The pores distributed in groups are formed by the chemical reaction between some components in the molten metal or between the molten metal and the core on the surface. The needle shaped or waist round reaction pores on the surface of castings are called surface needle holes and subcutaneous pores, which are caused by the interface reaction between molten metal and mold and core coating. The needle reaction pores scattered or distributed in groups on the whole section of the casting or in a local area.

Because the furnace charge is wet, rusty, greasy and humid, the smelting tools and ladle are not dried, the composition of the molten metal is improper, and the refining of the alloy liquid is insufficient, the molten metal contains a large amount of gas or gaseous substances, resulting in the precipitation of air holes or reaction air holes in the casting. Dalian motor housing

The core is not fully dried, with poor air permeability, poor ventilation, too much moisture and gas generating substances, the coating is not dried or contains too much gas generating components, the chill and core support have rust spots, oil stains or are not dried, and the metal mold exhaust is poor, forming intrusive pores in the casting.

The pouring system is unreasonable, the pouring and mold filling speed is too fast, and the exhaust of the metal mold is poor, which causes the metal liquid to generate turbulence, eddy current or cut-off during the pouring and mold filling process, resulting in gas entrainment, forming entrainment pores in the casting, and the alloy liquid is easy to inhale. Effective refining, protection and purification measures are not taken during the smelting and pouring process, resulting in a large amount of gas, slag and gas entrainment in the metal liquid, Precipitation pores and reaction pores are formed during mold filling and solidification.

The pores distributed in groups are formed by the chemical reaction between some components in the molten metal or between the molten metal and the core on the surface. The needle shaped or waist round reaction pores on the surface of castings are called surface needle holes and subcutaneous pores, which are caused by the interface reaction between molten metal and mold and core coating. The needle reaction pores scattered or distributed in groups on the whole section of the casting or in a local area.

Because the furnace charge is wet, rusty, greasy and humid, the smelting tools and ladle are not dried, the composition of the molten metal is improper, and the refining of the alloy liquid is insufficient, the molten metal contains a large amount of gas or gaseous substances, resulting in the precipitation of air holes or reaction air holes in the casting. Dalian motor housing

The core is not fully dried, with poor air permeability, poor ventilation, too much moisture and gas generating substances, the coating is not dried or contains too much gas generating components, the chill and core support have rust spots, oil stains or are not dried, and the metal mold exhaust is poor, forming intrusive pores in the casting.

The pouring system is unreasonable, the pouring and mold filling speed is too fast, and the exhaust of the metal mold is poor, which causes the metal liquid to generate turbulence, eddy current or cut-off during the pouring and mold filling process, resulting in gas entrainment, forming entrainment pores in the casting, and the alloy liquid is easy to inhale. Effective refining, protection and purification measures are not taken during the smelting and pouring process, resulting in a large amount of gas, slag and gas entrainment in the metal liquid, Precipitation pores and reaction pores are formed during mold filling and solidification.