Development Of New Wear Resistant And Heat Resistant Electrode For Surfacing

At present, materials used in wear resistance and heat resistance in the world are mostly cobalt base stellite and wear resistant materials of nickel base surfacing alloys, which are too expensive to apply widely though they have some outstanding merits in the aspects of wear resistance, and thermal stability and so on. To solve the problem above, in this paper, we have developed one kind of Fe-C-Ti-Mo-W-V- B system particles reinforcement iron base wear resistant and heat resistant electrode for surfacing by the method of orthogonal experimental design, using H08A core wire, adding graphite, ferrotitanium, ferrovanadium, ferromolybdenum, ferrotungsten and B4C, etc, choosing appropriate slag system. The microstructure and performance of the surfacing layers were studied by the optical microscope, the X-ray diffraction, the Rockwell durometer and the microhardness instrument. The function of the elements in the hard-facing alloy including C, Ti, W, Mo, V, B, etc, and the effects of these alloy elements on the hardness and on the microstructure are also analyzed in this paper. At the meantime, the effect of the amount of graphite and ferrotitanium in the fluxes on the hardness and microstructure were studied. At last, the wear mechanics of surfacing layers were researched. The results of assays study were as follows:(1) The electrode for surfacing had good processing property such as good arc stability, good slag detachability, nice weld metal and so on. The macrohardness of the surfacing alloy was more than 63HRC, and had good crack resistance and good wear resistance.(2) The effect of the amount of graphite and in the fluxes on the hardness was very apparent. With the amount of graphite increasing, the hardness of the surfacing layer was enlarging. However, while the amount of graphite was more than a definite amount, the increment of hardness was not apparent, even falling down. With the amount of ferrotitanium increasing, the hardness of surfacing layer was increasing at first and then falling down.(3) After observing the microscopic structure, the matrix was made up of carbon martensite, retained austenite and disperse particles. After analyzing by XRD, the particles were TiC, VC, WC, B4C, Mo2C and TiB2, etc. As a result, polyphase composite reinforcement particles were successfully generated by original position through chemical metallurgy reaction. The new surfacing alloy had excellent wear resistance and heat resistance.(4) The surfacing layer was heating for 6 hours at 750℃, and cooling to room-temperature in the heater. The hardness of surfacing layer was 49.57HRC, indicating excellent high temperature resistance and wear resistance.(5) The new wear resistant and heat resistant surfacing electrode had the features of low cost, excellent processing property and better wear resistance and heat resistance, which had good engineering application value.