Steel, non-metallic inclusions, laser action, strengthening, gradiental and composite zones

Purpose. It is interest to research the behavior of non-metallic inclusions under laser treatment of steels. It is necessary to analyse the peculiarities of influence of speed melting and crystallization of inclusions on the local strengthening of steel matrix. Also it is necessary to discover the possibilities of controlling heterogenezation of steels structure in the time of formation of local gradiental and composite zones of contact interaction in systems inclusion-matrix. The goal of work is elucidation of principal generalities of transformation of interphase inclusion-matrix boundaries and formation of zones of contact interaction under laser treatment of steels. Methodology. The materials for investigation were commercial steels containing different non-metallic inclusions. The specimens of different steels with preliminary polished surface were exposed to laser beaming on the installations GOS-30M and GUANTUM-16 using different energy of impulse. Findings. It was fixed under laser strengthening of steels containing non-metallic inclusions takes place combination laser heat treatment with micro-alloying of local section of matrix from inner sources - non-metallic inclusions. The level of strengthening of inclusion-matrix boundary is defined by optimal relationship of speeds of dissipation and activization processes. Investigation o f peculiarities of formation o f contact interaction zones in steel matrix and inclusions and also of the strengthening of inclusion-matrix boundaries was allowed to determine the series of principles of their transformation under laser action and their influence on the local strengthening of steel matrix. Originality. The peculiarities of structure of gradiental and composite micro-zones arising in the moment of laser action were determined. Practical value. The using of receiving results will allow to elaborate the regimes of laser treatment allowing to use the non-metallic inclusions as inner sources of micro-alloying that will allow to directly influence on the level of strengthening of steel under laser treatment.