Study On Laser Cladding Layer Of Iron Based Alloy Reinforced By Ceramic Particle

In the fields of metallurgy, mining, construction, road construction, petrochemical, and coal production, iron and steel material is still mainly used as structural materials, but the work environment makes the device prone to wear and failure. Every year,1/3-1/2of the energy is consumed in the different forms of friction and wear, the loss is up to＄100billion due to wear failure in The United States. And the annual loss is up to hundreds of billions in China. Therefore, to improve the wear resistance of the material has been the imminent problems of the production unit and the mission of scientific workers.Composite ceramics particles enhanced cladding layer was prepared by laser cladding in-situ synthesized on the surface of low carbon steel. Cladding layer has good abrasion resistance. Microhardness tester, optical microscope, scanning electron microscopy (SEM), X-ray diffraction (XRD), and sliding wear testing machine are used to test and analyze the micro structure and properties of laser cladding.Means of in-sync is used to research the influence of laser scanning speed, laser power, multi-channel overlap rate, shielding gas flow, carrier gas flow rate, and the powder feed rate on the forming and performance of the cladding layer. Research shows that, a large area cladding layer with good forming can be obtained under2000W laser power,250mm/s scan velocity, shielding gas flow rate of6-7L/min, powder feeding rate for10g/min and overlap rate of30%.The impact of organization and the performance of the different components of the alloy powder are researched. Ferro-titanium, molybdenum, boron carbide generate a large number of carbide particles by in-situ reaction in the cladding layer. These carbide particles play the role of particle reinforced. However, when these components surpass a certain amount, it is difficult to form a good cladding layer because of melt viscosity increasing, and cracks in the laser cladding maybe appear. TiB2, TiC and MoC may be generated by the reaction of ferro-titanium and boron carbide. Ferrotitanium and ferromolybdenum effectively enhance the wear resistance of the layer. A small amount of carbide generate by Ni, Cr, Mo and C in high-nickel-iron based powder.Through cladding alloy powders consisted of Ferrotitanium (Wt(Ti):30%), ferromolybdenum (Wt(Ti):60%), B4C, High-nickel-iron based powder mixed powder, wear-resistant coating was claded on low carbon steel substrate. Prepared TiB2, TiC, and MoC and B4C composite particles reinforce iron-based cladding layer. The laser cladding layer has good surface forming, and there were no slag inclusions, cracks and other defects inside. Organized and the hard phase are refine and uniform dispersion. The wear mechanism of the composite phase cladding layer is the micro-cutting and adhesive wear. As cladding layer has a higher average microhardness (about1100HV0.3), cladding layer is difficult to plastic deformation in the wear process, which showed excellent wear resistance. Under the same experimental conditions, the wear weight loss of composite layers is about1/25of the substrate. That the wear resistance of the cladding layer is about25times that of the Q235.