PSI - Issue 81

Viktor Kovalov et al. / Procedia Structural Integrity 81 (2026) 346–352

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WC/Co interfaces and consume a substantial fraction of fatigue life. These findings are consistent with broader reviews highlighting the decisive role of surface and subsurface defects, residual stresses, and multiaxial loading in controlling fatigue crack growth resistance. Surface engineering and hard coatings also influence crack initiation and propagation in carbide tools. Modern PVD and CVD multilayer coatings can delay the formation of radial and ring cracks and reduce the likelihood of coating delamination (Panjan et al.; Musil, 2014; Calderón et al., 2020). Tribologi cal studies further indicate that under severe cutting loads, crack initiation in coatings often precedes substrate damage and is closely linked to local thermo-mechanical conditions at the tool – chip interface (Amar et al., 2012; Tribology International). In recent years, pulsed and static magnetic fields have attracted increasing attention as a means of improving crack resistance and reliability of metallic and hard-metal systems. Hu et al. (2022) showed that magnetic-field-assisted processing can modify microstructure and residual stress states, leading to improved fatigue behaviour. Zhang et al. (2022) reported increased bending strength, hardness, and cutting life of cemented carbide tools treated by a pulsed magnetic field, which was attributed to relaxation of residual stresses and reduced defect density. Similar effects have been reported for electromagnetic- and magnetic-field-assisted treatments (Zhan et al., 2024), indicating that magnetic fields can influence early stages of crack initiation. Alongside these material-based approaches, probabilistic and degradation-based models have been applied to describe the stochastic nature of tool wear and failure (Huang et al., 2021; Gao et al., 2022; Asgari et al., 2024). Data-driven and hybrid PHM approaches further support tool condition monitoring and reliability assessment (Salonitis et al., 2014; Tiwari et al., 2023; Zhang et al., 2022). However, many of these studies are based on simplified laboratory conditions and do not explicitly address crack evolution in real modular inserts under heavy-duty cutting. Despite this progress, systematic experimental studies quantifying the effect of pulsed magnetic field treatment on the durability, reliability, and tool life scatter of cemented carbide inserts under real heavy machining conditions remain limited. In particular, the influence of PMFT on crack-related failure mechanisms in modular tools subjected to complex, non-stationary thermo-mechanical loading has not been sufficiently investigated. This constitutes an important research gap for industrial heavy turning applications. The objective of this study is to experimentally investigate the effect of pulsed magnetic field treatment on the operational durability and reliability of cemented carbide cutting inserts used in heavy turning. The novelty of this work lies in the application of PMFT to real cutting inserts combined with a systematic evaluation of tool life, crack-related failure modes, and statistical scatter under severe cutting regimes. The main contributions of this study are: • experimental implementation of pulsed magnetic field treatment for cemented carbide cutting inserts; • quantitative assessment of tool life and its variability under heavy machining conditions; • analysis of crack -related failure mechanisms and their relation to magnetic field treatment; • demonstration of the potential of PMFT to improve tool reliability and process stability. The practical significance of the results is associated with increasing tool life, reducing premature failures, and improving the predictability of tool performance in heavy machining applications. The paper is organized as follows. Section 2 describes the experimental materials, pulsed magnetic field treatment procedure, and testing methodology. Section 3 presents and discusses the experimental results. Finally, Section 4 summarizes the main conclusions and outlines directions for future research. 2. Experimental and Research Methods Experimental investigations were carried out using cemented carbide cutting inserts of industrial grades T5K10, T15K6, VK3, and VK8, which are widely applied for heavy machining operations. The inserts were used in both brazed and indexable configurations typical for heavy-duty turning in machine-building applications. Both untreated (reference) and modified inserts were investigated. Pulsed magnetic field treatment (PMFT) was applied as a bulk modification method. The treatment was performed using a compact pulsed magnetic field generator producing short-duration, high-intensity magnetic field pulses. The PMFT process was based on magnetostrictive and electromagnetic effects, leading to relaxation of internal stresses, modification of defect structure, and redistribution of microstresses in the cemented carbide material. The treatment was applied to inserts made of grades T5K10, T15K6, VK3, and VK8 under regimes selected to ensure stable strengthening without thermal damage to the tool material. The bending strength of cemented carbides was evaluated in accordance with ISO 3327, ASTM B406, and GOST 20019-74 using three-point and four-point bending configurations on standard prismatic specimens. To assess the actual constructional strength of cutting inserts, an original experimental method was applied based on testing of miniature cantilever beams fabricated directly on real cutting inserts using electrical discharge machining. Longitudinal and transverse micro-notches were introduced to form single- and multi-level systems of miniature cantilever beams in the cutting edge region. Each beam was sequentially loaded in bending until fracture, and the local bending strength was determined using the classical cantilever beam equation based on the measured fracture load and beam geometry. This approach enabled local evaluation of strength, defect distribution, and damage state in different regions of the cutting edge, which cannot be captured using standard bulk specimens. Laboratory and industrial cutting tests were performed on heavy turning machines, including models KZh.16274F3, 1A670F3, and 1A64. Tool life and failure behavior were evaluated under heavy turning conditions using destructive feed methods and