Cracking is a major problem for some types of steel during additive manufacturing. Non-equilibrium kinetics of rapid solidification and solid-solid phase transformations are critical in determining cracking susceptibility. Previous studies correlate hot cracking susceptibility to solidification sequence, and therefore composition, empirically. In this study, an Integrated Computational Materials Engineering (ICME) approach is used to provide a more mechanistic and quantitative understanding of hot cracking susceptibility of a number of steels in relation to the peritectic reaction and evolution of delta ferrite during solidification. In this presentation, the application of ICME and hot cracking susceptibility predictions to alloy design for additive manufacturing are discussed.