PROCESS OF ULTRASONIC TREATMENT OF MELT OF HYPEREUTECTIC SILUMINS

metallurgy of light alloys. SUBSTANCE: proposed invention is related to process of ultrasonic treatment of melt while producing castings of hypereutectic silumins of piston group. Process includes successive operations of degassing and modifying of melt by injection of modifying additions containing phosphorus. Ultrasonic treatment of flow of melt with provision for developed cavitation in melt is conducted after modifying in accordance with invention. Treatment is carried out in such manner that volume of cavitation area corresponds to total volume of melt passing through zone of ultrasonic treatment. Duration of ultrasonic treatment of each element of flow of melt is from 0.15 to 1.2 s depending on concentration of above-mentioned additions in melt. Longer treatment corresponds to lesser concentration of additions. Concentration of specified additions lies within limits from 0.01 to 0.06%. EFFECT: improved operational characteristics of shaped castings from hypereutectic silumins ( mainly, cast pistons for internal combustion engines ), raised fatigue strength of castings under high working temperatures, increased fretting resistance and some other characteristics depending on dispersity of crystals of primary silicon in structure of alloy. 2 cl, 4 tbl