Features of structure influence on the mechanism of steel destruction at repeated dynamic load under compression scheme

The model of growth of a fatigue crack in conditions of dynamic compression has been developed. Features of fatigue cracks nucleation and development in steels with various structure have been revealed. It has been found out that preferable directions of crack development are the grain borders or boundary surface between structural components. Nonmetallic inclusions are places of primary microcrack nucleation. It has been revealed that under dynamic compression the process of secondary microcracks formation is developed intensively. Chipping of significant volumes of material at the place of the main crack has been observed thus intensifying the wedging effect and accelerating the destruction process.