The microstructure and mechanical properties of laser cladding nanometer tungsten carbide coating:
In tungsten wire carbide, tungsten carbon atoms embedded metal lattice clearance, does not destroy original metal lattice, interstitial solid solution formation, therefore also calls the caulking compounds (or insert). Tungsten carbide can be made of a mixture of tungsten and carbon heating system, the existence of hydrogen and hydrocarbons can accelerate the reaction. If use tungsten preparation of oxygen-containing compounds, vacuum processing products must eventually in 1500 ℃, to remove carbon oxides. Tungsten carbide is suitable for machining under the high temperature, can produce cutting tools, structure materials of kiln, jet engines, gas turbines, nozzle, etc.
Another of tungsten eletrode and carbon compounds as the two tungsten carbide, chemical formula for the W2C, melting point is 2860 ℃, boiling point 6000 ℃, relative density 17.15. Its properties, preparation, use with tungsten carbide.
Using 7 kw crosscurrent CO2 laser in the laser cladding was carried out on 2 crl3 stainless steel substrates of nanometer WC powder experiment. Using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray energy dispersive spectrometer (EDAX), microhardness tester and equipment inspection organization and performance of the coating. The results show that the laser cladding method of nanometer WC powder can be dense composite coating; Coating and cladding zone presents a typical Fe cellular dendrites and branches of intergranular Fe - C - W group; XRD analysis showed that the composite coating is mainly composed of Fe, WC, W2C and Fe3C several phase composition; Coating performance test results show that the surface hardness is 1750 hv. The cladding layers average hardness is 1200 hv, wear resistance is 2.5 times higher than the matrix.
Valve is dosage of mechanical industry in big and one of the main basic parts. The valve in the process of frequent opening and closing, the sealing surface is scratch, plus medium corrosion, erosion, and the role of the high temperature and other factors, and make the valve sealing surface damage early, become the untight seal, source of leaks.