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This paper deals with material and dimensional bending analysis of bimetallic pipes with defined bending radii. Basic characteristics of selected nickel superalloys with analysis of Inconel 625 and 16Mo3 steel in terms of primary mechanical properties and chemical composition are presented. In the practical part where the bimetallic tube is analyzed in terms of material properties is also performed geometric dimensional analysis, for which test specimens with different bending radii are made. The capillary test preceded dimensional analysis to remove cracks on the outer bend surfaces of the bimetallic tube. The geometric dimensional analysis itself is carried out using a 3D scanner and also includes external dimensional inspection in longitudinal section with changes in the curvature of bimetallic pipe bends for different bending radii. The article concludes with an overall evaluation of the achieved results, especially with regard to the deviations of rounding in individual sections of the external dimension.

This article deals with the effect of selected machining parameter values in hard turning of tested OCHN3MFA steel in terms of SEM microstructural analysis of workpiece material, cutting forces, long-term tests, and SEM observations of flank wear VB and crater wear KT of used changeable coated cemented carbide cutting inserts in the processes of performed experiments. OCHN3MFA steel was selected as an experimental (workpiece) material. The selected experimental steel was analyzed prior to hard turning tests to check the initial microstructure of bulk material and subsurface microstructure after hard turning and chemical composition. Study of workpiece material’s microstructure and worn cemented carbide cutting inserts was performed with Tescan Vega TS 5135 scanning electron microscope (SEM) with the X-Ray microanalyzer Noran Six/300. The chemical composition of workpiece material was analyzed with Tasman Q4 surface analyzer. All hard turning experiments of the used specimens were performed under the selected machining parameters in the SU 50A machine tool with the 8th selected individual geometry of coated cementite carbide cutting inserts clamped in the appropriate DCLNR 2525M12-M type of cutting tool holder. During the hard turning technological process of the individual tested samples made of OCHN3MFA steel, cutting forces were measured with a Kistler 9257B piezoelectric dynamometer, with their subsequent evaluation using Dynoware software. After the long-term testing, other experiments and results were also realized, evaluating the influence of selected machining parameters with different cutting insert geometry on the achieved surface quality.

The goal of the submitted paper is to evaluate the dependence of tool life T = f(vc) in hard rough face milling process of the Armox 500 steel through the PVD coated cemented carbide cutting material with SNHF 1204EN-SR-M1 tool insert geometry. Practical tests of choice material were performed in the milling machine tool with vertical axis. The effect of applied cutting conditions on the surface finish, tool life, wear of cutting tool, such as flank wear and surface structure of applied cutting inserts, was investigated during the performed experiments. The goal of this article is to research the impact of various cutting speeds values during the process of hard face rough milling. Experiments are carried out with an aim to study tool life, surface finish and flank wear prediction on the PVD coated cemented carbide cutting material in hard milling processes. This has been observed through the REM and mathematical method of least squares for this characterization. The presented approach and acquired results will prove themselves helpful in understanding the machinability of Armox 500 steel during the hard milling process.

Tool steels are used in technological processes of forming and cutting and as cutting tools due to their good mechanical properties. During their working cycle, steels are exposed to several aggressive conditions, such as thermal stress, fatigue and various forms of wear. In this article, the selected 90MnCrV8 tool steel slid against the Si3N4 testing ceramic bearing ball. All measurements were performed on a universal tribometric device UMT TriboLab (TA Instruments, New Castle, Delaware, USA) under dry conditions. The main objective of the performed experiments was to analyse the frictional properties and compare the wear of the 90MnCrV8 tested tool steel in contact with the 6.35 mm diameter ceramic ball at different friction speeds. In this measurement evaluation, the authors of the article mainly focused on the influence of the magnitude of the peripheral speed on the wear change and coefficient of friction. Further analysis was focused on the change of surface roughness of the counterpart ceramic balls as well as of the tested tool steel samples. Experimental results show the fact that tested tool steels, which can also be considered as high strength steels, can also successfully represent wear-resistant steels. It has been shown experimentally that increasing the friction speed also leads to significant degradation of the material on the sample surface. Finally, the effect of hardness on wear has also been experimentally demonstrated. The Si3N4 ceramic ball with its high strength also behaves like an abrasive, thus increasing the wear rate on the experimental tool steel samples.