Troubleshooting Surface Blowholes

铸件表面气孔缺陷排查

type:troubleshooting · level:intermediate · material:copper · material:brass · variant:green-sand · variant:plaster-investment · scale:decorative-object · equipment:furnace · stage:melting · stage:pouring

标签：气孔, 潮湿, 除气, 浇注, 缺陷

表面气孔多因型壳潮湿、金属液含气或浇注卷气。排查：①型壳焙烧是否充分干燥；②熔炼是否脱氧除气；③浇包是否预热无水；④浇注是否平稳避免卷气。黄铜尤其易因锌蒸发吸气，宜快速熔炼并覆盖。

Surface blowholes usually come from moist moulds, gassy metal or turbulent pouring. Check: ①was the shell fully dried/burned out; ②was deoxidation/de-gassing done; ③was the ladle preheated dry; ④was pouring steady without air entrainment. Brass is prone to zinc-evaporation gas pick-up — melt fast and keep it covered. ---