Pockmark is one of the common surface defects of investment aluminum castings, also known as pockmark, pockmark, oxidation pockmark, etc. Generally speaking, this kind of defect can not be repaired and can only be scrapped. It not only increases the production cost, but also affects the normal delivery time. Therefore, how to avoid and eliminate the pitting defects of aluminum castings is one of the main tasks of casting work. What are the precautions? The following aluminum casting manufacturer answers for you.
1. Reduce and reduce the oxide in liquid metal, improve the quality of liquid metal.
Select dry and clean charge, control the times or quantity of reuse, and avoid adding oxide in charge. The method of complete deoxidization is adopted, first adding ferromanganese, then ferrosilicon, then adding silicon calcium reduction, then cutting off the electric energy, then adding aluminum for final deoxidization, and then taking it out of the furnace and aluminum casting. It is also possible to use only aluminium for final deoxidation and then add deoxidation.
2. The shell material should be selected reasonably to ensure its quality.
The raw materials can only be put into the warehouse after passing the incoming inspection. The raw materials in stock shall be rechecked regularly, and the unqualified surface material aluminum castings shall not be used by the manufacturer.
3. Choose a reasonable baking technology and strictly implement.
The baking quality of the shell can be judged by the appearance color of the shell. If the shell is dark gray, it means that there is more carbon in the shell, which means that the shell is not completely baked through; if the inner surface or part of the shell is white, powdery white or pink, it means that the baking through quality is good.