1
Zhigang Fang: Pressure molded powder metal milled tooth rock bit cone. Smith International, Christie Parker & Hale, October 5, 1999: US05963775 (71 worldwide citation)

A milled tooth shaped rotary cone drill bit for drilling oil wells and the like manufactured using a powder metallurgy process in which an alloy powder is pressure molded into the desired bit shape, sintered, and precision machined.


2
Fang Zhigang: Pressure molded powder metal milled tooth rock bit cone.. Smith International, June 11, 1997: GB2307918-A

A milled tooth shaped rotary cone drill bit for drilling oil wells and the like manufactured using a powder metallurgy process in which an alloy powder is pressure molded into the desired bit shape, sintered, and precision machined.


3
Fang Zhigang: Trepan a cone a denture fraisee en metal en poudre moulee sous pression, Pressure molded powder metal milled tooth rock bit cone. Smith International, OYEN WIGGS GREEN & MUTALA, January 30, 2001: CA2191662

A milled tooth shaped rotary cone drill bit for drilling oil wells and the like manufactured using a powder metallurgy process in which an alloy powder is pressure molded into the desired bit shape, sintered, and precision machined.



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