12Cr1MoV主蒸汽管线改造工程中的金相组织研究

Study on Metallographic Structure of 12Cr1MoV Main Steam Pipeline in Reconstruction Project

某石化热电厂在工业管道定期检验中发现主蒸汽管道材质严重劣化后,对其进行整体更换。由于相关标准未规定入厂原材料的球化等级,考虑定期检验以及长时间使用后球化问题,将12Cr1MoVG材料入厂球化等级定为不低于2.5级。集箱、热成型弯管等原材料的球化趋势一般为外表面大于芯部,硬度变化趋势为外表面小于芯部。采用金相组织状态、现场宏观硬度检验对主蒸汽管线剩余寿命进行大致预测是方便可行、效率较高的。

A petrochemical power company replaced the main steam pipeline as a whole after it was found that the material quality of the main steam pipeline was seriously deteriorated during the periodic inspection of the industrial pipeline.Because the relevant standards do not stipulate the spheroidization grade of the raw materials,considering the periodic inspection and the spheroidization after long-term use,the spheroidization grade of the raw 12Cr1MoVG materials should be not less than 2.5.The tendency of spheroidization of raw materials such as header and hot-formed bend is generally that the outer surface is larger than the core,and the change trend of hardness is that the outer surface is smaller than the core.It is convenient,feasible and efficient to roughly predict the residual life of the main steam pipeline by metallographic structure state and on-site macro hardness test.