In the die casting field there are more and more larger tool dimensions in service, at which nowadays die casting moulds reach a very high proficiency level. To achieve good property profiles a good tensile strength while maintaining sufficient toughness is necessary. This was the reason for the company Böhler Edelstahl & Co KG to develop alloying concepts. Moreover, the alloys should exhibit a good hardening capacity and should be cost-efficient. Typical applications of these hot-work tool steels are die casting moulds for structural components in the automobile industry. The goal of the present project was to conduct a characterisation of the properties of four different hot-work tool steels. Moreover, a comparison to nowadays used hot-work tool steels was done. To characterise the alloys hardness-temper curves were determined. To get the necessary heat treatment parameters, dilatometric quenching tests, carbide analyses and grain size analyses were performed. In order to show γ/α change characterisitcs, four time-temperature transformation diagrams were established. To investigate the ductility, impact tests on samples that had already been quenched and tempered were made. The results could be illustrated about the chemical composition. The indicated hardening temperature and the course of the hardness-temper curves is the reason for this statement. Depending on the chemical composition the position and the level of the secondary hardening peak as well as the hardening temperature were different. Also the results of the time-temperature transformations diagrams showed that the chemical composition is responsible for the shift of the bainitc transformation to longer times.