Method for manufacturing cold-forged extruded aluminum alloy rod

Abstract

A method for manufacturing a cold-forged extruded aluminum alloy rod includes the steps of: (A) preparing a primary material and a cold extrusion apparatus including a cold extrusion die and a cold extrusion punch corresponding in position to the cold extrusion die; (B) processing the primary material to form a solid preform; (C) subjecting the preform to a homogeneous annealing; (D) testing the hardness of the preform; (E) immersing the preform in a tank containing a lubricant for a predetermined time, (F) applying talcum powder on the preform; and (C) subjecting the preform to cold forging to thereby forming the cold-forged extruded aluminum alloy rod.

What is claimed is: 
     
         1 . A method for manufacturing a cold-forged extruded aluminum alloy rod, comprising the steps of:
 (A) preparing a primary material having a block shape and made of an aluminum alloy material, and at least one cold extrusion apparatus including a cold extrusion die, and a cold extrusion punch corresponding in position to the cold extrusion die;   (B) processing the primary material to form a solid preform that extends along an axis and that has a first end surface intersecting the axis, a second end surface opposite to the first end surface along the axis, and an outer circumferential surface inter-connecting outer circumferential edges of the first end surface and the second end surface, the preform having a length extending from the first end surface to the second end surface, and an outer diameter measured across the outer circumferential surface;   (C) subjecting the preform to a homogeneous annealing which involves heating the preform in a furnace to a temperature ranging from about 410° C. to 510° C., and then removing the preform from the furnace after the furnace is cooled to a temperature ranging from about 160° C. to 200° C. at a cooling rate of 10° C. per hour;   (D) testing the hardness of the preform, the hardness being equal to or below 60 degrees measured on Rockwell Hardness F scale;   (E) immersing the preform in a tank containing a lubricant for a predetermined time;   (F) applying talcum powder on the first end surface, the second end surface and the outer circumferential surface of the preform after the preform is immersed in the lubricant; and   (G) subjecting the preform to cold forging which involves positioning the preform in the cold extrusion die, after which the cold extrusion punch is operated to strike against the preform to thereby form the cold-forged extruded aluminum alloy rod, the cold-forged extruded aluminum alloy rod being a solid rod that extends along the axis, and having a first side surface intersecting the axis, a second side surface opposite to the first side surface along the axis, and an outer circumferential surface interconnecting outer circumferential edges of the first side surface and the second side surface, the cold-forged extruded aluminum alloy rod having a length that extends from the first side surface to the second side surface thereof and that is longer than the length of the preform.   
     
     
         2 . The method of  claim 1 , wherein in step (D), the testing of the hardness of the preform is performed at multiple points of the outer circumferential surface of the preform and at equal intervals along the axis. 
     
     
         3 . The method of  claim 2 , further comprising a step (H) after step (G), wherein step (H) involves repeating step (C) to step (G) at least once, and wherein the number of the cold extrusion apparatus prepared in step (A) corresponds to the number of times that step (C) to step (G) is repeated. 
     
     
         4 . The method of  claim 3 , wherein an advanced forming apparatus is further prepared in step (A), the advanced forming apparatus including a forming die that has a molding die cavity, and a forming punch corresponding in position to the forming die, the method further comprising a step (I) after step (H), wherein step (T) involves positioning the cold-forged extruded aluminum alloy rod in the molding die cavity, after which the forming punch is operated to strike against the cold-forged extruded aluminum alloy rod to thereby form a patterned cold-forged extruded aluminum alloy rod. 
     
     
         5 . The method as claimed in  claim 1 , wherein the aluminum alloy material for making the primary material in step (A) is AL6066 aluminum alloy. 
     
     
         6 . The method as claimed in  claim 1 , wherein the aluminum alloy material for making the primary material in step (A) is AL7050 aluminum alloy. 
     
     
         7 . The method as claimed in  claim 1 , wherein the predetermined time in step (E) is 4 to 5 minutes. 
     
     
         8 . The method as claimed in  claim 1 , wherein the lubricant used in step (E) has a free total acidity (TA) concentration ranging from 40% by weight to 50% by weight at a working temperature ranging from 80° C. to 100° C. 
     
     
         9 . The method as claimed in  claim 3 , wherein the lubricant; used in step (E) is boron nitride. 
     
     
         10 . The method as claimed in  claim 1 , wherein the lubricant used in step (E) is a liquid grease. 
     
     
         11 . The method as claimed in  claim 10 , wherein the lubricant used in step (E) has a viscosity index of equal to or above 170, a flash point of equal to or above 240° C., a pour point of equal to or above −24° C. and a fire point of equal to or above 255° C.