to shakeout (at 50 ◦C) was released by the shakeout process, and the greater restraint forces that occurred just before shakeout resulted in the larger released deformation in the castings. This finding can be confirmed by comparing the free-to-experimental contraction difference curves of the large flange casting and the small flange casting in the furan sand mold, as shown in Fig. 6. These findings indicate that the increase in the free-to-experimental contraction difference below 250 ◦C is due to elastic deformation. Following this proposed mechanism, the mechanical interaction between the
casting and the sand mold under the relatively high restraint force conditions can be explained by the following process.