12Cr1MoV钢主蒸汽管道运行19万小时后的组织性能评定

Appraisal of microstructure and mechanical properties for the 12Cr1MoV steel main steam pipe after 190 thousand hours' running

采用金相观察、碳化物类型及成分分析、力学性能检测等试验手段,对运行了19万小时的电厂用12Cr1MoV钢主蒸汽管道进行组织与性能评定。结果表明,碳化物在晶界和晶内均发生聚集,其类型从运行前的M3C、MC转变为M3C、MC、M7C3、M2C,但晶粒和碳化物没有长大的迹象,且未发现使其性能严重恶化的M23C6和M6C型碳化物。室温下,其强度和冲击韧性有所下降,但塑性无明显变化;高温下强度下降,但塑性和冲击韧性有所提高。总之,该管道的组织和性能仅发生了轻度劣化,可以继续安全运行。

The microstructure and mechanical properties of 12Cr1 MoV steel main steam pipe after 190 thousand hours＇ running were appraised by means of microstructure observation, carbides analysis and mechanical property test. The resuits show that the types of carbides change from M3C and MC to M3C ,MC ,M7C3 and M2C ,but no M23C6 and M6C found which results in the properties deterioration. The aggregative carbides are observed both in the grain boundaries and within the grains, but no evidences indicate the growth of the grains and carbides. The strength and toughness at room temperature decrease, but the plasticity almost unchanges. The high temperature strength decreases, but the toughness and plasticity increase to a certain extent. In a word, the pipe was damaged to a small extent, so it can continue to be used safely.