Microstructure, residual stress, and nanoindentation properties of GCr15-bearing steel by cryogenic treatment and laser-peening composite strengthening

GCr15-bearing steel is widely used in generator bearings. To improve its mechanical properties, the cryogenic treatment and laser-peening (CT + LP) composite strengthening process and properties of GCr15-bearing steel were studied in this paper. The microstructure, residual stress distribution and nanoindentation properties of GCr15-bearing steel under CT + LP composite strengthening were studied by X-ray diffraction, scanning electron microscope, transmission electron microscope, X-ray stress analyzer and nanoindentation instrument. The experimental results showed that the residual compressive stress value and FWHM (full width at half maximum) value of the surface of GCr15-bearing steel increased after CT + LP composite strengthening, and the microstructure characteristics such as dislocation entanglement, proliferation, subgrain boundary and nanocrystalline appeared inside the CT + LP specimen. The nano-hardness and elastic modulus of CT + LP sample were 6.55 and 221.95 GPa, respectively, which were 12.94% and 32.61% higher than that of the untreated sample, respectively. The nanoindentation properties and deformation resistance of GCr15-bearing steel were improved.

Automated summary

This paper studied the cryogenic treatment and laser-peening (CT + LP) composite strengthening process and properties of GCr15-bearing steel. The microstructure, residual stress distribution, and nanoindentation properties of GCr15-bearing steel under CT + LP composite strengthening were investigated. The experimental results showed that CT + LP composite strengthening increased the residual compressive stress value and FWHM value of the surface, improved the nano-hardness and elastic modulus, and enhanced the nanoindentation properties and deformation resistance of GCr15-bearing steel.