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Steel bearings have plenty of usages in manufacturing different kinds of ball bearings, bearings and cold rolling rollers. Heat treatment has an important role in the properties of this group of steels. Therefore, in current research the effect of tempering temperature on the microstructure, hardness, impact energy and wear resistance in forged steel containing Chrome, Manganese and Molybdenum will be studied. For this purpose, the samples were tempered after austenitizing at 900°C and quenching in the oil at 6 temperatures of 150, 250, 350, 450, 550 and 650 °C for an hour. Then microstructural studies and mechanical properties of the samples including hardness, impact energy and wear resistance were surveyed on the samples. The results showed that the hardness was gradually decreased (impact energy gradually increased) at the temperature range of 150 - 250 °C and at temperature range of 350 - 650°C, the hardness would decrease and the impact energy would increase. Also, the wear resistance would decrease with an increase in the tempering temperature. The result should be justified considering the softening of the structure and the reduction in martensite tetragonality which stems from an increase in the tempering temperature. The study of the wear surface of the samples indicated that the dominant wear mechanism was adhesive wear in which with an increase the tempering temperature due to a reduction in the hardness of the samples, more sever adhesive wear was observed. [ABSTRACT FROM AUTHOR]

The present study describes the influence of the welding speed on the microstructure and mechanical properties of 5086 aluminum alloy joints fabricated by friction stir welding. The joints were welded at a constant rotation speed of 100 rpm and different welding speeds ranging from 63 to 100 mm/min. The experimental results revealed that the nugget size decreases with increasing the welding speed. Although all of the identified particles in the parent alloy appeared in the WNZ and HAZ areas at the welding speed of 63 mm/min, the number and size of the particles of each type present at these areas were different. Additionally, at higher welding speeds of 80 and 100 mm/min, the particles conditions were different as opposed to the welding speed of 63 mm/min. The hardness profile of weldments was roughly homogeneous with minimal fluctuations with increasing the welding speed. The tensile strength increased with increasing the welding speed from 63 to 100 mm/min. The joint ductility showed a behavior similar to the tensile strength. [ABSTRACT FROM AUTHOR]

Alternative to current liquid amine technologies for post-combustion CO 2 capture, new technologies such as adsorbent-based processes are developed, wherein material lifetime and degradation is important. Herein a robust method to determine degradation rates in a laboratory setup is developed, which was validated with a continuous multi-staged fluidized bed pilot plant designed to capture 1 ton CO 2 per day. An amine functionalized polystyrene adsorbent showed very good agreement between the experimental 1000-hour laboratory degradation rates and 2200 hours of degradation in a pilot plant. This validates how laboratory experiments can be extrapolated for sorbent screening and for scale-up. Resulting, the oxidative degradation in the desorber at high temperatures (120 °C) and low O 2 concentrations (150 ppmv) is 3 times higher compared to the adsorber at low temperatures and high O 2 (56 °C, 7 vol %). Laboratory degradation experiments can hence be used to further optimize process operations to limit degradation or screen for potential new adsorbents., (© 2023 Shell Global Solutions International B.V. ChemSusChem published by Wiley-VCH GmbH.)