Despite of the permanent progress of technique and finding of the new, modern materials that successfully replace metals, steel continues to play an important role in the technical practice. The...

The influence of various process parameters on the deep drawing process is a current research topic in sheet metal forming technology. Starting from the application of the previously constructed original testing device, an original tribological model was developed based on the process of sheet metal strip sliding between flat contact surfaces under variable pressures. A complex experiment was executed using an Al alloy sheet, tool contact surfaces of different roughness, two types of lubricants and variable contact pressures. The procedure included analytically pre-defined contact pressure functions based on which, for each of the mentioned conditions, the dependencies of the drawing forces and friction coefficients were obtained. The pressure in function P1 constantly decreased from a high initial value until the minimum, while in function P3 the pressure increased until the minimum value at the halfway point of the stroke, after which it increased up to the initial value. On the other hand, the pressure in function P2 constantly increased from the initial minimum value until the maximum value, while in function P4 the pressure increased until reaching the maximum value at the halfway point of the stroke, after which it decreased to the minimum value. This enabled the determination of the influence of tribological factors on the process parameters of intensity of traction (deformation force) and coefficient of friction. The pressure functions starting with decreasing trends produced higher values for the traction forces and the friction coefficient. In addition, it was established that the roughness of the contact surfaces of the tool, especially those with titanium nitride coating, has a significant influence on the process parameters. For surfaces of lower roughness (polished), a tendency of the Al thin sheet to form a glued-on layer was noticed. This was especially prominent for lubrication with MoS₂-based grease under conditions of high contact pressure (functions P1 and P4 at the beginning of the contact).

Despite the development of the new, modern non-metallic materials, the steel materials are largely used in various branches of industry, while in some applications they are still irreplaceable. It is expected that such a trend will remain for certain number of years. This is why the necessity is present for development of the new types of steels, which would possess even better properties. The Chromium-Molybdenum (Cr-Mo) steels, with high vanadium content, belong to the group of newer steels characterized by high values of hardness and toughness. In this research, the tests were performed on samples made from the X180CrMo12-1 steel with varying percentage of vanadium within the limits of 0.5-3%. Vanadium, as a carbide-forming alloying element, creates a carbide network of the M7C3 type around the metal matrix, and finely dispersed carbides of the V6C5 type within the metal matrix. This research was focused on determining the carbides’ composition, observing the shape of metal grains and carbide network, testing the material’s resistance to friction and wear, including the electrochemical characterization, as well. The objective was to determine the carbides microstructure and morphology, as well as to evaluate their impact on the material's characteristics. The experimental investigation was performed using the scanning electron microscopy with energy dispersive spectrometry (SEM-EDS) and X-ray diffractometric analysis (XRD). Examination of the carbide composition confirmed that it was the M7C3 carbide.