The article presents the results of studies on the influence of simulated thermal cycles parameters on the structure and properties of the heat-affected zone (HAZ) of thermo-mechanically rolled S700MC steel. For this purpose, resistance heating tests of the tested samples were carried out to determine the effect of maximum temperatures of the imposed thermal cycles with different maximum temperatures at a constant cooling time in the temperature range between 800 and 500 °C (t8/5) and to study the influence of changes of this time on the structure and hardness as well as the tensile strength, elongation and toughness of the simulated HAZ in S700MC steel. The results of the tests, were supported by the results of finite element method (FEM) analyses in the VisualWeld (SYSWELD Code) software of the ESI Group. Selected heat distributions during heating, distributions of individual metallurgical phases and hardness were compared with results from real tests. On the basis of the results presented, an attempt was made to explain the decrease in mechanical and plastic properties in the HAZ area caused by the influence of the welding heat cycle.
The article presents research in the field of laser cladding of metal-matrix composite (MMC) coatings. Nickel-based superalloys show attractive properties including high tensile strength, fatigue resistance, high-temperature corrosion resistance and toughness, which makes them widely used in the industry. Due to the insufficient wear resistance of nickel-based superalloys, many scientists are investigating the possibility of producing nickel-based superalloys matrix composites. For this study, the powder mixtures of Inconel 625 superalloy with 10, 20 and 40 vol.% of TiC particles were used to produce MMC coatings by laser cladding. The titanium carbides were chosen as reinforcing material due to high thermal stability and hardness. The multi-run coatings were tested using penetrant testing, macroscopic and microscopic observations, microhardness measurements and solid particle erosive test according to ASTM G76-04 standard. The TiC particles partially dissolved in the structure during the laser cladding process, which resulted in titanium and carbon enrichment of the matrix and the occurrence of precipitates formation in the structure. The process parameters and coatings chemical composition variation had an influence on coatings average hardness and erosion rates.
The following study presents the results of wear-resistant layer made of Ni-Cr-Si-B-Fe-C+WC alloy in the form of metallic powder on the AISI 4715 steel. Hardness and abrasion resistance tests were performed in accordance to PN-EN ISO 6508-1:2016 and ASTM G65-00 standards. Obtained data were compared to the abrasion resistant steel produced by Swedish manufacturer. Microscopic observations were made to determine the structure of obtained layer and base material using Olympus SZX9 stereoscopic light microscope. In order to determine the chemical composition of microregions, X-ray microanalysis researches were carried out.
The article presents results of microstructure, microhardness and geometry tests of cobalt-based alloys deposited on low-alloy steel by a laser cladding process. As a deposited material MetcoClad 6 powder was used. Powder is characterized by a spherical shape of particles obtained in inert gas-atomization process with a size of -106 +45 µm suited to a variety of hardfacing processes. The experiments were carried out using a disk laser Yb:YAG TruDisk 3302, with a wavelength of 1.03um equipped with a disc powder feeder. The laser cladding process was carried out at various parameters of cladding speed, beam power and powder feed rate in order to obtain layers with low dilution, low porosity and good coating uniformity. Macroscopic studies were performed using a metallographic microscope light stereoscopic Olympus SZX9. Vickers microhardness tests were provided on the cross-section of layers on Wilson Wolpert 401 MVD device.
The article describes the effect of alloyed additives in base material and filler metal on intergranular corrosion. Steel 1.2 mm thick, titanium-stabilized ferritic stainless steel and titanium and niobium-stabilized ferritic stainless steel have been surfacing method MAG (135). The specimens received was subjected to macro and microscopic tests, hardness tests and the intergranular corrosion resistance test. The study showed a higher corrosion resistance of niobium and titanium stabilized steel from titanium-stabilized steel. In addition, a ferritic fine-grain structure was found in the padding axis made with the use of filler metal with titanium and niobium microadditives.
The article presents the results of Ti and C additives on the microstructure of the Metcoclad 6 coating. Effect of chemical composition with optimal laser cladding parameters has been studied in the terms of modification of the carbide morphology. The experiments were carried out on TruDisk 3302 Yb:YAG disk, equipped with a disc powder feeder. As a deposited material Metcoclad 6 powder produced in inert gas-atomization process was used. To assess the impact of alloying elements on microstructure, SEM observations and EDS analysis were carried out. Vickers microhardness tests were provided on the cross-section of coatings on Wilson Wolpert 401 MVD device. It has been stated that addition of titanium changes the morphology of carbides from lamellar eutectic carbides to isolated primary TiC while addition of Ti and graphite allowed to maintain the structure typical for pure Stellite 6 alloy, but additional formation of primary carbides were observed.
The article describes the impact of oxygen, HD air plasma and laser beam cutting processes on structural changes and quality of the surface of thermomechanically treated S700MC and heat-treated S690QL steels. Taking into account good quality of obtained cut surface, particular attention shall be attached to the structural and chemical changes due to the impact of the heat cycle. Those modern steels are especially susceptible to a loss of their properties during the heat interaction in thermal cutting processes. The quality of the surfaces after thermal cutting processes were evaluated in accordance to ISO 9013:2017 (bevel angle, surface roughness, rectangularity tolerance). Also, measurements of cut widths and breakthrough holes diameters were accomplished. In the next stage the hardness measurements and metallography examination were performed. The following devices were used for this purpose: metallographic light stereoscopic microscope Olympus SZX9 and Wilson Wolpert 401 MVD for Vickers’s hardness measurements.
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