对某超临界锅炉末级过热器T91钢管的爆管原因进行了分析。结果表明: 该T91钢管爆管是由于管内壁偏厚的氧化皮剥落, 在下弯头处堆积造成管内介质流量减少,引起钢管过热所致。针对该问题, 通过对T91等铁素体锅炉钢管进行内壁氧化皮厚度测量, 并根据测量结果采取相应措施, 可大大减少或避免由于氧化皮剥落、堆积而引起的爆管事故。

The bursting reason of T91 steel tube in supercritical boiler final superheater was analyzed. The results show that the steel tube bursting resulted from the thick oxide scale of inner wall peeled and deposited at the lower elbow of the tube, which caused the flow area in the tube decreasing and resulted in superheating. The number of bursting of T91 ferritic steel tubes caused by peel-off and accumulation of oxide scale could be decreased greatly or even avoided by measuring the oxide scale thickness and adopting corresponding measures according to the measure results.