This article discusses the subtleties of spray quenching in induction surface hardening (case hardening) and selective hardening applications utilizing scanning and single-shot heating modes. Computer modeling provides the ability to predict how different factors may impact the transient and final heat-treating conditions of the workpiece and what must be accomplished in the design of the induction heating system to improve the effectiveness of the process and guarantee the desired results. One of the major features of computation of induction hardening processes deals with the specifics of modeling, i.e., both heating and quenching stages that can often be overlapped in time. Water or water-based polymers are the most popular types of quenchants used with induction hardening. Results of computer modeling of different induction hardening applications, using Inductoheat's proprietary finite element codes, are presented here as well.