INSERT CHIP FOR PETROLEUM EXCAVATION TRICONE BIT, MANUFACTURING METHOD THEREOF, AND PETROLEUM EXCAVATION TRICONE BIT

摘要

PROBLEM TO BE SOLVED: To attain both wear resistance and crack resistance in an insert chip used for a petroleum excavation tricone bit or the like. SOLUTION: This insert chip for petroleum excavation tricone bit comprises an insert chip base material 10 comprising a cylindrical part and a cutting edge part for performing an excavation and formed of a cemented carbide having a first composition and a coating cemented carbide layer 20 formed by laminating two or more coating layers 11, 12 and 13 formed of cemented carbides having compositions different from the first composition so as to cover the whole cutting edge part of the insert chip base material 10. The thickness of each of the coating layers at a cutting edge tip part 3 is >=0.1 mm and <=2.5 mm, the total thickness of the coating cemented carbide layer 20 is >=1 mm and <=5 mm, and the outermost cemented carbide layer on the outermost surface of the coating layers has a hardness higher than those of the other coating layers and the insert chip base material 10.