Increasing in efficiency of surface hardening of structural steels by HFC hardening and ultrasonic treatment

The surface plastic deformation of structural steels was studied using ultrasound. Four variants of hardening are considered: ultrasonic treatment with continuous supply of ultrasonic energy, pulsed ultrasonic treatment, a combination of ultrasonic treatment followed by pulsed treatment, and ultrasonic treatment after quenching with induction heating. It is shown that UST increases the microhardness of the surface layer of structural steels by 1.5 times, HFC hardening by more than 2 times, combinations of HFC hardening + UST by 3 times, and HFC + UST hardening by 3.2 times. Ultrasonic treatment increases the compressive stresses that occur in the steel surface hardened by HFC hardening. Compressive stresses increase especially strongly after pulsed ultrasonic treatment with five passes and reach a value of 1200 MPa.