Serious damage to the inner rim of the rear twin wheel in one dump truck was noted during the operation of the fleet performing transport tasks. It was a drive wheel, and its damage occurred while driving with a load exceeding the permissible value. The examination of selected fragments of the damaged rim surface was conducted visually as well as using a digital microscope with a portable head. The measurements of the Vickers hardness and microscopic observations of the material structure of the sample cut along the thickness of the rim disk were carried out. The drive torque loading of the twin wheels of the tipper-truck rear axle, under their mating with different kinds of road roughness and under various vertical loads of the wheels was calculated. An analysis of stress distributions in the rim modelled using the Finite Element Method was also conducted for several possible scenarios of wheel loading. The damage to the rim was caused by simultaneous action of several factors, such as overloading the car, poor condition of the tires, loading the drive wheel by a part of the vehicle weight and the driving torque, and hitting a wheel on a cavity in a dirt road, causing a temporary relief of one of the tires on a twin wheel.

The paper discusses the reasons for the current trend of substituting ductile iron castings by aluminum alloys castings. However, it has been shown that ductile iron is superior to aluminum alloys in many applications. In particular it has been demonstrated that is possible to produce thin wall wheel rim made of ductile iron without the development of chills, cold laps or misruns. In addition it has been shown that thin wall wheel rim made of ductile iron can have the same weight, and better mechanical properties, than their substitutes made of aluminum alloys.

A TiC-Mo ₂C-WC-Ni alloy cermet was fabricated by high-energy ball milling (HEBM) and consolidation through spark plasma sintering. The TiC-based powders were synthesized with different milling times (6, 12, 24, and 48 h) and subsequently consolidated by rapid sintering at 1300°C and a load of 60 MPa. An increase in the HEBM time led to improved sinterability as there was a sufficient driving force between the particles during densification. Core-rim structures such as (Ti, W)C and (Ti, Mo)C (rim) were formed by Ostwald ripening while inhibiting the coarsening of the TiC (core) grains. The TiC grains became refined (2.57 to 0.47 µm), with evenly distributed rims. This led to improved fracture toughness (11.1 to 14.8 MPa·m ^1/2) owing to crack deflection, and the crack propagation resistance was enhanced by mitigating intergranular fractures around the TiC core.