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

Abstract

The microstructures of B bearing cast steel (B steel) containing 0·8–1·2 wt-%B, 0·8–1·2 wt-%Cr, 1·0–1·5 wt-%Mn, 0·6–1·0 wt-%Si and 0·10–0·25 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−2respectively. 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.