Effect of thermomechanical treatment on sliding wear of high-Cr cast iron with large plastic deformation
The effect of thermomechanical treatment on sliding wear of high-Cr cast iron was studied. Due to the inherent embrittlement of high-Cr cast iron, the bimetallic composites, in which the cast iron was cladded by low carbon steel, were prepared to conduct plastic deformation in the temperature range of 950-1150 °C with the strain rate of 0.001 s-1. The wear properties of the as-cast high-Cr cast iron and the bimetallic composites were compared using pin-on-disc type sliding wear tests. Experimental results demonstrated that the brittle cast iron was severely deformed with crack free at high temperatures in the form of bimetallic composites. The thermomechanical treatments not only rotated the carbide orientation with ∼90, but also increased the volume fraction of carbide. Because the long axes of carbide rods were parallel to the worn surface and the higher volume fraction of carbide provided a better protection for the ferrous matrices, the bimetallic composites bonding at 1050 and 1150 °C had a better wear resistance than the as-cast high-Cr cast iron. However, the wear resistance of the bimetallic composite bonding at 950 °C was inferior to the as-cast high-Cr cast iron due to the higher volume fraction of carbide void accelerating the wear rate on both carbide and ferrous matrix.