High chromium white cast iron or high manganese steel is usually used to cast wear-resistant parts such as grinding roller, grinding disc and plate hammer used in thermal power generation, mining and cement industries. Due to the wear of coal mine and sand, the working environment is bad, which will cause a lot of energy and material consumption every year. Single performance materials can not meet the requirements of working conditions, and ceramic particle reinforced metal matrix composites have both metal toughness and ceramic high hardness and wear resistance, which has gradually become a research hotspot. Powder metallurgy was used to prepare ceramic / metal matrix composites in the early stage. Fan ruiruirui et al. Prepared Al2O3 particle reinforced Fe Matrix Composites by powder sintering method. The research shows that adding C element can improve the hardness of quenched ceramic / metal matrix composites to HV 900, and the wear resistance is good. At present, the porous ceramic matrix was prepared by casting ceramic particles with a certain proportion, and then the ceramic matrix composites were prepared by casting ceramic particles with a certain proportion. Zheng kaihong et al. Made WC particles into honeycomb core plate, then cast and infiltrated high chromium cast iron (HCCI) liquid to prepare composite materials. WC was metallurgical bonded with HCCI matrix through dissolution and diffusion.
Compared with Al2O3, ZrO2 toughened alumina (ZTA) ceramics are toughened by tetragonal ZrO2 stress-induced phase transformation and microcrack toughening, which can be used as the reinforcing phase of metal materials. Qiu Bo et al. Manufactured ZTA particle reinforced HCCI matrix composites by fast flow mixing and high pressure compounding (fm-pc). When the impact energy changes from 1.5 J to 4.5 J, the relative wear resistance is 2.35-1.74 times of that of HCCI. In actual production, magotteaux company of Belgium has developed xwin technology to cast ztap grid composite on the surface of grinding roller and lining plate, and the wear life is 1.5 ~ 2 times longer than that of traditional wear-resistant materials. At present, it is difficult to solve the problem of wettability between metal and ceramic by cast infiltration method, which is of great risk for manufacturing large castings. However, the cost will increase sharply if the powder sintering method is used as a whole. In this paper, a preparation process of ztap reinforced HCCI matrix composite by powder sintering and casting was explored, and the composite was used to prepare large castings such as grinding roller and liner.
HCCI was used as matrix and ztap as reinforcing phase. Firstly, ceramic particles, high chromium alloy powder and binder were mixed and sintered to prepare honeycomb cermet preform by vacuum sintering method. Then, high chromium molten metal was poured to prepare ztap reinforced HCCI composite. Then the interface microstructure of ZTA ceramic and HCCI was studied, and the wear resistance of cermet composite was evaluated by three body abrasive wear test.
(1) ZrO2 toughened alumina ceramic particles (ztap) distribute uniformly on the high chromium cast iron (HCCI) matrix without agglomeration and dispersion.
(2) The sintered HCCI matrix is remelted in theand metallurgical bonding with the cast HCCI matrix is formed. The bonding properties of sintered HCCI matrix and ztap are good, and there are no defects such as cracks and pores in the interface.
(3) The three body wear test shows that the volume loss of ztap reinforced HCCI matrix composites decreases gradually and tends to be stable with the increase of grinding range, and the wear resistance of three body composites is more than three times that of HCCI.
(4) The ztap / HCCI composite roller has been successfully prepared. After 5000 hours of service, the wear loss of the cylindrical zone and the composite zone in the roller radius direction are 8.2mm and 5.9mm respectively, and the service life is expected to be more than twice that of HCCI roller.