V-epc Preparation Of Iron-based Surface Wear-resistant Composite Material

With V-EPC casting-penetrating technologies, WC particles reinforced low chromium cast iron and HT300 steel matrix surface-layer composites were successfully gained in the thesis. The casting process was optimized, the composites obtained have a high dimension precision and good surface quality . The sound coating for EPC is composed of: 100 percent of quartz sand, 4 percent of Na-sulfuryl bentonite, 3 percent of Na2CO3 (of Na-sulfuryl bentonite), 2.5 percent of white-latex, 0.5 percent of CMC, 0.05 percent of twelve alkyl phenyl sulfonic Natrium, 0.02 percent of ortho octahydrin, and the binder is 6%PVA, NaF is except, the perfect position of pouring is at the bottom of casting. WC is even in composites. The binding between composites layer and matrix is excellent, which is matellurgical binding. Between the matrix and composites has an even interface area with the substrate, with good bonding strength. During the process of composite,it is mainly the osmosis of iron liquid ,and alloying element also osmosizes to matrix ,but the quantity is very little. The matrix structure of composition is WC, W2C, M7C3, M23C6, M6C, M12C carbide and Troostite.The paper study the influence regularity for the surface quality of composite on pouring temperature, extraction time, WC particle size, WC volume fraction, parietes thickness, base material , and so on. The dimension precision study indicate when the position of pouring is at the bottom of casting, the dimension precision is good, the grade is CT5 to CT8, when at the side face of casting, the dimension precision is average,and when at the top of casting , the dimension precision is difference. Atthe same time, the dimension precision increases with diminution of WC volume fraction. But from the massing, the effect on the dimension precision of composites using V-EPC for particle layer coated in casting surface is little , and the dimension precision remain with high level which can satisfy the need on precision for casting resisting abrasive wear and some castings of needing low precision even directly is used.The thesis designed successfully and produced a three-body abrasive wear tester, and conduct reproducibility experiment. The experiment resultindicate the tester exhibited good reproducibility. The wear experiment result indicate three-body abrasive wear performance is increased significantly , which increased upmost 7.65 times, compared with high chromium cast iron. And the abrasive wear performance of composites is increased with accretion of stress and WC volume fraction, abrasive wear mechanism is shield of WC to other organization, shade effect, and failure patter is flaky exfoliation of WC for fatigue.