Nanostructured cemented carbides with Co binders have shown excellent mechanical properties in various applications. Nevertheless, their corrosion resistance has shown to be insufficient in different corrosive environments, leading to premature tool failure. In this study, WC-based cemented carbide samples with different binders were produced using 9 wt% of FeNi or FeNiCo with the addition of Cr3C2 and NbC as the grain growth inhibitors. The samples were investigated using electrochemical corrosion techniques: the open circuit potential Ecorr, the linear polarization resistance (LPR), the Tafel extrapolation method, and the electrochemical impedance spectroscopy (EIS) at room temperature in the solution of 3.5% NaCl. Microstructure characterization, surface texture analysis, and instrumented indentation were conducted to investigate the influence of corrosion on the micro-mechanical properties and the surface characteristics of the samples before and after corrosion. The obtained results indicate a strong binder chemical composition’s effect on the consolidated materials’ corrosive behavior. Compared to the conventional WC-Co systems, a significantly improved corrosion resistance was observed for both alternative binder systems. The study shows that the samples with the FeNi binder are superior to those with the FeNiCo binder since they were almost unaffected when exposed to the acidic medium.

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The calibration of screw thread gauges is a conventional procedure in calibration laboratories and National Metrology Institutes. Proper measurement and reliable uncertainty analysis of the screw thread gauge calibration are complex and demanding tasks.Different technical documents and international standards in screw metrology define calibration categories, explain measurement plans, measuring elements, nominal diameters and their tolerances, and propose guidelines for the measurement uncertainty estimation. Therefore, the first part of this paper provides a detailed overview of different technical documents and international standards in screw thread metrology.The second part of this paper aims to draw attention to critical points of the pitch diameter calibration procedure that lead to a significant increase in measurement uncertainty. Most calibration laboratories do not measure the thread angle during the pitch diameter calibration. Therefore, the selection of the measurement wires can contribute greatly to the measurement uncertainty.Even though the international standards propose the best size wires to avoid this problem, many manufacturers produce measuring wires according to DIN 2269 (Zeiss). In this paper, the authors do simulations of the contribution of measuring wires to the uncertainty in the calibration of the pitch diameter of metric M threads. A simulation is created for each thread gauge according to ISO 1502, and critical threads, in which a significant increase in measurement uncertainty is expected, are highlighted.The authors propose a simple solution for avoiding this unwanted increase in measurement uncertainty of pitch diameter calibration; the solution involves replacing the DIN 2269 (Zeiss) wires with the best-size wires only for the highlighted critical threads.

<p>This paper describes a laboratory method for the determination of the pressure balance piston fall rate using a simple camera-based optical system with internally developed software. Measurements were carried out on three standard piston/cylinder units in the Croatian National Pressure Laboratory (LPM) using gas and oil as transmitting medium.<br />Measurement equipment, procedure and fall rate results for three sets of measurements are given, as well as an evaluation of the measurement uncertainty. Results were compared with other relevant measurements.</p>

The main condition for the realization of a reinforced concrete construction is a complete coupling between the concrete and steel, used as reinforcement. Using higher quality steel, the force of the reinforcement has been increased and thus the risk of separation of these two materials. To avoid undesirable slip phenomena, great importance is put on the geometrical features of reinforcement steel used, i.e. the main contribution to the total adhesiveness lies in shear adhesiveness of the ribs or profiles on the surface of steel bars. Based on measured geometric features one can calculate a factor called the factor of adhesion or relative rib area. Therefore testing, i.e. concluding about the reliability of the measuring method with respect to the requirements of ISO 15630-1:2002, is the topic of this study. For that purpose measurements were preformed using two methods in order to calculate the factor of adhesion. First method was the optical method, using the instrument RM 302/202 manufactured by ECM Datensysteme GMBH. Furthermore measurements were preformed by the use of conventional length measurement equipment that is commonly available in production, sucs as dial indicators and vernier callipers. The obtained measurement results were subjected to statistical analysis as required by ISO 5725-1984 (E), and based on that the conclusions of the accuracy and reliability of measurement methods were made.