In this paper, the subject of the analysis is Rotinger High Performance brake disc, characterized by increased thermal resistance, which is a result of adequate design and material solutions. However, despite declared performance, the analyzed discs suffered accelerated wear over a period of about 20 months. The aim of this study was to assess the causes of the disc failure. As a result, it was showed that the applied material solution still does not differ from standard ones. According to the authors of this paper, an appropriate procedure to improve resistance to thermal fatigue is, among others, changing the shape of graphite precipitates from flake to spheroidal.
This paper presents an analysis of six sets of engine valves, each set consisting of one exhaust valve and one intake valve. Each pair of valves was used in an engine with different displacement and mileage. The valves were subjected to microscopic analysis, hardness measurement and chemical composition analysis using a glow discharge spectrometer and energy dispersive spectroscopy (EDS). The design and materials of the valves showed that both the intake and exhaust valves in their present form would be a strength of the engine.
Hadfield steel, under unit pressure conditions, strengthens itself by forming a high density dislocation structure, which results in increased resistance to dynamic impact wear. However, under abrasion conditions, the homogeneous microstructure of the cast steel is insufficient to achieve the expected service life. The aim of the research is to conduct a comparative analysis of the material in its as-delivered state and after two-stage heat treatment (isothermal annealing followed by re-austenitisation). It was found that after isothermal annealing of X120Mn12 grade steel at a temperature of 510 °C, a microstructure with a complex morphology consisting of colonies of fine-grained pearlite, (Fe,Mn)3C carbides distributed along the grain boundaries of the former austenite and needle-like (Fe,Mn)3C carbides was obtained in the austenite matrix. The subsequent thermal treatment of the steel with the use of supersaturating annealing at 900 °C resulted in a heterogeneous microstructure consisting of evenly distributed globular carbide precipitations in a matrix of considerably finer austenite grains in comparison with the as-delivered original state. As a result of the final microstructural changes achieved, a 16.4% increase in abrasion resistance was obtained compared to the delivered condition.
Safety belts are one of the most significant elements of car equipment classified as passive safety. This paper provides a comparative material analysis of critical components of a trusted manufacturer's six-point harness used in motorsports racing with commercially available imitation belts. Despite the FIA certification labels, the imitation belts are characterized by extremely poor quality in the selection of materials for components such as the snap hooks and the locking sleeves in the central fastening mechanism, posing a real hazard to unaware belt users. At the same time, the results of the research are also intended to build consumer awareness of the risks associated with the purchase of passive safety equipment from unreliable sources or/and at discount prices, which entails real threats to life and health.
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