Study On Non-slag Wear Resistance Surfacing Electrode With Lron Powder And Welding Process

At the present time, the main alkalinous hardfacing electrode that were produced and applied are Fe-C-Cr, Fe-C-B, Cobalt-based and Nickel-based system alloys which contain low hydrogen. But they are not smooth to start arc, there are much slag to clean up after welding, and the Co and Ni's price are very high, meanwhile they are also our country's rare resources. To solve the problem above, this paper develops a new style Fe-C-Cr-W-Si-B system hardfacing electrode whose hard phase are carbides, borides or nitrides. The new hardfacing electrode could start arc smoothly, and with no slag covered the weld, its price is low and deposition efficiency is high. There are much graphite in the coat to stead griotte and some other gas-forming agent in traditional coat to protect the weld metal and improve the electrode's extrusion property. Adding some components contained B, Si to improve appearance of weld by deoxidating itself, reducing the melting point of deposition metal and increasing the molten's flowing power. Otherwise, large quantity iron powder was put in the coat. One side, it could improve the electrode's start and restart property. The other side, it increases the efficiency of the electrode.The electrode was made by TL-25 electrode forming machine. The result of procedure qualification test showed that the deposition efficiency is 225% which is 105% higher than high manganese surfacing electrode, and the welding current and speed influence the hardnessl and abradability of deposited metal. The influence of Cr, Mo, V and C on the hardessl was studied. The result showed that the hardness value is largest up to 66HRC when the graphite is 6% of the coat in weight. Evaluating the deposited metal's crack resistance by point weld on the weld. Adopting optical microscope, SEM, X-Ray diffraction instrument and electron spectrometer to analyse and attribute the Fe-C-Cr-W-Si-B alloy's microscopic structure and composition of metallic phase. The test result showed that the alloy's matrix are ferrolites, martensites or austenites, and the hard phase contains Fe3(B,C),Si5C3,B4C,WC,Fe4N,Fe2N.The damp sand grain-abrasion test showed that the Fe-C-Cr-W-Si-B alloy's wear-resisting property is good which is high than high-chromium cast-iron hardfacing electrode.The electrode that was created could repair the wearing coat of roll breading machine, the blade of shearing machine, the tooth of digging machine and mixing plate of mud-hog pump. It could also be used in manufacturing the new parts of these machine.