Studies on Chip Control in Turning by Partially Laser Hardening of Carbon Steel

抄録

This study deals with the chip control in turning by in-situ laser heat treatment of work material. Medium carbon steel JIS S45C is chosen as workpiece material because the ductile ferrite-pearlite structure of the base material can be relatively easily changed into the hard-brittle martensitic structure by laser heat. For the purpose of practical use, the direct diode laser (DDL) is selected because of its compact size, easiness of handling and high absorbance. Prior to turning process, the continuous-wave laser beam is irradiated on the workpiece surface in a longitudinal direction. This linear heat treatment makes it possible to break chips in turning every one revolution of workpiece at which the material is embrittled. The chip breakability depends mainly on the ratio of heat-treated depth to depth of cut. In spite that the workpiece is partially hardened, abnormal wear or chipping is not observed on the tool face after turning.