Bicycle seat rail manufacturing method

Abstract

A bicycle seat rail manufacturing method includes the steps of: pre-annealing, providing an aluminum alloy workpiece having undergone pre-annealing; first-stage heat treatment, performing heat treatment of full annealing on the aluminum alloy workpiece by a bending shaping, calendaring the aluminum alloy workpiece by a calendering shaping for a cooling time period, and bombarding the aluminum alloy workpiece by a cold forging shaping to increase its cross-sectional area; second-stage heat treatment, enhancing hardness of the aluminum alloy workpiece by a quenching shaping, and enhancing internal structure stability of the aluminum alloy workpiece by a tempering shaping; and cryogenic treatment, performing high-speed bombardments on the surface of the aluminum alloy workpiece by a shot blasting shaping to enhance its durability and service life. Therefore, a bicycle seat rail integrally formed of aluminum alloy is manufactured by the aforesaid steps.

What is claimed is: 
     
         1 . A bicycle seat rail manufacturing method, comprising the steps of:
 pre-annealing, providing an aluminum alloy workpiece and performing heat treatment of pre-annealing;   first-stage heat treatment, having a bending shaping, a calendering shaping and a cold forging shaping, applying a full annealing temperature to the aluminum alloy workpiece by the bending shaping, heating the aluminum alloy workpiece again by the calendering shaping for a cooling time period, and bombarding the aluminum alloy workpiece by the cold forging shaping so as for the aluminum alloy workpiece to take on a larger cross section;   second-stage heat treatment, having a quenching shaping and a tempering shaping, enhancing hardness of the aluminum alloy workpiece by the quenching shaping, and enhancing internal structure stability of the aluminum alloy workpiece by the tempering shaping; and   cryogenic treatment, having a shot blasting shaping, performing high-speed bombardments on a surface of the aluminum alloy workpiece by the shot blasting shaping to enhance durability and service life of the aluminum alloy workpiece.   
     
     
         2 . The bicycle seat rail manufacturing method of  claim 1 , wherein the full annealing temperature is 350° C.˜400° C., and the cooling time period is 5-15 minutes. 
     
     
         3 . The bicycle seat rail manufacturing method of  claim 2 , wherein the full annealing temperature is preferably 380° C.˜390° C., and the cooling time period is preferably 10 minutes. 
     
     
         4 . The bicycle seat rail manufacturing method of  claim 1 , wherein an integrally formed seat rail is manufactured by the pre-annealing, the first-stage heat treatment, the second-stage heat treatment and the cryogenic treatment, and the seat rail has a bent segment, a support segment connected to the bent segment, an extension segment connected to the support segment, and a rear segment connected to the extension segment. 
     
     
         5 . The bicycle seat rail manufacturing method of  claim 4 , wherein the bent segment, the extension segment and the rear segment each have a round cross section in a radial direction, and the support segment has a non-round cross section in a radial direction. 
     
     
         6 . A bicycle seat rail manufacturing method, comprising the steps of:
 pre-annealing, providing an aluminum alloy workpiece and performing heat treatment of pre-annealing;   first-stage heat treatment, having a bending shaping, a calendering shaping and a cold forging shaping, applying high-frequency electromagnetic wave with high frequencies of 400-500 Hz to the aluminum alloy workpiece by the bending shaping, heating the aluminum alloy workpiece again by the calendering shaping for a cooling time period, and bombarding the aluminum alloy workpiece by the cold forging shaping so as for the aluminum alloy workpiece to take on a larger cross section;   second-stage heat treatment, having a quenching shaping and a tempering shaping, enhancing hardness of the aluminum alloy workpiece by the quenching shaping, and enhancing internal structure stability of the aluminum alloy workpiece by the tempering shaping; and   cryogenic treatment, having a shot blasting shaping, performing high-speed bombardments on a surface of the aluminum alloy workpiece by the shot blasting shaping to enhance durability and service life of the aluminum alloy workpiece.   
     
     
         7 . The bicycle seat rail manufacturing method of  claim 6 , wherein an integrally formed seat rail is manufactured by the pre-annealing, the first-stage heat treatment, the second-stage heat treatment and the cryogenic treatment, and the seat rail has a bent segment, a support segment connected to the bent segment, an extension segment connected to the support segment, and a rear segment connected to the extension segment. 
     
     
         8 . The bicycle seat rail manufacturing method of  claim 7 , wherein the bent segment, the extension segment and the rear segment each have a round cross section in a radial direction, and the support segment has a non-round cross section in a radial direction.