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This paper researches some problems with fatigue strength of bolted joints arising when used in metal structures subjected to cyclical variable loads associated with changes of pressure, temperature, wind characteristics, etc. Mechanical tests have been conducted on tension and hardness, macro-, micro-structural and fractographic analysis of steel bolts. Causes of destruction have been analyzed, some recommendations have been suggested to constructors of metal structures, manufacturers and users of bolted joints. [ABSTRACT FROM AUTHOR]

Improving the performance of components operating under heat stress and reducing the friction coefficient are critical factors in extending the lifespan of transport machinery as a whole. Accordingly, the objective of the present scientific experiment is to build upon previous research regarding the impact of a technological process of low-temperature gas nitriding (LTGN) on the microstructure and properties of aluminium alloy. The brand AlSi10Mg was used in this work and the change in its wear resistance was determined through experimental tests employing surface diffusion treatment method. The sample materials are widely used for the manufacture of pistons for the automotive and railway transport, as well as casting and machine components including connecting rods for agricultural machinery engines. [ABSTRACT FROM AUTHOR]

Aluminum alloys play a crucial role in transport industry, especially in the manufacturing of automobile and aircraft components, as well as various constructive parts. These materials possess exceptional corrosion resistance, excellent thermal conductivity and the ability to significantly reduce the overall weight of the transport vehicles, thereby minimizing the relative consumption of fuel. However, their mechanical properties fall short when compared to steel, prompting scientists to develop different surface technologies in order to enhance hardness and wear resistance. Thermo – chemical surface treatment is a conventional diffusion method employed for this purpose over the years. Investigated in the paper is the potential of low-temperature gas nitro-carburizing to enhance the hardness of samples of widely used aluminum alloy AlSi10Mg (Fe). Metallography and Xray analyses are presented, allowing close examination of variation in microhardness across the surface, through the diffusion zone and the core material. The results obtained pave the way for further investigations and research in the field of surface technologies for aluminium alloys. [ABSTRACT FROM AUTHOR]