目的 研究改进工艺热浸铝后的炼化加氢换热器管束在不同氯化铵环境下的耐腐蚀性能，并对其耐蚀机理进行分析。方法 采用改进的热浸铝工艺对20#钢、15CrMo钢和321不锈钢进行表面处理，利用光学显微镜、X射线衍射仪、扫描电镜和能谱仪对镀层厚度、组织和成分进行分析，采用氯化铵垢下腐蚀实验和高温高压釜模拟工况实验评价热浸铝镀层的耐氯化铵腐蚀性能。结果 20#钢、15CrMo钢和321不锈钢热浸铝层无表面缺陷，热浸镀铝层厚度均≥0.080 mm，镀层结构主要由纯Al层、Fe-Al合金层以及少量的Al2O3组成。在潮湿氯化铵条件下，20#钢和15CrMo钢的腐蚀速率均随着温度的升高而明显增大，80 ℃时的腐蚀速率分别达到21.6 mm/a和19.9 mm/a；321不锈钢有明显点蚀现象。热浸镀铝后，在相同介质中放置一个月，发现三种试样没有腐蚀现象出现。高温高压釜模拟工况实验后，热浸铝镀层表面同样也没有腐蚀现象发生。结论 采用改进工艺获得的20#钢、15CrMo钢和321不锈钢换热器管束热浸铝镀层质量符合国家标准要求，潮湿氯化铵垢下腐蚀实验和高温高压釜模拟工况实验结果证实，热浸铝镀层在氯化铵服役环境下具有良好的防腐性能。

The work aims to study the corrosion resistance of hydrofining heat exchangers tubes after improved hot-dipping aluminum treatment in different ammonium chloride environments, and analyze the corrosion resistance mechanism. 20# steel, 15CrMo steel and 321 stainless steel were treated by improved hot-dipping aluminum technology. The thickness, structure and composition of coatings were analyzed by optical microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The corrosion resistance in ammonium chloride of hot-dipped aluminum coating was evaluated by corrosion test under wet ammonium chloride and simulated service condition test of high temperature and high pressure autoclave. The obtained hot-dipped aluminum coatings on 20 # steel, 15CrMo steel and 321 stainless steel had no surface defects, and the thickness were all over 0.080 mm. The coating structure was mainly composed of pure Al layer, Fe-Al alloy layer and a small amount of Al2O3. Under the condition of wet ammonium chloride, the corrosion rates of 20# steel and 15CrMo steel increased obviously with the increasing temperature. The corrosion rates reached 21.6 mm/a and 19.9 mm/a respectively at 80 ℃. For 321 stainless steel, the pitting corrosion was obvious. After hot-dipped aluminum treatment, the surface of three samples had no corrosion found in the same medium for one month, and the hot-dipped aluminum coatings after simulated conditions in high temperature and high pressure autoclave did not have corrosion, either. The quality of hot-dipped aluminum coating of 20# steel, 15CrMo steel and 321 stainless steel hydrofining heat exchangers tubes by improved technology meets the national standards. These results of corrosion test under wet ammonium chloride and simulated service condition test of high temperature and high pressure autoclave confirm that the hot-dipped aluminum coating has good anti-corrosion performance in the service environment of ammonium chloride.