尿素生产装置中高压冷凝器的腐蚀研究

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。

A STUDY OF CORROSION OF THE HIGH PRESSURE CONDENSER FOR PRODUCING UREA

The corrosion behavior of the stainless steel lining of the upper tube tank in the high pressure condenser was studied by meas of optical microscope, transmission electron microscope,scanning electron microscope and electron probe, and the causes of corrosion are discussed in this paper.Results of examination showed that two types, of corrosion, i. e., pitting corrosion and stress corrosion cracking, occurred on the 316L stainless steel lining under conditions of urea production. The microcracks of the stress corrosion cracking were initiated at the bottom of pits, aad the macro-cracks observed on the lining surface were in fact constituted by a serie s of pits that were close to one another.