硬さの異なる鋼材の重ね合わせフライス削りにおける超硬工具の寿命

抄録

In order to make clear the factors affecting brittle fracture of cemented carbide tool, face milling tests were carried out with cemented carbide tip (P 20) and workpieces in which hard (HV = 609) and soft (HV =141) carbon-steel plates were laminated in varied combinations. Except for cutting of the laminated plates of only soft steel, the tool failed by brittle fracture. The probability of tool failure increased (that is, number of cuts up to the occurrence of tip-corner breakage decreased) definitely by locating the hard-steel plate at the engaging side of workpiece, the tool life in this case being as short as that when cutting the hard-steel workpiece only. Further, the tool life became shorter with increasing width of soft plates in the laminated workpiece. Taking into account the result of cutting force measurements, it was suggested that cutting force generated by frank wear in contact with the hard-steel plate greatly influenced brittle fracture of cemented carbide tool.