Regarding some problems with bolted joints

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.