Experimental study on the process of adiabatic shear fracture in isolated segment formation in high-speed machining of hardened steel

Adiabatic shear fracture in serrated chip leads to isolated segment formation in high-speed machining with the further increase of cutting speed. An energy model of adiabatic shear band is built and investigated through high-speed machining tests and chip morphology examination. A quick-stop device designed to obtain chip roots in high-speed turning is applied. The adiabatic shear fracture process on considering the induced mechanism is investigated and the multi-stage physical model of adiabatic shear fracture is proposed through chip root morphology examination. The results show that adiabatic shear fracture in high-speed machining is a periodic process from energy convergence to release. The shear band collapses and results in isolated segments formation when the energy convergence in band exceeds the saturation limit. There are possibilities of utilizing the occurrence of adiabatic shear fracture to reduce the increased rate of stress, temperature, and energy and optimize the machinability in the chip formation aspect in high-speed machining.

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