Impact abrasive wear behavior of thixo-injecting forming hypereutectic high Cr cast iron billets by conventional sand casting and by slope cooling semi-solid casting was analyzed. The results show that slurry fluidity is greatly decreased due to coarse rod-like carbides in conventional as-cast billets

which results in surface rough and internal shrinkage hole in thixo-injecting forming parts

meanwhile

matrix is obviously fragmented by coarse rod-like primary carbides

and the carbides are broken off during wear process

leading to the deterioration of wear resistance. Slurry exhibits acceptable fluidity during thixo-injecting forming process as a result of fine primary carbides in slope cooling semi-solid billets

which leads to smooth surface and low internal defects in the parts

meanwhile

primary carbides and eutectic carbides show fine and uniform

resulting in the low cutting role in matrix and uniformly surface wear

which are responsible for the improvement of wear resistance.