Wpływ ilości wprowadzonego ciepła na jakość i właściwości dwuimiennych złączy doczołowych ze stali o podwyższonej wytrzymałości

The paper presents the results of non-destructive and destructive tests of dissimilar high-strength low-alloy S460ML and S460N steel butt joints. These steels are characterized by similar mechanical properties, but their carbon equivalent CeIIW values are much different. The joints were made using different values of heat input for each welding bead. They were tested by non-destructive methods: visual, penetrant, radiographic and ultrasonic tests. Then, the destructive tests were made: static tensile test, bending test, impact test and Vickers HV10 hardness measurements. The results of prepared examinations showed, that welding with higher heat input has significant impact on the mechanical properties of the dissimilar steel joints - the joint welded with bigger heat input was characterized by better mechanical properties.W pracy przedstawiono wyniki badań niszczących i nieniszczących dwuimiennych złączy doczołowych wykonanych ze stali o podwyższonej wytrzymałości o zbliżonych właściwościach mechanicznych S460ML i S460N, które znacząco różnią się wartością równoważnika węgla CeIIW. Złącza wykonano z zastosowaniem różnych wartości ilości wprowadzonego ciepła dla poszczególnych ściegów. Zostały one poddane badaniom nieniszczącym: wizualnym, penetracyjnym, radiograficznym oraz ultradźwiękowym. Następnie wykonano statyczną próbę rozciągania, próbę gięcia, badania udarnościowe oraz pomiary twardości metodą Vickersa HV10. Wyniki badań pokazały, że spawanie większą energią liniową ma znaczący wpływ na własności mechaniczne złączy badanych stali - złącze wykonane wyższymi wartościami charakteryzowało się lepszymi własnościami mechanicznymi

Application of Rapid Prototyping Technology in the Manufacturing of Turbine Blade With Small Diameter Holes

The article presents the possibilities++ of using Rapid Prototyping (RP) technology in the manufacturing of turbine blades with small diameter holes. The object under investigation was gas turbine blade with small diameter cooling holes and holes for generating longitudinal vortices. A turbine blade model was produced by means of Direct Metal Laser Sintering (DMLS) technology and subsequently validated in terms of detection and accuracy of the obtained holes. The application of the computer tomography and digital radiography technique resulted in obtaining a series of cross-sections of the turbine blade model with a series of holes. Particular attention was pointed out at the investigation of the locations of micro-holes with a diameter of 0.3 mm. It turned out that it was impossible to make such small holes by the RP method. In the following part the results of the study on the possibilities of making the micro-holes using electrical discharge method have been presented. In addition, proposition of further works such as the development of the considerations and issues discussed in this article, has been offered

Organic Vapor Sensing Mechanisms by Large-Area Graphene Back- Gated Field-Effect Transistors under UV Irradiation

The gas sensing properties of graphene back-gated field-effect transistor (GFET) sensors toward acetonitrile, tetrahydrofuran, and chloroform vapors were investigated with the focus on unfolding possible gas detection mechanisms. The FET configuration of the sensor device enabled gate voltage tuning for enhanced measurements of changes in DC electrical characteristics. Electrical measurements were combined with a fluctuation-enhanced sensing methodology and intermittent UV irradiation. Distinctly different features in 1/f noise spectra for the organic gases measured under UV irradiation and in the dark were observed. The most intense response observed for tetrahydrofuran prompted the decomposition of the DC characteristic, revealing the photoconductive and photogating effect occurring in the graphene channel with the dominance of the latter. Our observations shed light on understanding surface processes at the interface between graphene and volatile organic compounds for graphene-based sensors in ambient conditions that yield enhanced sensitivity and selectivity