Effect of Ultrasonic Impact Treatment on the Structure and Properties of the Surface Layer of a 40Cr13 Steel Billet

A 40Cr13 steel billet has been used as an example to assess the effect of indenter load during ultrasonic impact treatment on the microstructure and geometric parameters of the treatment zone and the hardness of the material. The results demonstrate that the optimal indenter load for the 40Cr13 steel billet material is 200 N. The ultrasonic impact treatment conditions chosen lead to considerable changes in the structure (a decrease in the particle size of the carbides and an increase in their volume fraction) and properties (an increase in hardness) of the surface layer of the samples studied.