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Incineration is currently the standard way of disposing of municipal waste. It uses components protected by high-temperature-resistant layers of materials, such as Inconel alloys. Therefore, the objective of the current paper is to study the mechanical properties and structure of a bimetallic Inconel 625-16Mo3 steel tube. The Inconel 625 layer was 3.5 mm thick and was applied to the surface of the tube with a wall thickness of 7 mm via the cold metal transfer method. The bimetallic tube was bent using a supercritical bend (d ≤ 0.7D). This paper is focused on the investigation of the material changes in the Inconel 625 layer areas influenced by the maximum tensile and compressive stresses after the bend. The change in layer thickness after the bend was evaluated and compared to the non-deformed tube. In addition, the local mechanical properties (nanohardness, Young modulus) across the indicated interfacial areas using quasistatic nanoindentation were investigated. Subsequently, a thorough microstructure observation was carried out in areas with maximum tensile and compressive stresses to determine changes in the morphology and size of dendrites related to the effect of tensile or compressive stresses induced by bending. It was found that the grain featured a stretched secondary dendrite axis in the area of tensile stress, but compressive stress imparted a prolongation of the primary dendrite axis. [ABSTRACT FROM AUTHOR]

The research carried out by the authors of this paper is focused on the technological process of Inconel 625 welding with the MAG–CMT (Metal Active Gas-Cold Metal Transfer) method. Inconel 625 was welded to the substrate material, which was 16Mo3 steel. Both materials are used to produce the so-called bimetallic tubes, which in practice serve as a part of the equipment intended for waste incineration. For this reason, the bimetallic tubes must withstand extreme conditions during their operation. Therefore, bimetal pipes are highly stressed composite components that must resist corrosion in a chemically aggressive environment. For this reason, an extensive material and technological analysis of the production of pipe bends with a supercritical bend of 0.7D from bimetal pipes with Inconel 625 cladding was performed. In the welding process, the authors investigated the possibilities of the CMT method with and without using the oscillating movement of the welding head. The most important factor in deciding which method would be appropriate was to measure the amount of iron on the surface of the coating layer. The authors' paper builds on the authors' previous research in this area, which was mainly focused on research on the critical bending of bimetallic tubes. [ABSTRACT FROM AUTHOR]