High temperature and dynamic testing of AHSS for an analytical description of the adiabatic cutting process

19th Chemnitz Seminar on Materials Engineering – 19. Werkstofftechnisches Kolloquium

Winter, S.^1 ; Schmitz, F.^2 ; Clausmeyer, T.^2 ; Tekkaya, A.E.^2 ; Wagner, M.F.-X.^1

Institute of Materials Science and Engineering, Chemnitz University of Technology, Chemnitz

09125, Germany^1

Institute of Forming Technology and Lightweight Construction, Technical University of Dortmund, Dortmund

44227, Germany^2

关键词: Adiabatic shear band;    Advanced high strength steel;    Analytical description;    Cutting surface qualities;    High strain rates;    Split Hopkinson pressure bars;    Temperature evolution;    Temperature range;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/181/1/012026/pdf
DOI  :  10.1088/1757-899X/181/1/012026

来源: IOP

【 摘 要 】

In the automotive industry, advanced high strength steels (AHSS) are widely used as sheet part components to reduce weight, even though this leads to several challenges. The demand for high-quality shear cutting surfaces that do not require reworking can be fulfilled by adiabatic shear cutting: High strain rates and local temperatures lead to the formation of adiabatic shear bands (ASB). While this process is well suited to produce AHSS parts with excellent cutting surface quality, a fundamental understanding of the process is still missing today. In this study, compression tests in a Split-Hopkinson Pressure Bar with an initial strain rate of 1000 s-1were performed in a temperature range between 200 °C and 1000 °C. The experimental results show that high strength steels with nearly the same mechanical properties at RT may possess a considerably different behavior at higher temperatures. The resulting microstructures after testing at different temperatures were analyzed by optical microscopy. The thermo-mechanical material behavior was then considered in an analytical model. To predict the local temperature increase that occurs during the adiabatic blanking process, experimentally determined flow curves were used. Furthermore, the influence of temperature evolution with respect to phase transformation is discussed. This study contributes to a more complete understanding of the relevant microstructural and thermo-mechanical mechanisms leading to the evolution of ASB during cutting of AHSS.