论文部分内容阅读
通过对尿素合成塔外壁带有裂纹的层板试样进行宏观检查、金相组织分析、断口扫描电镜分析、化学成分分析、力学性能测试、硬度及厚度的测定,并结合外层板材料分析、层板间的应力分析以及尿塔工作介质的分析,最终可得出:外层板出现多处裂纹是由于有较大拉伸应力的低合金钢外层板在空气与雨水中的氨、保温层中的Na+、K+、S2-以及漏入检漏蒸汽中的Na+、K+等腐蚀性物质共同作用下发生应力腐蚀造成的。
Through the macroscopical inspection, the microstructure analysis, the fracture scanning electron microscopy analysis, the chemical composition analysis, the mechanical property test, the determination of the hardness and the thickness of the cracked veneers on the outer wall of the urea synthesis tower, and in combination with the analysis of the outer plate material, Stress analysis between the plies and the analysis of the working medium of the pylons finally leads to the following: the occurrence of multiple cracks in the outer plies is due to the ammonia in the air and rainwater of the low-alloy steel plies with larger tensile stress, Na +, K +, S2- in the layer, and Na +, K + and other corrosive substances leaking into the leak detection steam are under the stress corrosion.