What is the mechanism that affects the hollowing of low pressure casting molds?

During low pressure casting, die wall thickness may be uneven due to the morphological characteristics of the casting and other factors. If the local heat dissipation of the mold is not good, the cooling of the casting is unbalanced, which will disrupt the sequential solidification of the casting, resulting in shrinkage and porosity. The occurrence of defects.

There is an isolated liquid phase region, which is prone to shrinkage and shrinkage defects. There is an isolated liquid phase region throughout the solidification process; shrinkage cavities and porosity are prone to occur according to the criteria of residual melt modulus.

There is an isolated liquid phase region at four locations in the curing sequence; shrinkage cavities and porosity are prone to occur according to criteria for residual melt modulus.

During the filling process, the temperature of the molten metal drops a lot, and defects of insufficient pouring may occur.

Under the premise that the initial plan analysis is highly consistent with the benchmark, we have improved the mold hollow plan. Used to simulate the casting process of the hollowed mold and focus on observing the original defect.

The solidification sequence results show that the defects can be improved to a certain extent by hollowing out the mold. The temperature field is greatly improved, and the defects can be solved.

To further understand the mechanism of mold hollowing, set the temperature sensors at the same location in the two sets of molds and hollow them out without hollowing them out.

Comparing the temperature results, it can be concluded that when the temperature of the cyclic production mold is stable, the initial temperature of the unemptied mold is about 410 ° C, while the empty mold is about 450 ° C. Comparing the temperature results of these six measurement points on line A, it can be concluded that when the temperature of the cyclic production mold reaches a stable level, the initial temperature of the empty mold is smaller than the empty mold temperature. Comparing the temperature change results of these six measurement points in range B, it can be concluded that the temperature change range of the empty mold is larger than that of the hollow mold. The hollow mold has better heat storage capacity.

After the mold is hollowed out, the heat dissipation capacity of the local thin-walled area of the mold is improved, which can effectively change the change of the temperature field of the casting in the early stage of solidification, thereby controlling the solidification casting to the design direction. After the mold is hollowed out, for the entire mold, the hollow in continuous casting has obvious heat storage capacity for the mold. It ensures the mold temperature requirements before casting.