Method and Apparatus For Producing A Forged Compressor Wheel

Abstract

An improved forging process includes the steps of pre-heating the top and bottom dies of a forging press to a specified temperature, and maintaining both dies at the specified temperature during subsequent forging operation with closed-loop temperature control systems. The top and bottom forging dies are each coupled to a dedicated thermic fluid heater, the temperature of each die is individually measured and compared to a respective target temperature, and the respective thermic fluid heaters are controlled in relation to detected deviations of the measured temperatures from the target temperatures. Compressor wheel preforms produced according to this process consistently exhibit primarily radial grain orientations that exactly match the expected values.

1 . A method of manufacturing forged aluminum compressor wheel preforms that consistently exhibit primarily radial grain orientation characteristics that conform to a desired value, the method comprising the steps of:
 pre-heating an aluminum ingot for forging by the top and bottom dies of a forging press, and concurrently pre-heating the top and bottom dies of the forging press;   transferring the pre-heated ingot to the bottom die of the forging press;   activating the forging press to forge a compressor wheel preform from the ingot, and closed-loop controlling the temperatures of the top and bottom dies to respective target temperatures during such forging; and   deactivating the forging press upon completion of the forging and removing the compressor wheel preform from the forging press.   
     
     
         2 . The method of  claim 1 , where the step of closed-loop controlling the temperatures of the top and bottom dies comprises the steps of:
 continuously measuring the temperatures of the top and bottom dies during the activation of said forging press;   adjusting the temperature of the top die according to a difference between the measured temperature of the top die and a target temperature for the top die during the activation of said forging press; and   adjusting the temperature of the bottom die according to a difference between the measured temperature of the bottom die and a target temperature for the bottom die during the activation of said forging press.   
     
     
         3 . A forging apparatus for producing a forged aluminum compressor wheel preform that consistently exhibits primarily radial grain orientation characteristics that conform to a desired value, comprising:
 a forging press having top and bottom dies for forging said compressor wheel preform from a pre-heated aluminum ingot, each of the top and bottom dies having peripheral cavities;   a first thermic fluid heater coupled to said top die and circulating fluid through the peripheral cavity of said top die;   a second thermic fluid heater coupled to said bottom die and circulating fluid through the peripheral cavity of said bottom die; and   a controller responsive to measured temperatures of said top and bottom dies and coupled to said first and second thermic fluid heaters to preheat said top and bottom dies prior to the forging of said compressor wheel preform, and then closed-loop control the temperatures of the top and bottom dies to respective target temperatures during the forging of said compressor wheel preform.   
     
     
         4 . The forging apparatus of  claim 3 , further comprising:
 a chiller controlled by said controller to reduce the temperature of fluid supplied to said top or bottom dies when the measured temperatures of said top and bottom dies fall below the respective target temperatures.   a forging press having top and bottom dies for forging said compressor wheel preform from a pre-heated aluminum ingot, each of the top and bottom dies having peripheral cavities;   a first thermic fluid heater coupled to said top die and circulating fluid through the peripheral cavity of said top die;   a second thermic fluid heater coupled to said bottom die and circulating fluid through the peripheral cavity of said bottom die; and   a controller responsive to measured temperatures of said top and bottom dies and coupled to said first and second thermic fluid heaters to preheat said top and bottom dies prior to the forging of said compressor wheel preform, and then closed-loop control the temperatures of the top and bottom dies to respective target temperatures during the forging of said compressor wheel preform.   
     
     
         4 . The forging apparatus of  claim 3 , further comprising:
 a chiller controlled by said controller to reduce the temperature of fluid supplied to said top or bottom dies when the measured temperatures of said top and bottom dies fall below the respective target temperatures.