A356과 ADC12 합금 용탕의 수소함량이 수축 결함에 미치는 영향

Abstract

A356 and ADC12,Aluminum alloy for casting, are excellent in fluidity, casting crack prevention, reduced solidification shrinkage and wear resistance due to high Si content. But when hydrogen concentration in the molten metal is high, pores are generated and enlarged to produce solidification shrinkage defects. Many previous studies have analyzed the effect of hydrogen on the shrinkage through experiments or simulations to suppress casting defects. Inthisstudy,wetriedtofindouttheeffectofvariousconcentrationsof hydrogen on the shrinkage defects. Whenmeltingaluminum,ifthegeneratedhydrogenexceedsthecritical solubility in the melt, the gas pressure increases during solidification. Then pores are generated when the hydrogen gas pressure is greater than the external pressure. After the pores are formed, if the pores are surrounded amongdendrites,theybecomeshrinkagedefectswhensolidificationis completed. According to Sievert's law, the solubility of hydrogen increase in liquidaluminumasthetemperatureincreases.Usingthisphenomenon, hydrogen concentration was controlled by the melt temperature in this study. Then we analyzed the shrinkage distribution induced by hydrogen.|A356 and ADC12,Aluminum alloy for casting, are excellent in fluidity, casting crack prevention, reduced solidification shrinkage and wear resistance due to high Si content. But when hydrogen concentration in the molten metal is high, pores are generated and enlarged to produce solidification shrinkage defects. Many previous studies have analyzed the effect of hydrogen on the shrinkage through experiments or simulations to suppress casting defects. Inthisstudy,wetriedtofindouttheeffectofvariousconcentrationsof hydrogen on the shrinkage defects. Whenmeltingaluminum,ifthegeneratedhydrogenexceedsthecritical solubility in the melt, the gas pressure increases during solidification. Then pores are generated when the hydrogen gas pressure is greater than the external pressure. After the pores are formed, if the pores are surrounded amongdendrites,theybecomeshrinkagedefectswhensolidificationis completed. According to Sievert's law, the solubility of hydrogen increase in liquidaluminumasthetemperatureincreases.Usingthisphenomenon, hydrogen concentration was controlled by the melt temperature in this study. Then we analyzed the shrinkage distribution induced by hydrogen.