The figure shows the solidification fraction of the sand casting frame at different times. It can be seen that the solidification starts from the external bulge and edge of the column of the sand casting frame. The solidification speed of the part where the cold iron is set in the sand casting frame is faster, the feeding channel is disconnected from the middle of the large and small risers where the cold iron is set, and the large and small risers are finally solidified, It takes about 30 hours to complete solidification of the sand casting frame.
At about 8 hours, the feeding channel in the middle of the column began to disconnect, and at 9 hours, the feeding channel on the other side was also disconnected. Since then, the column part of the sand casting frame is fed by the small riser, and most of the thickness of the beam is supplemented by the large riser. The small riser solidifies before the large riser. It will take about 30 hours for the central part of the large riser to completely cool down. At this time, the frame of sand casting is completely solidified.