Study on Tensile Creep Behavior of 12Cr1MoV Alloy Steel under High-Temperature Alkali Metal Salt Environment for Solar Thermal Power Generation

Jiahong He ,Jian Chen,Gang Wang,Kaijun Yang,Jiangyong Bao,Wei Li

doi:10.1155/2020/7095872

Abstract

The heat exchange tubes of solar thermal power generation work in molten salt environment with periodic temperature change. In order to reveal the tensile creep behavior of 12Cr1MoV pipeline steel under high-temperature alkali metal salt environment, the tensile creep behavior of 12Cr1MoV alloy under different applied load and reaction temperature in high-temperature alkali metal chloride salt environment was studied. The results show that the deformation of 12Cr1MoV alloy in 600°C, NaCl-35%KCl mixed salt environment is mainly controlled by diffusion creep; with the increase of stress, the creep life of 12Cr1MoV alloy decreases. The creep fracture mechanism of 12Cr1MoV alloy in 600°C, NaCl-35%KCl mixed salt environment is intergranular ductile fracture; the increase of temperature will enhance the activation and oxidation of the chlorine atoms, thereby accelerating the corrosion of the base metal and increasing the spheroidization speed of the pearlite matrix, and the creep deformation rate of the alloy increases with increasing temperature.

Highlights

IntroductionVarious factors that reduce the creep life of alloys by thermal corrosion, such as the generation and propagation of surface cracks, have been confirmed by previous studies
12Cr1MoV as an alloy material with high strength and good heat resistance [1,2,3] has been widely used in solar thermal power generation heat exchange tubes
The results show that the minimum creep rate will increase and the creep life will decrease under the corrosive condition

Summary

Introduction

Various factors that reduce the creep life of alloys by thermal corrosion, such as the generation and propagation of surface cracks, have been confirmed by previous studies. The creep fracture behavior of Nimonic-90 alloy at high-temperature and hot corrosion environment was studied by Gosh [10]. Suryanarayanan et al [11] indicated that the creep life of the material is reduced in different corrosion conditions, especially in the NaCl-Na2SO4 mixed salt. Bagui et al [12] show that the creep progress will be accelerated in mixed salt and high-temperature environment, but no significant effect on creep progress with different proportion of NaCl-Na2SO4 mixed salt. On He and Xiong’s point of view [13], it is interesting to note that creep deformation of microstructures in NaCl-40%Na2SO4 was the

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