Direct Quenching After Forging and Inductive Re-heating—A New Efficient Process Technology

The biggest challenges for the forging industry at present are the general economic situation and the growing demands of environmental protection. Therefore, an efficient process using process heat for sustainable production is increasingly indispensable. One possibility is the combination of forging and quenching, the so-called quenching from the hot deformation heat. For more than ten years, this process has been established at BGH Edelstahl Siegen GmbH for many steels. However, this method cannot be applied to steels in which the forging end temperature is below the required quenching temperature. Thus, the process cannot be used for duplex and austenitic stainless steels due to the high solution annealing temperatures. In order to use this approach also for these steel grades, the process has been extended to include the option of inductive reheating. After forging, it is possible to raise the temperature to a required range to quench the material. This process is much faster and more effective than in a standard furnace. This process leads to several advantages in terms of product quality, such as precipitation states, mechanical properties, and residual stresses. The paper gives an overview of the industrial installation of the developed induction re-heating system.