Due to the thick section structure and long solidification time of sand casting frame steel castings, the stress field in the process of solidification and cooling needs to be analyzed. The stress field analysis of frame sand casting process mainly includes thermal stress field analysis of solidification process, residual stress analysis of cooling process and deformation analysis of solidification cooling process.
The equivalent stress distribution diagram of each part of the sand casting frame at different temperatures is shown in Figure 1, in which figure D is the stress distribution diagram when the frame is completely solidified. In the whole solidification process, the equivalent stress of sand casting is between 0-50mpa. Due to the earliest cooling, the stress increases fastest at the fillet of the convex part of the sand casting.
With the progress of solidification, the stress at the fillet inside the window of the sand casting frame begins to increase, and its value is between 25-35mpa until the end of solidification; In the middle stage of solidification, the stress value at the bottom of large and small risers begins to increase, and the increasing speed of the stress value at the root of large riser is significantly greater than that at the root of small riser. At the end of solidification, the stress value at the root of large riser is about 40MPa, while the stress value at the root of small riser decreases gradually, about 20MPa.