针孔是铸造铝合金中一种常见的缺陷,往往造成铸件的成批报废。我厂生产的1E 50F汽油机和红旗—3型高射喷粉弥雾机,铸件大部分采用铸铝合金,因针孔造成漏水报废也相当严重,就是合格铸件,针孔仍常存在。特别是汽缸,要求较高,要经过打硬度,试水压和镀硬铬,如果铸件有针孔,会使硬度偏低,漏水率高及影响镀铬层表面粗糙、粘结力降低。这样,铸件的质量就无法保证。为了消除铸件的针孔,我们曾果用氯化锰(或氯化锌)除气,每次用量为0.2%,但除气效果不能令人满意。我们又采用了氮气除气的方法,初步取得成效,现将一些肤浅的体会 Pinholes are a common defect found in cast aluminum and often result in mass scrap of the castings. I plant the production of 1E 50F gasoline engine and the red flag-3 high-jet spray fog machine, casting the majority of cast aluminum alloy, pinhole caused by leakage is also quite serious scrap, that is, qualified castings, pinholes are still there. Especially the cylinder, demanding, to go through the hardness, pressure test and hard chrome plating, if the casting pinholes, will make the hardness is low, high leakage rate and affect the chrome layer surface roughness, reduce adhesion. In this way, the quality of castings can not be guaranteed. In order to eliminate the pinhole of castings, we have used the manganese chloride (or zinc chloride) degassing, the amount of each 0.2%, but the degassing effect is not satisfactory. We have adopted a method of nitrogen degassing, the initial success, now some superficial experience