Reducing Porosity in 35crmo Steel Sand-Cast by Ultrasonic Processing

The influence of ultrasonic processing on porosity defects of 35CrMo steel sand-cast ingot was studied. A self-developed ultrasonic-introduced method was applied to carry out the ultrasonic experiment. The acoustic pressure and melt velocity field were calculated through numerical simulation, which plays an auxiliary role in the analysis of the influence of ultrasound on the molten steel. Comparing the porosity of ultrasonic castings and direct castings, the results reveal that ultrasonic processing could reduce the porosity defects of ingot significantly, thus the mechanical properties of castings could be significantly improved. The ultrasound tends to attenuate when propagating in the steel melt. The porosity at the central area of ingot reduced more apparent than that at the edge area. In addition, the mechanism of the effect of ultrasound on porosity reduction was also discussed. (paper)