There are presented the results of an experimental research developed by authors referring to „U” section bars solidification. The U bars represent a special case of castings. Their solidification and the hot spots position is much influenced by the crossing piece length respective of the distance between the parallel walls. There were realised simulation researches and experimental researches that consist in casting parts and simulating their solidification. The case of casting parts in grey cast iron was analyzed. There were compared the shrinkage positions evidenced in experiments with the hot spots position obtained by solidification simulation on computer. Some conclusions about the validity of the results obtained by solidification simulation are revealed.