表面针孔 meaning in Chinese

surface pinholes

A detailed introduction was made to the properties of the wet coated sand suitable for multi - station shell mould shooting machine ; the development of a sort of high strength coated sand with low resin content : the shaping index and wetness adjusting process : analysis and prevention of peel back defect of shells made with overturning hopper process ; test method of peel back resistance of coated sand : pinhole defect analysis of high ni ductile iron shell mould castings and application of anti - pinhole coated sand
详细介绍适用于吹砂式多工位壳型机的湿态覆膜砂性能；高强度低树脂量覆膜砂的研制；湿态壳型覆膜砂的成形性指数与调湿工艺；翻斗法制壳时的脱壳问题分析和解决办法；覆膜砂脱壳性检测方法；高镍球铁件壳型铸造表面针孔原因分析与抗针孔覆膜砂的应用。