Enhanced wear resistance by combined ultrasonic impact and electro-spark melting

Abstract

A novel surface modification method coupling surface melting and ultrasonic impact treatment (UIT) was developed to improve the wear resistance of S355 steel. The principle of ultrasonic impact electro-spark melting treatment (UIEMT) was presented, and the microstructure and surface plastic deformation layer were characterised by scanning electron microscopy, optical microscopy and X-ray diffraction (XRD). The obtained results revealed that UIEMT has more advantage than the UIT method. For UIEMT sample, fine microstructure with the average grain size of less than 2 μm was obtained, and the hardening layer was about 2.75 times deeper than the UIT one. The microhardness profile and residual compressive stress distribution showed a good correlation with the microstructural transition. In addition, no martensite transformation can be found by XRD. It was concluded that UIEMT can significantly improve the wear resistance without changing the chemical composition of the material.

Perspectives of Using Ultrasonic surface hardening in Machine Part Manufacturing

“…The papers devoted to investigating the effect of ultrasonic surface hardening on the wear resistance of parts processed by the combined methods are also known. The wear resistance of the samples processed by ultrasonic impact electro-spark melting treatment can be significantly improved without changing the chemical composition of the material [4]. Paper [5] presents the results of experimental investigations on improving the tribological pair "wheel -rail" by ultrasonic surface hardening, which prove its efficiency in comparison with heat-treatment.…”