| Recently, ceramic particles reinforced iron matrix composite arouse material researchers wide concern because it effectively combined well plasticity and toughness of iron-based materials, high hardness and wear resistance of ceramics. In this paper, we prepared flux-cored wire which use H08 A as scarfskin, ferromanganese,ferrosilicon, ferrochromium, and graphite as based alloy system. Wearing layer were prepared by manual arc welding on the surface of Q235. We systematically analyse the influence of alloying element and WC particle to the microstructure and property of surfacing layer.The phase, microstucture, feature of fusion zone were investigated by means of metalloscope, X-ray diffractometer, scanning electron microscope. The hardness of surfacing layer and fusion zone were measured by rockwell hardness tester, and the wear property of composite was tested by rock grinding machine.The result showed that the alloying elements dramatically affect microstructure and property of surfacing layer. The wear resistance of material was related to the microstructure, which not directly corresponding to the hardness,and the single-phase austenitic organization was not conductive to the wear resistance. The modified alloy system contained 25%ferromanganese, 5%ferrosilicon, 10%ferrochromium, and 1.6%graphite. The surfacing layer were made up of ferrite austenite, martensite, chain-likeferrite, and a large number of diffuse distribution carbides. The organization were well-distributed and present in regular dendrite. The layer and matrix were metallurgically bonded and got a well plasticity and toughness, with a surface hardness of 53.5HRC, fusion zone hardness of 47.6HRC, and the hardness of base metal raised to 35.5HRC from 28 HRC. The relative wearability came to 2.114 times than that of contrast sample. The improve of hardness was determined by the dispersion of carbides and martensite.The smaller WC particle size, the easier melted and dissolved at welding heat effect. When adding 10%WC, the melted WC significantly enhanced the hardness of matrix with the WC size of 1000 mesh, while the 60 mesh WC dissolved the least which showed shadow protection effect on matrix and improved wear-resisting performance. The hardness of layer increased with WC content rised. However, the hardness increased rarely when the content of WC over than 30%. Conversely, the fragility of layer came larger and easily formed crack, the supporting role forced on WC weakened. As a result, the harden grain broke away from base metal. Mixing different size of WC together could significantly improve the performance of layer. The result shower that, the layer got a overall performance incluing dense microstruture, uniform composition, and well metallurgical bond with a ratio of 6:3:1, for 60,500,1000 mesh of WC.The WC particle formed a whisker contact with abrasive particle under light load, and play a role of anti-wear under effective support of matrix. The rotate speed came to be a leading factor that affect friction coefficient when the load keep the same. The faster the rotation, the smaller the sliding friction, and the smaller the friction coefficient. Adding WC could obviously reduced the abrasion lossunder the circumstances of high load and speed. The layer showed imparity wearing performance in different wear medium. The wearing loss in 120 mesh sandpaper was lower than that in 240 mesh. The surface temperature rose sharply with the wear conduct proceeded, and the rised temperature of friction pair lead to the reduce of wear resistance. |
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