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Abstract:   (56 Views)
Track rollers used in bucket wheel excavators are subjected to repeated mechanical loading in an environment where abrasive particles, moisture and corrosive contaminants can accelerate surface deterioration. The present study examines the mechanical, electrochemical and tribological behaviour of GS‑42CrMo4V cast steel used for this application. The material w::as char::acterized through chemical composition analysis, microhardness measurement, tensile testing and fractographic examination. Its corrosion behaviour was further evaluated in 3.5 wt.% NaCl and acidic HCl and H₂SO₄ solutions using potentiodynamic polarization and electrochemical impedance spectroscopy, while three-body abrasion and reciprocating wear tests were carried out to assess its resistance to material loss under different contact conditions. The bottom roller exhibited an average microhardness of 430 HV, compared with 314.2 HV for the roller pin. Tensile and fractographic observations indicated good mechanical performance, although localized damage features were observed on the fractured surfaces. The electrochemical results showed that the material performed better in the neutral chloride solution than in the acidic media. In 3.5 wt.% NaCl, the corrosion current density and corrosion rate were 1.597 μA cm⁻² and 0.487 mpy, respectively, whereas the acidic solutions produced considerably higher corrosion activity. The wear tests confirmed that high hardness alone did not prevent material removal under abrasive and sliding contact. Abrasive action, plastic deformation and localized adhesive interactions contributed to surface degradation under the investigated conditions. The results therefore indicate that, despite its favourable hardness and mechanical characteristics, GS-42CrMo4V remains susceptible to degradation in aggressive acidic environments and under severe abrasive and sliding conditions. The observed behaviour points to the need for further improvement in material processing, surface condition, corrosion protection and the control of abrasive particle ingress. These findings provide a basis for understanding the service-related limitations of the material and for improving the durability of track rollers used in mining equipment.
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