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用光学显微镜、透射电镜、扫描电镜以及电子探针技术对高压冷凝器上管箱内衬所出现的腐蚀形貌进行了研究,并探讨了产生腐蚀的原因。结果表明,用SUS316 L不锈钢制造的内衬在尿素生产的条件下主要发生了两种类型的腐蚀:点腐蚀和应力腐蚀开裂;应力腐蚀开裂起始于点腐蚀坑的底部。内衬表面所呈现的宏观裂纹实际上是由一系列相距很近的点腐蚀坑串联而成。
The corrosion morphology of the tube liner on the high pressure condenser was investigated by optical microscope, transmission electron microscopy, scanning electron microscopy and electron probe technique. The causes of the corrosion were also discussed. The results show that two types of corrosion mainly occur in the production of urea: the pitting corrosion and stress corrosion cracking; the stress corrosion cracking starts at the bottom of the pitting corrosion pit. Macrocracks on the lining surface are actually formed by a series of pitting pits in close proximity.