Strain weakening of metallic materials

Abstract

A method for controlling the work hardening of a metal component during cold forming by using an electric current passing through the component is provided. The method can include providing a cold forming machine with at least a pair of dies, the machine operable to perform a cold forming operation and apply an electric direct current to a metal component placed in contact with the dies. In addition, the method includes providing a metal component and placing the metal component between the at least a pair of dies. Thereafter, cold forming of the metal component is performed with an electric direct current applied to the component during at least part of the time the component is being cold formed. In some instances, the cold forming is compressive cold forming. The direct current can be applied before or after the cold forming has started and/or be terminated before or after the cold forming has stopped.

1 . A method for controlling the work hardening of a metal component during cold forming using an electrical direct current passing through the component, the method comprising:
 providing a cold forming machine, the cold forming machine having at least a pair of dies and operable to perform a cold forming operation to a metal component placed in contact with the dies;   providing an electric current source operable to pass electrical direct current through a metal component;   providing a metal component;   placing the metal component between the at least a pair of dies;   cold forming the metal component when it is between the at least a pair of dies; and   applying the electrical direct current to the metal component during at least part of the time the metal component is being cold formed, for the purpose of controlling the work hardening of the metal component during the cold forming.   
     
     
         2 . The method of  claim 1 , wherein the cold forming is a compressive cold forming. 
     
     
         3 . The method of  claim 1 , wherein the current is applied after the cold forming has started. 
     
     
         4 . The method of  claim 1 , wherein the current is terminated before the cold forming has been terminated. 
     
     
         5 . The method of  claim 1 , wherein the current is cycled during the cold forming. 
     
     
         6 . The method of  claim 1 , wherein a current density of the current is increased during the cold forming. 
     
     
         7 . The method of  claim 1 , wherein a current density of the current is decreased during the cold forming. 
     
     
         8 . The method of  claim 1 , wherein the metal is selected from a group consisting of iron, aluminum, titanium, copper and alloys thereof. 
     
     
         9 . The method of  claim 1 , further comprising the cold forming machine having at least a pair of electrodes for applying the current to the metal component, the at least a pair of electrodes being insulated from the cold forming machine. 
     
     
         10 . A method for controlling the work hardening of a metal component during compressive cold forming using an electrical direct current passing through the component, the method comprising:
 providing a compressive cold forming machine, the cold forming machine having at least a pair of dies operable to perform a cold forming operation and at least a pair of electrodes operable to apply an electrical direct current to a metal component placed between the dies, the at least a pair of electrodes being insulated from the cold forming machine;   providing a metal component;   placing the metal component between the at least a pair of dies;   compressive cold forming the metal component when it is between the at least a pair of dies; and   applying the electrical direct current to the metal component during at least part of the time it is being cold formed, for the purpose of controlling the work hardening of the metal component during the cold forming.   
     
     
         11 . The method of  claim 10 , wherein the compressive cold forming machine is selected from the group consisting of a forging machine, a stamping machine, a punching machine, a rolling machine, an extrusion machine and a bending machine. 
     
     
         12 . The method of  claim 10 , wherein the current is applied after the cold forming has started. 
     
     
         13 . The method of  claim 10 , wherein the current is terminated before the cold forming has stopped. 
     
     
         14 . The method of  claim 10 , wherein the current is cycled during the cold forming. 
     
     
         15 . The method of  claim 10 , wherein a current density of the current is increased during the cold forming. 
     
     
         16 . The method of  claim 10 , wherein a current density of the current is decreased during the cold forming.