一段炉转化炉管的组织性能分析与评估

采用化学成分分析、着色渗透探伤分析、电子探针分析、显微组织分析、力学性能及高温持久性能分析等方法,对大型合成氨一段炉竖琴管排运行1.0×105h的转化管进行综合分析和评估。结果表明：转化管化学成分符合技术要求,宏观组织正常,显微组织形态良好,内外表面轻微腐蚀;经高温持久性能在L-M曲线中拟合外推,该管的剩余寿命远大于2.2×104h;炉管虽使用1.0×105h满足了工艺要求,但壁厚太大,影响热效率,同时内径小,限制了触媒和流量;因此,为提高效率,建议在今后的设计中采用性能较好的材料ZG50Ni35Cr25NbM。

Analysis and Evaluation of Microstructures and Properties of Conversion Tube

Comprehensive analysis and evaluation of a conversion tube in a large ammonia synthesized apparatus was carried out after service for one million hours by chemical composition analysis,electron microprobe analysis,color penetration testing analysis,macro and micro structure analysis,room-temperature and high-temperature mechanical properties analysis and high-temperature durable property analysis.The results show that the chemical composition meets the technical requirements,the macro and micro structures are normal,and the corrosion of inner and outer surface is slight.The residual life of the tube is much greater than 2.2×104 hours by fitting extrapolation of durable high temperature property in the L-M curve.Although HK40,the material of the furnace tube,meets the technological requirements,but the thicker wall affects the thermal efficiency.At the same time,the smaller internal diameter limits the catalyst and flow.So ZG50Ni35Cr25NbM is a good choice for increasing efficiency in the future design.