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EN
The work is devoted to studying the technological capabilities of the processes of microplasma spraying of wires from heat-resistant nickel alloy Inconel 82 with further laser melting of the sprayed layers to produce narrow-path coatings during restoration of worn end faces of ribbed parts, used in nuclear engineering, aerospace and textile industry, etc. Numerical modeling by finite element method was applied to select the parameters of the modes of microplasma wire spraying and further laser melting of sprayed layers of Inconel 82 alloy. This made it possible to select the parameters of the modes with an accuracy of up to 20% (current 30-40 A at voltage 40 V, deposition speed 100 mm/min; radiation power 3.0 kW, defocusing spot 3 mm, remelting speed 750 mm/min). The value of the parameter of coating growth rate during microplasma spraying of Inconel 82 alloy wire was determined (it was equal to 1 mm of coating height / 1 cm of narrow path length / 1 min of spraying process duration). The work shows for the first time that the useful area of the microplasma spraying spot is close to the defocused laser radiation spot, ensuring unique possibilities for deposition of narrow paths and their laser remelting without hard phase burnout. This is experimentally confirmed by ~17% (290-350 HV) increase in the hardness of sprayed Inconel 82 layer (200-240 HV) during its remelting by radiation with power density of ~4.3·104 W/cm2. It was also determined that the features of structure formation during laser remelting of Inconel 82 alloy promote an enhancement of its corrosion resistance up to 1.5 times and increase in wear resistance by 20-40%, compared to sprayed coatings.
EN
This paper establishes the trends in structure formation of 4 mm thick 1561 aluminum alloy welded joints, depending on changes in the parameters of the MIG welding mode on a steel substrate (specifically, the speed and heat input of the process). Welding modes were selected based on the criterion of satisfactory seam formation, and the optimal welding mode was determined based on the criteria of minimizing porosity, grain refinement, and improved mechanical properties. Technological studies have shown that, based on the criterion of satisfactory seam formation with a quality level ranging from C to B according to ISO 10042, it is advisable to select a welding speed between 380 and 600 mm/min with a heat input between 217 and 240 J/mm. Metallographic studies have shown that increasing the MIG welding speed promotes weld grain refinement, decreases their shape factor, and simultaneously increases the number of pores while reducing their size. Mechanical tests demonstrated that increasing the welding speed enhances the mechanical properties of welded joints. Therefore, when using MIG welding of aluminum alloys in industry, it is recommended to increase the speed to 600 mm/min and higher.
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