Analysis of the spreader track wheels premature damages

The superstructure of the ARs 2000 spreader leans on three crawlers of identical length, width and height. Serious damage to the track wheels threads occurred already during the spreader’s travel from the erection site to the open pit mine as well as immediately after the overburden system exploitation started. The goal of the study presented in this paper was to diagnose the cause of the track wheels premature damage. Contact stresses on the track wheel bearing surface are defined by applying Hertz’s theory and FEM. In order to clarify the causes of the damages, experimental investigations were performed with the purpose of defining the chemical composition, tensile properties, impact toughness and macro and microhardness of the track wheel material. Metallographic examinations were also conducted. Based on the results of the analytical–numerical–experimental analysis, it can be concluded that track wheels failures are predominantly caused by the ‘design-in’ and ‘manufacturing-in’ defects.

► The original procedure of wheel static overstressing is presented.
► Calculated contact stress level exceeds the permissible values.
► Material tensile and impact properties were lower than required.
► Primary heat treatment was done on too high a temperature.
► Damages were caused by ‘designing-in’ and ‘manufacturing-in’ defects.