Research on the Impact Behavior of Molten Metal on the Mold Shell in Gravity Casting of Large Titanium alloy Castings

Abstract

The impact behavior of molten metal on the mold shell in gravity casting of large titanium alloy castings by investment precision castings was studied. The physical and mechanical models of the impact of molten metal on the mold shell during the pouring process were constructed using numerical simulation. The effects of molten metal pouring rate and pouring weight on the maximum impact force of the mold shell were studied. The research results indicated that during the entire pouring process, the impact force of the first molten metal contacting the mold shell was higher than subsequent molten metal. The maximum impact force increased with the increase of pouring rate and pouring weight. The total impact force of the molten metal on the mold shell was composed of the instantaneous impact force converted from instantaneous impulse and itself gravity. The instantaneous impact force of the molten metal that first impacts the mold shell was much greater than its own gravity, while the impact force of the molten metal at the end of pouring was much less than its own gravity. The maximum impact force on the mold shell of a large casting with a pouring weight of 800kg was about three times higher than that of a medium-sized casting with a pouring weight of 80kg.The difference in the total impact force on the mold shell between them mainly comes from the instantaneous impact force converted from instantaneous impulse.