The investigation of the effects of spray parameters on the thermal and mechanical properties of 22MnB5 steel during hybrid quenching process

Abstract

In this paper, the investigation of the effects of spray parameters on the thermal and mechanical properties of 22MnB5 steel during the hybrid quenching (HQ) process was performed. The HQ method presented in this study includes early removal of hot-stamped parts from the die and transfer to an external multinozzle spray cooling device. The proposed method was developed due to the need for improving disadvantages of the traditional hot stamping process such as complexity of controlling the cooling rate during die quenching by using cooling channels and of providing the reduced tool contact surface temperature after a certain cycle of the hot stamping process. This paper focuses on the temperature distribution and mechanical characteristics of high-strength 22MnB5 steel during the HQ process. Moreover, the methodology developed in this paper can be used to get tailored parts where the cooling rates are locally chosen to achieve structures with graded properties, i.e., to allow local modification of final mechanical properties in order to provide high energy absorption to enhance the crashworthiness of the whole component and thus to improve the vehicle safety performance. The three-dimensional numerical model of spray cooling was also developed by using the computational fluid dynamics (CFD) method to get the suitable process parameters such as spray height and initial blank temperature and to present the detailed heat transfer analysis of hot-stamped parts during the hybrid quenching process.