Classification of casting defects on piston surface

Casting defectCauseImprovement measures
White skirtThe temperature of molten aluminum is low, and the heat conduction differential ripening temperature of the outer mold is higher than that of the core moldIncrease the temperature of molten aluminum, improve the heat conduction of outer mold and increase the temperature of core mold
Pitting convex concave at skirt pouringPouring riser paint splashes on the mold wall;Sandpaper grinding;
Convex and concave at skirt copper plugThe copper plug is convex into the cavity or concave into the die;Flatten;
Oil storage surface hemp spotLoose texture of outer model cavity wall and graphite peeling resultsIn case of serious, the external mold is invalid,
Concave white of pin hole (junction zone between oil storage surface and ring groove surface)The heat conduction of the external mold is poor, and the mold temperature is higher than the core temperature;Improve the heat conduction of the outer mold and increase the temperature of the core mold;
Top edge drapePad up the external formwork; The base is uneven;Correct the base; Remove the slag inclusion in the mold base,
Top air pocketThe base is cool and the torrent that starts pouring is large;The temperature of the base rises, and the flow is small and slow at the beginning of pouring;
White topThe base is not drained or the water temperature is high; Poor heat conduction of the base,Enlarge the water inflow and reduce the water temperature
The top center hole seat is low and uneven,Damage and deformation of copper plug or entry of graphite and aluminum slag;Blow out the cavity;
Slag inclusion at skirt and topIf the mold closing force is too large, the core mold will be shaken off and the riser coating will be poured,Blow out the cavity and close the mold gently;
Air pocket on inner wall of stopThe core mold is only covered with water, and air waves are formed during pouring,Core mould is coated with graphite for thermal insulation
Inner wall moireCore mold crackingScrapping in serious cases,
The upper part of the outer circle of the pin hole seat is whiteHigh core mold temperatureCooling of weighted core mold
Concave convex at the copper plug on the upper part of the outer circle of the pin hole seatThe copper plug of the core mold is convex or concave,Strike even,
Pin hole blockedThe pin hole core is not inserted into the core mold or inserted too hard on one side, shaking out the core on the other side;Gently insert both sides at the same time until the core mold;
Pin hole arcDeformation of pin hole mandrel;Pin hole mandrel scrapped,
Air hole on inner wall of pin holeThe water cooling of pin hole mandrel is too cold; Or assembly with water vaporThermal insulation of pin hole core mold stained with stone ink
The upper part of the inner wall of the pin hole is whiteHigh pin temperature;Re cooling pin
Crack at lower part R of pin hole seatThe core mold rises too early; The core mold is deformed and warped,Postpone core pulling and pay attention to core pulling mode; The drape joint is too large, the core mold is scrapped, and the aluminum sticking is removed,