Numerical Simulation and Experimental Study of an Ultrasonic Waveguide for Ultrasonic Casting of 35CrMo Steel

To achieve ultrasonic casting of 35CrMo steel, the waveguide unit for introducing ultrasound into liquid steel was studied numerically and experimentally. The structure and length of the ultrasonic waveguide were optimized by modal analysis. The simulation results showed that a T-shaped waveguide unit matched the vibrational system better than an L-shaped unit. The performance of T-shaped waveguide unit was optimized when the length of the ultrasound radiator was 135 mm. The performance of the T-shaped waveguide unit was investigated in ultrasonic casting experiments, and the effect of ultrasound on the microstructure of 35CrMo steel was examined. The experimental results showed that the T-shaped waveguide was able to successfully introduce ultrasound into the 35CrMo melt. In addition, the use of a silicon nitride ceramic radiator avoided high-temperature corrosion in the molten metal. The microstructure of the treated area was significantly refined and equiaxed grains were obtained. The results represented a novel method for ultrasonic casting of steel.