An approach for a reliable detection of grinding burn using the Barkhausen noise multi-parameter analysis

Abstract

High loaded, case-hardened workpieces are often finished by grinding to meet required form tolerances and generate high-quality surfaces. The thermo-mechanical load during grinding influences the surface integrity and therefore the functional behavior of the workpieces. To increase productivity, grinding processes are often operated at their limit. Therefore, already even minor deviations from the desired process conditions can lead to thermo-mechanical damages, often referred to as grinding burn. Micromagnetic testing methods allow for a nondestructive analysis of the surface integrity of ground workpieces. Often, a combination of multiple parameters is used to get distinct results. In this study, the Barkhausen noise measurement was used for a nondestructive characterization of process specific influences on the surface integrity in order to further improve the grinding burn detection. Case-hardened workpieces made of AISI 4820 steel were finished by outer diameter grinding with varying specific material removal rates Q’w in a range of 0.5 mm³/(mm s) to 24 mm³/(mm s). Determining the resulting surface integrity, different levels of thermo-mechanical influence on the workpiece surface layer were detected. A detailed analysis of the effective Barkhausen noise (RMS-value), the Coercivity and the Peak Position was performed in order to evaluate the influence of the magnetization parameters on the resulting signals depending on the surface integrity. A varying sensitivity for indication of thermo-mechanical damages with different magnetization parameters was found. The presented results allow for an improvement of the reliability of the Barkhausen noise multi-parameter grinding burn analysis.