Forming apparatus and forming method

Abstract

A forming apparatus that forms a metal pipe material includes an electrode that holds the metal pipe material and supplies electric power to the metal pipe material to heat the metal pipe material, a forming die that quenches and forms the expanded metal pipe, and a member that suppresses quenching, in which a region where quenching is not performed in the metal pipe is adjusted by adjusting a length of the member.

What is claimed is: 
     
         1 . A forming apparatus that forms a metal pipe material, the apparatus comprising:
 an electrode that holds the metal pipe material, and supplies electric power to the metal pipe material to heat the metal pipe material;   a forming die that quenches and forms the expanded metal pipe; and   a member that suppresses quenching, wherein   a region where quenching is not performed in the metal pipe is adjusted by adjusting a length of the member.   
     
     
         2 . The forming apparatus according to the  claim 1 , wherein
 the member is an insulating material and a sliding material arranged in order from an electrode side, and   a sum of a thickness of the insulating material and a thickness of the sliding material in an array direction of the insulating material and the sliding material is greater than a contact length between the electrode and the metal pipe material in a longitudinal direction of the metal pipe material.   
     
     
         3 . The forming apparatus according to the  claim 2 , wherein
 the forming die includes an upper die and a lower die,   the electrode includes an upper electrode and a lower electrode,   an upper insulating material and an upper sliding material are arranged between the upper electrode and the upper die, in order from an upper electrode side, and   a lower insulating material and a lower sliding material are arranged between the lower electrode and the lower die, in order from a lower electrode side.   
     
     
         4 . The forming apparatus according to the  claim 3 , wherein
 the upper insulating material and the upper sliding material are fixed to each other by a fixer, and   the lower insulating material and the lower sliding material are fixed to each other by a fixer.   
     
     
         5 . The forming apparatus according to the  claim 4 , wherein
 each of the fixer between the upper insulating material and the upper sliding material and the fixer between the lower insulating material and the lower sliding material includes a bolt and a female screw.   
     
     
         6 . The forming apparatus according to the  claim 3 , wherein
 the upper sliding material is sprayed onto the upper insulating material, and   the lower sliding material is sprayed onto the lower insulating material.   
     
     
         7 . The forming apparatus according to the  claim 3 , wherein
 the upper sliding material is fixed to the upper die, and   the lower sliding material is fixed to the lower die.   
     
     
         8 . The forming apparatus according to the  claim 3 , wherein
 a first concave groove having a semi-arc-shape corresponding to a shape of an outer peripheral surface of the metal pipe material is formed on each of surfaces of the upper electrode and the lower electrode facing each other.   
     
     
         9 . The forming apparatus according to the  claim 8 , wherein
 a second concave groove having a semi-arc-shape is formed on each of surfaces of the upper insulating material and the lower insulating material facing each other and surfaces of the upper sliding material and the lower sliding material facing each other, and   the second concave groove has a diameter greater than a diameter of the first concave groove.   
     
     
         10 . The forming apparatus according to the  claim 9 , wherein
 a tapered concave surface which is recessed with a periphery thereof inclined to form a tapered shape toward the first concave groove is formed on a surface of the electrode facing an outside of the forming die.   
     
     
         11 . The forming apparatus according to the  claim 1 , wherein
 a refrigerant flow path for circulating a cooling medium is formed inside the electrode.   
     
     
         12 . A forming method for expanding a metal pipe material and forming a metal pipe, the method comprising:
 heating the metal pipe material; and   forming the metal pipe material expanded by using a forming die, wherein   in the heating of the metal pipe material, a region where quenching is not performed in the metal pipe is adjusted by a member that suppresses quenching, and of which a length is adjusted.