Knowledge of surface machining and solidification

Apr 30,2024


The surface of finely machined parts will have many gray-black circular shallow pits. Before the equipment is cleaned, these pits are filled with slag material, which can directly affect the quality of our castings.

Finely machined processing is convenient, using less material, and can save resources during operation. Many casting methods can only produce relatively simple castings, while another advantage of finely machined processing is the ability to cast complex parts.

There are many issues to pay attention to during finely machined processing, due to the poor fluidity of the molten steel. To effectively prevent defects such as cold shuts during processing, the wall thickness of finely machined parts should not be less than 8mm.

The solidification methods for finely machined processing are as follows:

1. Intermediate solidification: Most alloys solidify between layer-by-layer solidification and paste-like solidification.

2. Paste-like solidification: The crystallization temperature range of alloys is very wide. During a certain period of solidification, there is no solid layer on the surface of the finely machined part, and the solidification zone penetrates the entire cross-section, first becoming paste-like and then solidifying.

3. Layer-by-layer solidification: In the solidification process of metals and eutectic alloys, there is no solidification zone. The liquid and solid phases are clearly separated by a boundary, and as the temperature decreases, the solid phase layer continuously increases while the liquid phase layer continuously decreases.