Peculiarities of Structural Transformations at High-Speed Steel Heating

The aim of the paper is to discuss about the structural transformations at high-speed steel heating. Under the conditions of high-speed heating steel of posteutectoid composition realized by laser application and electron accelerator ledeburite formation that is the structure characteristic for pig iron has metallographically been revealed. Ledeburite formation in steels is conditioned by quick achievement of eutectic reaction temperature and keeping cementite areas in local fields at this temperature. It has been shown experimentally that ledeburite formation occurs at heating at the rate about 2500 degC/s in steel with windmannstet cementite structure.Using the method of mathematical simulation it has been shown that ledeburite structure theoretically cannot be obtained at heating steel with plate perlite structure thickness of which is 1-2 orders less than thickness of windmannstet cementite plates.