| The overflow parts(runner,top cover,bottom ring and guide blade)of a hydro turbine in a hydro power station are made of 0Cr13Ni5 Mo domestic super stainless steel,which is scoured by water and sediment during service,and the flow path,leakage ring and blade are worn out.For overcurrent wear,the method of surfacing is used to repair,but cracks often occur during repair.How to get a good deposited metal layer is an urgent problem.In this paper,a series of studies are carried out on the common form of 0Cr13Ni5 Mo stainless steel joint,which is welding,plate surfacing and angle surfacing.Two kinds of welding rods,three kinds of wire energy and four kinds of preheating temperature are used to weld.The fusion ratio,mechanical performance test and metallographic test of the obtained joints are carried out.The causes of cracks and the way to prevent cracks are analyzed.The analysis of adjacent welding tracks in multi-channel welding is carried out to find out the structure of each welding path,to analyze the performance of the transition zone,and to study the effect of thermal efficiency on the microstructure and properties of the various welds and transition zones.Finally,all the joints obtained under various technological conditions are in accordance with the requirements of GB/T 50766-2012 "installation and acceptance criteria for the production of water and hydropower projects".Considering all the parameters,the better welding parameters are: the baking temperature of the electrode is 300℃,the baking time is1.5h,the welding part is preheated 100~250℃,the welding line energy is controlled in10~15KJ/cm,and the heat preservation furnace is kept under the condition of 300℃ under the condition of heat preservation after welding. |
PDF Full Text Request