THE EFFECT OF OVERHEATING TEMPERATURE AND MELT POURING TEMPERATURE ON THE ALUMINUM ALLOY CASTING QUALITY IN LOST FOAM CASTING

Abstract

Lost foam casting (LFC) is currently one of the most effective and promising methods to produce high-quality thin-walled castings that exhibit a desired dimensional accuracy, the required surface roughness, and other properties. This technology is widely used in the manufacture of aluminum alloys products. In order to ensure cost minimization in the manufacture of products and the production of quality castings, it is advisable to use an increased amount of recycled material in the charge, paying attention to the overheating temperature and the melt holding time. The paper presents research findings on temperature regimes of melting and casting of aluminum alloys during LFC. Under the concerned industrial conditions, the following regimes were most effective to ensure the best quality indicators of leak-tight castings with respect to dimensional accuracy and surface roughness: melt overheating temperature – 880÷890 °С, pouring temperature – 820÷830 °С. The paper studies the effect of different temperature parameter options for melting and casting of the AK7 melt composition during LFC on the content of nonmetallic inclusions in the as-cast state. It was found that the minimum content of γ-Al 2 O 3 in the finished alloy was provided by the melt overheating temperature up to 880÷890 or 940÷950 °С, and the pouring temperature of 820÷830 °С.