摘要
某石油化工厂对换热器管程进行打压试验时发现严重泄漏。采用化学成分分析、力学性能试验、金相检验、扫描电镜分析等方法,对换热器泄漏失效原因进行了分析。结果表明,管程、壳程介质中均含有S2-,Cl-,造成换热器下端管程内外壁的点腐蚀;同时,缠绕管在应力和腐蚀介质的共同作用下,从内壁向外发生应力腐蚀开裂,最终导致换热器腐蚀泄漏而失效。
A petrochemical plant found serious leakage in the tube pass of a heat exchanger when conducting pressure test on the heat exchanger. The leakage failure cause of the heat exchanger was analyzed by the methods of chemical composition analysis,mechanical property test,metallographic inspection,SEM analysis,etc. The results show that there are S2-and Cl-ions in the media in both the tube pass and shell,which cause pitting corrosion on the inner and outer walls of the tube pass at lower end of the heat exchanger; At the same time,under the joint action of tensile stress and corrosive medium,the stress corrosion cracking occurs from the inner wall outward,eventually leading to failure of the heat exchanger due to corrosion leakage.
引文
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