抄録
The overall objective of this project was to provide a date showing how carbide powder in addition to metal powder can be used effectively to increase the hardness of overlay composite alloy and hence increase resistance to abrasive wear.
An experimental study was performed to examine of combination of metal powders and reinforcing powders. The metal powders considered were stainless steel powder, Ni-base alloy powder, Cobase alloy powder and high speed steel powder, and reinforcing powders considered were metal-carbide powders and ceramic powders. Carbide and ceramic dispersion type overlay composite alloys were produced by plasma transfer arc powder welding.
The overlay composite alloys were consisted of matrix and carbide powder fused with base alloy metal and forming eutectic structure, and non-fused carbide particles which are the partially melted reinforcing powder. The average hardness of matrix depended on the kind of base metal powder and the existence of reinforcing powder. The average hardness of matrix for high speed steel powder was higher than other powders used, but the hardness of other powders used, increased with addition of reinforcing powder compered to each base alloy metal only without addition according to fused the powder.
To assess the resistance to abrasive wear of overlay composite alloy a rubber wheel abrasion test was performed on its surface. Weight loss of overlay composite alloy by wear was decreased more with addition of reinforcing powder than base alloy metal only without addition of its powder due to the existence of non-fused carbide particles in it. Especially, the abrasive wear resistance of composite alloys depended on the increase in the volume fraction of non-fused carbide particles.
The addition of carbide powder, especially Ti-carbide, to base metal powder can be used effectively to increase the hardness of overlay composite, and hence increase resistance to abrasive wear of it.
