High Wear-resistant Iron-based Overlaying Welding Electrode And Its Organization And Properties Of The Hardfacing Layer

For high wear-resistant overlaying welding materials, Cobalt base Stellite alloyand nickel base materials are the most common on the market at home and abroad,they have excellent wear resistance and high temperature stability, but they are tooexpensive to apply widely. So it is particularly important to develop iron-basedmaterials. In this paper, one kind of iron base electrode of resistance to hightemperature is studied, which uses the H08A core wire, adds the right amount of highcarbon ferrochrome, graphite, tungsten carbide, vanadium iron, titanium, iron,molybdenum iron, ferrosilicon, marble, fluorite and marble, ect. The microstructureand properties of surfacing layer are analyzed by OM, SEM, XRD, Rockwellhardness tester, and micro hardness tester. It is mainly focused on the effect ofgraphite, silicon iron, molybdenum iron and surfacing layer.The experimental resultsshow that:(1) Graphite content increases will lead to welding smoke and dust, and weldingslag off difficulties; when it is more than6%, the more graphite, the more eutecticorganization and particle phase, the better hardness and wear resistance, more than6%, organizations of graphitization, hardness and wear-resisting performancedegradation.(2) Ferrosilicon can improve the liquidity and reduce porosity in weld metalwhen it’s content within12%. But there will be stomatal due to excessive SiO2blocked airway after that;The increase of silicon content can promote solid solutionand precipitation of carbide alloy element, also can let the organization refinement,homogenization and the microstructure appears solid solution strengthening,fine-grain strengthening and dispersion strengthening three kinds of strengtheningmechanism;When the condition no more than10%, the proper increase of siliconcontent can improve the hardness and wear resistance of the overlaying welding.(3) Increase in molybdenum iron content can be alloy eutectic organization andthe number of carbide particles reinforced phase, increased to18%when the contentof molybdenum iron, diffuse distribution of carbide particles gradually gatheredtogether to form massive; The hardness of surfacing layer with increase with theincrease of the molybdenum iron, more than16%after the rise of small hardness, andwelding layer difficulty in deslagging, crack resistance variation; Molybdenum iron after more than12%, the wear resistance of surfacing layer with the increase ofmolybdenum began to decline.(4) With the increase of surfacing welding layer, the parent metal of surfacingwelding layer of diluting the weaker, the crystallization process of surfacing weldinglayer organization completed more thoroughly, and the dispersion strengthening phase,the more the hardness of surfacing layer is higher and higher. Layers of multi-passwelding time to control the temperature of the interlayer, is too low, weakens theeffect of preheating before welding, too much can cause large amount of heat input,cause burning alloy elements. Adjust the suitable welding procedure parameter is animportant premise to ensure the performance of surfacing welding alloy.