Study On Ni-based Alloy Coating Prepared By High Frequency Induction Cladding

With the ongoing of the exploration of oil,the work environment of the sucker rod bcomes more and more mal.The sucker rod failure accidents frequently occure,which have seriously affected the development of the oil field development project in a low cost and efficient way,as it is significant to improve the work efficiency of the sucker rod.In the working environment,corrosion and wear are the main problems faced by sucker rod.Therefore,in this article,in order to improve the corrosion resistance and wear resistance of the sucker rod,the Ni based alloy coating was prepared on the surface of sucker rod steel 35CrMo by high-frequency inducion cladding technology.The preparation process of high-frequency induction Ni based alloy coating was researched in this article,selcting the approprate binder and the content of the binder at first.The Ni based alloy coating was individully prepared by TiC doping and Ti+B4C doping.The microstructure and property characteristics of the Ni based alloy coating were analysed with the different addition contents of the reinforcing phase.The microstructure and phase of the Ni based alloy coating were researched by means of optical microscope scanning(OM)and X-ray diffraction(XRD).The micro-morphology and elmental compositions of the Ni based alloy coating were ananlysed by scanning electron microscope(SEM)and energy dispersive spectroscopy(EDS).The rockwell hardness tester and microhardness tester were individually used to test the surface macrohardness and the cross section microhardness.The wear tester and electronchemical workstation were used to evaluate the wear resistance and the electrochemical properties of Ni based alloy coating,getting the following conclusion:(1)Compared with the polyvinyl alcohol and sodium carboxymethly cellulose,as the binder of Ni based alloy coating,using water glass could obtain the coating with better detachability and superior forming quality.When the content of water glass was about 8%,the coating combined closely with less porosity,cracks and other defects.The Ni based alloy coating prepared by high frequency induction cladding technology could gain good metallurgical bonding between the coating layer and substrate.(2)Ni based alloy coating was mainly composed by y-Ni,Ni3Fe,Ni3Si,CrB and Cr7C3.Compared with the 35CrMo substrate material,the properties of hardness,wear resistance and electrochemical of the Ni based coating were significantly improved.From the substrate to the surface of the coating,the microhardness gradiently increased.Adding with the different contents of wild phase material could effectively improve the hardness and wear resistance of the coating,but the electrochemical properties decreased slightly.The friction coefficient and the wear loss of the coating decreased with the increasing stress and the decreasing rotating speed.(3)When the TiC particles were added to the Ni based alloy coating,TiC could disturb the growth of the columnar crystals.Ordinarily,the TiC particles embedded in the eutectic microstructure which distributed along the grain boundary of the y-Ni.With the TiC contents increasing,the nunber of the defects increased in the coating,and the surface hardness and the wear resistance increased first and then decreased.When the addtion content of the TiC was about 10%,the coating had the better hardness and wear resistance.(4)There emerged TiC and TiB2 in the Ni based alloy coating with Ti+B4C doping,and the second phase distributed along the grain boundary uniformly.And with the addition content of the Ti+B4C increasing,the coating structure tended to be fine and uniform,and the hardness and wear resistance also increased.