一、前言在铝硅合金的砂型铸造中,在炉前断口和拉力试棒的断口上,经常出现白点,严重时影响到合金的性能。关于白点的实质,有一种看法认为是熔化温度过高,除气温度过高,熔化过程吸气太多所造成;另一种看法认为这种现象与加钠变质有关。为了正确的判断缺陷,我 I. Preface In the sand casting of Al-Si alloy, white spots often appear on the fracture of the fracture and tensile test bars in front of the furnace, which seriously affect the performance of the alloy. On the essence of the white point, there is a view that the melting temperature is too high, the gas temperature is too high, the melting process is too much caused by inspiratory; another view that this phenomenon is associated with sodium deterioration. In order to correctly judge the defects, I