TAILIEUCHUNG - Effect of temperature on microstructure and mechanical properties of superheater steel pipe in thermal power plant
This paper presents an experimental investigation of the effect of heating temperature on microstructure and mechanical properties of the superheater steel (grade P22). The steel samples were cut from a new industrial pipe and heated to 500, 600 and 700 oC. The obtained results showed the distribution of ferrite and pearlite, a slight increase in the grain size and degradation of the strength as increasing the temperature. | Journal of Science & Technology 127 (2018) 067-071 Effect of Temperature on Microstructure and Mechanical Properties of Superheater Steel Pipe in Thermal Power Plant Nguyen Thu Hien, Bui Anh Thanh, Nguyen Van Tan, Phung Thi To Hang, Bui Anh Hoa Hanoi University of Science and Technology - No. 1, Dai Co Viet Str., Hai Ba Trung, Ha Noi, Viet Nam Received: March 14, 2017; Accepted: June 25, 2018 Abstract In thermal power plant, the failure of superheater steel pipe depends on working time, temperature and pressure of the steam. This paper presents an experimental investigation of the effect of heating temperature on microstructure and mechanical properties of the superheater steel (grade P22). The steel samples were cut from a new industrial pipe and heated to 500, 600 and 700 oC. The obtained results showed the distribution of ferrite and pearlite, a slight increase in the grain size and degradation of the strength as increasing the temperature. It was concluded that the temperature causes the microstructural change and decreasing strength of superheater pipe, resulting in damage of this part under long time service and high pressure of the steam. Keywords: thermal power plant, superheater steel pipe, microstructure, mechanical properties, grain size 1. Introduction Most1parts of the electricity generating equipments in power plants work at elevated temperature and high steam pressure, including boiler, turbine and connected system of tubing and piping. The generating equipments operate with steam pressures in the range of 20 MPa or even more and the steam temperature is also high in the range of 600 °C [1]. Since superheater steel pipes work in high temperature and pressure, the failure (crack, rupture, bulge, etc) occurs and causes operating discontinuation of the plant. According to the ASTM alloy designation, grade P22 or steel based on chromium and molybdenum are widely used in boilers and piping. This steel has been used successfully in power plant
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