Investigations on microstructures and properties of B containing cast steel for wear resistance applications

The microstructures of B bearing cast steel ( B steel) containing 0 center dot 8 - 1 center dot 2 wt-% B, 0 center dot 8 - 1 center dot 2 wt-% Cr,1 center dot 0 - 1 center dot 5 wt-% Mn, 0 center dot 6 - 1 center dot 0 wt-% Si and 0 center dot 10 - 0 center dot 25 wt-% C have been characterised by means of optical microscopy, scanning electron microscopy, electron probe microanalyser and X- ray diffraction. The solidification structure of B steel consists of pearlite, ferrite, martensite and boride (Fe2B), while the hardness is 1430 - 1480 HV. Borides distribute along the grain boundary in the form of eutectic. Fine lath martensite and eutectic Fe2B can be obtained by water quenching at 1223-1273 K. The hardness and impact toughness of the B steel exceed 55 HRC and 150 kJ m(-2) respectively. The abrasion resistance determined using a pin abrasion tester is obviously higher than that of the martensitic cast steel and nears to the high chromium white cast iron.