Investigation On Hot Corrosion Behavior And Performance Of Welded Joints Of T92 Steel Used In Power Plants

T92 steel is a new martensitic steel, which is used in superheater and reheater of power plant boiler in our country. This paper simulated the work environment of T92 steel in the laboratory. It aimed at studying the hot corrosion mechanism of welded joint of T92 steel. What's more, it studied the corrosion resistance of different areas of T92 welded joint. The conclusions are as follows:1) The course of hot corrosion can be divided into initial stage and steady stage. During the initial stage, the material is oxidized, the electrolyte is formed, the electrochemical corrosion occurs. During the steady stage, the corrosion reactions periodic occurred. The material is reduction.2) The deposit coats react with SO₂ and O₂, forming low-melting-point alkali iron tri-sulfates. It can be the electrolyte and material as the anode, electrochemical corrosion occurs.3) The mixed zone of T92 welded joint gets the most weight gain. It ranged by coarse grained zone, base metal, the weld, fine grained zone. It can be deduced that the influencing factors of the corrosion resistance of different regions of T92 welded joint are phase structure, distribution, grain size, and alloying extent.