic member 1 a wall 1 a of the metallic member 1 is bulged and/or deformed, and the bulged, deformed wall 1 a of the metallic member 1 is deformed by bringing it into intimate contact with the forming face 31 of the forming die concurrently with quench-reinforcing it. High strengthening of the metallic member 1 is achieved.

What is claimed is:  
     
         1 . A method for forming metallic member comprising: 
 providing a metallic member having a hollow space and a forming die having a forming face; and    performing a forming and quench-reinforcing step by increasing an internal pressure of gas contained in the hollow space of said metallic member heated up to a temperature range capable of quench-reinforcing to bulge and/or deform said metallic member's wall, wherein forming of the bulged and/or deformed wall is performed by bringing the same into intimate contact with the forming face of said forming die accompanied by simultaneous quench-reinforcing of said wall.    
     
     
         2 . The method as defined in  claim 1 , wherein said increasing of said internal pressure of gas contained in the hollow space of said metallic member is performed by feeding a gas into the hollow space of said metallic member.  
     
     
         3 . The method as defined in  claim 1 , wherein heating said metallic member is performed by at least one operation selected from the group consisting of operation for maintaining said metallic member in a furnace chamber of a heating furnace, induction heating operation for induction-heating said metallic member, and resistance heating operation for energizing said metallic member.  
     
     
         4 . The method as defined in  claim 3 , wherein said operation for maintaining said metallic member in the furnace chamber of said furnace is performed under the condition that the furnace chamber of said furnace has a non-oxidizing atmosphere  
     
     
         5 . The method as defined in  claim 3 , wherein said induction heating operation is performed by applying an alternating current to an electrically conductive member for induction heating in a state of placing said electrically conductive member in proximity of said metallic member disposed within said forming die to induction-heat said metallic member.  
     
     
         6 . The method as defined in  claim 3 , wherein said resistance heating operation is performed by energizing said metallic member from energizing terminals in a state of connecting said energizing terminals to said metallic member disposed within said forming die to heat said metallic member by Joule heat.  
     
     
         7 . The method as defined in  claim 1 , wherein said metallic member is made of an iron-based material, a titanium-based material, an aluminum-based material or a cupper-based material.  
     
     
         8 . The method as claimed in  claim 1 , wherein said metallic member is made of an iron-based material and heated up to a temperature of not less than Al transformation point, and said forming and quench-reinforcing step comprises bringing the wall of said metallic member into intimate contact with the forming face of said forming die to harden at least a part of said metallic member.  
     
     
         9 . The method as defined in  claim 1 , wherein said forming die has a cooling device for cooling said forming die at least a part thereof corresponding to a part of said metallic member to be quench-hardened.  
     
     
         10 . The method as defined in  claim 1 , wherein said gas to be fed into the hollow space of said metallic member is at least one selected from the group consisting of air, nitrogen gas, nitrogen-rich gas, argon gas and argon-rich gas.  
     
     
         11 . The method as defined in  claim 2 , wherein an operation for feeding gas into the hollow space of said metallic member is performed from a high-pressure gas supply source capable of feeding high pressure gas.  
     
     
         12 . The method as defined in  claim 1 , wherein said metallic member has at least one opening communicating with said hollow space and formed by a tapered open wall face, and wherein said opening is sealed by applying directly or indirectly a sealant, which has a slant corresponding to that of the tapered open wall face of said metallic member, to the tapered open wall face of said metallic member.  
     
     
         13 . A method for forming metallic member comprising the steps of: 
 (a) placing a metallic member having a hollow space in a forming die assembly,    (b) heating said metallic member placed in the forming die assembly,    (c) bringing a prescribed surface of said metallic member into intimate contact with a prescribed face of the forming die assembly by introducing a pressured gas into said hollow space of the metallic member heated in the forming die assembly, to thereby plastically deform said metallic member, and,    (d) quenching said metallic member immediately following the deformation of the metallic member through cooling said metallic member in a state of being placed in the forming die assembly.    
     
     
         14 . The method as defined in  claim 13 , wherein said heating of step (b) is performed within an opened space of the forming die assembly.  
     
     
         15 . The method as defined in  claim 13 , wherein said heating step (b) is performed under a thermally insulated condition within an opened space of the forming die assembly.  
     
     
         16 . The method as defined in  claim 15 , wherein said thermally insulated condition is provided by a thermal insulator intervening between the die and the metallic member, said insulator being removed before closing the die assembly.  
     
     
         17 . The method as defined in  claim 13 , wherein said heating step (b) is carried out by induction heating by an induction conductor disposed within the hollow space of the metallic member.  
     
     
         18 . A method for forming metallic member comprising the steps of: 
 (a) heating a cylindrical metallic member having a hollow space,    (b) placing said heated metallic member into a forming die assembly,    (c) bringing said heated metallic member into intimate contact with a prescribed face of the forming die assembly by introducing a pressurized gas into the hollow space of said metallic member, to thereby plastically deform said metallic member,    (d) quenching said metallic member immediately following the deformation of said metallic member through cooling said forming die assembly, in a state that said metallic member is placed in the forming die assembly.    
     
     
         19 . A metallic member product produced according to the method as defined in  claim 1 .  
     
     
         20 . An apparatus for forming metallic member comprising: 
 a forming die assembly for placing a cylindrical metallic member having a hollow space into a cavity of the forming die assembly,    a gas supply device for supplying a pressurized gas into the hollow space of said metallic member heated within the forming die assembly,    a cooling device for cooling said forming die assembly configured to quench-hardening said metallic member placed and plastically deformed in said forming die assembly, and    a control unit for controlling said gas supply device so as to perform bulging and/or deforming of said metallic member together with quench-hardening the same.    
     
     
         21 . The apparatus as defined in  claim 20 , comprising a heating device for selectively heating said metallic member placed in the cavity of said forming die assembly.  
     
     
         22 . The apparatus as defined in  claim 21 , further comprising a retractable thermal insulator for insulating the metallic member to be heated from the die assembly, said insulator being retracted after heating.