Effect of Heat Treatment on the Microstructures and Properties of Modified High Boron Cast Steel
The effect of quenching temperature on the microstructures and properties of high boron cast steel modified with rare earth and titanium has been investigated.The results show that the solidification structures of cast steel consists of high hardness boride,ferrite,pearlite and a small quantity of martenisite that is fabricated by adding a suitable boron element in the low carbon steel and modification with rare earth and titanium.The metallic matrix of modified high boron cast steel changes into the single martensite from the composite structures of ferrite,pearlite and martenisite along with the increase of quenching temperature.The increase in quenching temperature also leads to the transformation of boride from continuous shape to isolated shape and promotes the coarsening of boride.Moreover,when quenching temperature is increased,the hardness and impact toughness of high boron cast steel are increased also.The hardness and impact toughness have no obvious change while exceeding 1 000 ℃.High boron cast steel quenching at 1 000 ℃ consists of single martensite and isolated boride and has excellent wear resistance.