Analysis of the Cracking of the Fins of the Thin Tube in the Middle Partition Wall of the Boiler

During the inspection of the heating surface of No. 2 boiler in a thermal power plant, it was found that the fins of the thin tube in the middle partition wall were cracked. In order to find out the cause of fin cracking, a comprehensive experimental study was carried out on the thin tube of middle partition wall with fin cracking by means of appearance analysis, mechanical property analysis, chemical composition analysis and metallographic microstructure detection. The results showed that the fin cracking of thin tube in the middle wall of Chen 2 boiler was due to the large stress on the thin tube in the middle wall caused by the poor expansion of the tube screen during the operation, and finally the fin weld root which was easy to produce stress concentration cracks. It was recommended to find out the causes of the poor expansion of the thinning pipe of the middle partition wall on site, and at the same time, focused on the root of the nearby tube panel fin weld to check whether there was any cracking, and replaced the defects in time to prevent the similar cracking failure from happening again.