This doctoral thesis deals with the production of high-strength, quenched and tempered heavy plates. The first part describes the creation of statistical models by which properties can be calculated from the chemical composition and the cooling rate from austenitisation temperature. These properties can be phase transformation temperatures or the hardness of quenched or quenched and tempered probes which were treated in the dilatometer. It is shown in this work that the models for calculating the hardness of probes treated in the dilatometer are also suitable for predicting tensile strength of laboratory made plates. As explained in the work, the created models can be used to design new alloys with specific requirements for strength or to optimize existing alloys through the exchange of alloying elements regarding the costs. Since the influence of alloying elements on the strength properties is known at different cooling rates from austenitization temperature, the influence of a scattering chemical composition within a steel grade on the mechanical properties can be reduced by adapting the cooling rate. Because of that production safety can be increased. The second part of this doctoral thesis deals with the improvement of the toughness properties for high-strength heavy plates. Beside the addition of larger amounts of nickel, improvements can also be achieved by optimizing the parameters of the existing processes. Due to a new process in heavy plate production, toughness can be improved significantly. In the Charpy impact test, for example, the brittle-to-ductile transition temperature can be lowered to a temperature below -120°C for a plate with a yield point of about 850 MPa.