Study Of High Velocity Oxygen Fuel Spraying Coating Characteristics Of Boiler Tube

As a kind of important and mature surface treatment technology,thermal spraying is widely used in metal corrosion and repair.High Velocity Oxygen Feul?HVOF?spraying coating has became the main direction of the thermal spraying because of the corrosion and abrasive resistant recent years.Domestic new spraying coatings have been developed,and obtain good economic benefit,but the lack of sufficient test data as the basis,to compare the pros and cons of coating;for boiler heating surface coating of ash deposition and slagging phenomenon at the same time,the lack of experimental comparison and explored.So there are lack basis to provide reference for the preparation of new coating material.In this work,HVOF technology was used.Compare to the alloy 12CrMoVG which is in common use of high temperature superheater,spray three different alloy powder—NiCr-Cr₃C₂?NiCr-3?Ni60A,oxidation?corrosion and ash deposition experiments was processed on 600and above temperature condition.To compare the advantages and disadvantages of three coating and analyse the reason that cause the different performance.According to the data of the experiments,we got the kinetic curves of high temperature oxidation and thermal corrosion of the test specimens,through ESEM technic to analyset the morphology features of the surface.It turned out that,Cr₃C₂?Cr₇C₃ and Cr₂O₃ are the main protective screen to protect the materials from high temperature corrosion..So the NiCr-Cr₃C₂coating show the great performance of corrosion and abrasive resistant.As for the stomatal of NiCr-3 and lack of Cr element,this two kind of HVOF coatings'property are not as well as the NiCr-Cr₃C₂ coating.Under the condition of different temperature,use the slagging characteristic of the high contaminates coal,compare ash deposition and slagging phenomenon on the different specimens.The result show that,undre the low temperature,there are ash deposition on the surface of the alloy,and the surface of NiCr-3 coating got slightest ash because of the smooth finish.Under the high temperature,the NiCr-Cr₃C₂ coating show greatest property of control the slagging problem.In this work,we find out the HVOF spraying coating obtain a great effect of improve the corrosion and abrasive resistant of the boiler tube.And the NiCr-Cr₃C₂ coating show the best property among this three different coatings,at the same time,it also could make a good effect on controlling the slagging phenomenon of the high contaminates coal using in power plant.