铸造铝合金的主要缺陷之一是针孔。熔炼铝合金时,炉料、工具以及气候的好坏是造成合金含气的潜在条件。铝合金中所含的气体90％以上为氢气。离子状态的氢在铝合金液中有较大的溶解度,但随着温度降低,溶解度相应减少,在凝固过程中大量析出而形成针孔,严重影响铸件质量。因此,熔炼铝合金时必须进行除气处理。 One of the major drawbacks of casting aluminum alloys is pinholes. The melting of aluminum alloy, charge, tool and the climate is good or bad conditions caused by alloy gas. More than 90% of the gas contained in the aluminum alloy is hydrogen. The ionic state of hydrogen in the aluminum alloy liquid has greater solubility, but as the temperature decreases, the corresponding decrease in solubility in the solidification process precipitation and the formation of a large number of pinholes, seriously affecting the quality of castings. Therefore, the aluminum alloy must be degassing process.