Compared with grinding, hard turning has the potential to make a variety of
precision components of superior surface integrity, such as bearings, gears, cams, shafts,
tools, dies, etc., while reducing investment, increasing production rate, and eliminating
environmental pollution. Despite its spectrum of advantages over cost intensive grinding
process, industrial realization of hard turning still remains in incipient stage. The low
industrial acceptance of hard turning may be attributed to uncertainty related to surface
quality especially for the white layer which is a key factor of surface integrity and thus
product performance.
A comparative study has been conducted to solve the current problems. Hard
turning and grinding AISI 52100 (62 to 64 HRC) steel were designed and conducted to
generate the white layer. Then, white layer induced by hard tuning and grinding were
characterized and compared in six aspects: (1) Surface structure by optical microscope;
(2) Hardness by microhardness tester; (3) Microstructure by scanning electron
microscopy (SEM); (4) Chemical composition by X-ray photo spectroscopy (XPS); (5)
Retained austenite phase by X-ray diffraction; (6) Crystal defects and microstructure by
Transmission Electron Microscopy (TEM).
