球形铸造碳化钨对PDC钻头喷焊层冲蚀性能的影响

Influence of Spherica Cast Tungsten Carbide on Erosion Resistance of Spray Welding Coating of PDC Drill Bit

本研究采用氧乙炔喷焊方法制备了不同含量的球形碳化钨和多角状碳化钨颗粒增强的镍基喷焊涂层,研究了钢体PDC钻头碳化钨喷焊层的抗冲蚀性能。结果表明:随着球形碳化钨含量的降低,喷焊层的显微硬度降低,断裂韧性增加,孔隙率先增大后趋于稳定;喷焊涂层的抗冲蚀性随球形碳化钨含量的降低呈先降低后升高的趋势,耐腐蚀性是影响喷焊涂层抗冲蚀性最主要的因素。当球形碳化钨含量为30%时,样品抗泥浆腐蚀性能最差,腐蚀—冲蚀互作用最强,导致样品受冲蚀磨损最严重。建议球形碳化钨含量不低于40%,可以保持喷焊层较高的硬度和抗冲蚀性能。

In this work,Ni-based spray welding coatings reinforced with various content of spherical cast tungsten carbide(CTC-S)and angular cast tungsten carbide(CTC-A)particles are fabricated with the oxy-acetylene welding.The erosion behavior of WC-Ni hardfacing used for steel body PDC drill bit are investigated inexperiments.Results show that as CTC-S content decreases,the microhardness of coatings decrease while their fracture toughness increase,and the porosity increases firstly and becomes stable.The erosion resistance decreases firstly and increases with the decreasing of CTC-S content,and the corrosion resistance is the most important factor affecting the erosion resistance of the hardfacing coating.When the content of CTC-S is 30%,the corrosion resistance of the sample is the worst,and the corrosion-erosion interaction is the strongest,leading to serious erosion wear of the sample.It is recommended that the content of CTC-S should not be less than 40%to maintain the high hardness and erosion resistance of the coating.