Abstract
In order to investigate the solidification cracking susceptibility of alloy tool steel under rapid solidification, the cracking behaviors were dynamically observed with the high speed camera. It was clarified from the experimental results that the reduction of Si, and P content can decrease the susceptibility in the indexes of the minimum ductility (εmin), the critical strain rate for temperature drop (CST) and Brittle Temperature Range (BTR). This could be explained by the behavior of liquid phase estimated by the microsegregation model. It is understood that the film like region at the last stage of solidification was finished early due to the reduction of segregation. Therefore, the reduction of Si and P content can be effective in decreasing the risk of solidification crack.
