Microstructures and mechanical properties of sprayformed white irons

摘要

This paper presents a preliminary research in which sprayforming process is used to modify the eutectic carbide morphology and properties of white irons. The sprayformed white irons are compared with those of traditional cast samples. As a rapid solidification process, sprayforming dramatically reduces carbide size and modifies the carbide morphology. Isolated eutectic carbides can be achieved with a low chromium iron. With adequate alloying of chromium, vanadium and molybdenum, the carbides are formed as fine and evenly distributed nodules in the order of microns. Segregation problems normally encountered in high vanadium alloy casting are eliminated. Sprayformed iron may offer excellent combination of hardness and toughness for high wear performance with heavy impact loading. Machinability of the iron is also improved. The sprayformed irons may be suitable to make such wear resistant components of near net shape as compound tubes and clad rolls. The potential of sprayformed white irons in these applications and the factors affecting the bonding of the cladding layer to the substrate as well as their influence on the microstructures are discussed.