High speed impact cutting (HSIC) of advanced high strength steel 42SiCr under exploitation of adiabatic shear bands

Abstract

Abstract Shear Cutting of Advanced High-Strength Steels poses technological challenges due to the substantial mechanical loads imposed on cutting tools, leading to elevated wear rates. A strategy for cutting high-strength materials involves the utilization of high-speed impact cutting (HSIC), wherein component separation occurs along a locally adiabatically heated shear band, resulting in reduced cutting forces. The steel alloy 42SiCr undergoes heat treatments involving Quenching+Tempering (Q+T) as well as Quenching+Partitioning (Q+P) for two sheet thicknesses. This results in the formation of martensitic microstructures with varying retained austenite content, as determined through X-ray Diffraction (XRD). Subsequently, the heat-treated steel samples are subjected to tensile testing for mechanical property evaluation, revealing ultimate tensile strengths exceeding 1500 MPa and fracture elongations ranging from 2 % to 12 %. Following this, the material is subjected to HSIC using the AdiaPress Adia 7 machine, employing predefined cutting energies. It is observed that both Q+T and Q+P-treated materials can be successfully cut using HSIC, although distinct cutting edge morphologies are evident. Optical examinations of the cut edges, conducted through top-view and cross-sectional analysis using Scanning Electron Microscopy and 3D laser scanning microscopy, confirm the presence of adiabatic shear bands and discrete zones.