T122钢在服役前后的组织演变和性能评价

Microstructure evolution and performance evaluation of T122 steel before and after service

采用SEM、TEM及高温蠕变测试等实验方法,研究了某电厂锅炉四级过热器出口用T122管材服役前和在585~610℃服役56000 h后的组织和力学性能。结果表明:经过长时间高温服役后,T122管材的板条马氏体组织索氏体化严重,析出相聚集、长大明显,力学性能也出现较大程度下降,高温蠕变曲线及Larson-Miller参数预示服役后的管材寿命急剧缩短;考虑到T122管材服役过程中组织劣化严重,剩余服役寿命的预测并不能完全依赖于有限时间内的高温蠕变试验。

The microstructure and mechanical properties of T122 steels used for superheater tube of the boiler before and after 56000 h of service at 585-610 ℃ in a power plant were studied by means of SEM,TEM,and high temperature creep test.The results show that after a long-term high-temperature service,the lath martensite of the T122 steels is seriously transformed into sorbite with the precipitates aggregated and coarsened obviously,and the mechanical properties also worsen greatly.High temperature creep curves and Larson-Miller parameters indicate that the residual life of the T122 steels after service is sharply shortened.Considering the serious deterioration of the structure in the service of the T122 steel pipe,the prediction of the remaining service life cannot depend entirely on the high temperature creep test in finite time.