热电厂用20G珠光体钢的球化机理及寿命预测

Spheroidizing mechanism and life prediction of 20G pearlite steel used for power plant

针对广泛应用于压力容器管线、蒸汽管道等常用的20G钢,采用高温加速时效方法模拟了其高温长时间使用条件下的微观组织和硬度变化。结果表明:20G钢在高温加速时效过程中主要发生珠光体球化和碳化物聚集于晶界处,随着时间的增加珠光体球化速率逐渐变慢;建立了20G钢在加速时效过程中晶粒尺寸变化公式。基于硬度测量和微观组织分析,通过将硬度值与LarsonMiller参数结合预测了材料使用寿命。

High temperature aging method was used to accelarate the aging process of 20G steel which is mainly used for pressure vessel, steam pipes and so on. The evolution of the microstructure and mechanical properties （ hardness） was systematically investigated under the acceleration of the aging process. The results show that during the aging process, pearlite is spheroidized gradually and carbide is gathered in the grain boundary. The rate of pearlite spheroidization gradually is reduced with the high temperature aging time increasing. The formula of the grain size changing with the aging time is established. Based on the hardness measurement and the analysis of the microstruture, the service life of the material is predicted through the combination of the hardness value and the Larson-Miller parameters.