Sensitization induced stress corrosion failure of AISI 347 stainless steel fractionator furnace tubes

Swaminathan, J and Singh, Raghuvir and Gunjan, M K and Mahato, B (2011) Sensitization induced stress corrosion failure of AISI 347 stainless steel fractionator furnace tubes. Engineering Failure Analysis, 18 (8). pp. 2211-2221.

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Austenitic stainless steel tubes are used as furnace tubes in petrochemical industries mainly because of their corrosion resistance and mechanical strength. AISI 347 grade stainless steel is used as furnace heater tubes in the fractionator of hydrocracker unit. Even though this stainless steel is stabilized with the addition of niobium thus preventing sensitization related corrosion failures, operational and maintenance errors may result in premature failures if conditions prevail. The present work reports the premature failure of AISI 347 grade fractionator furnace tubes after nearly 8. years of service. The failure occurred after shutdown. Carbonaceous deposits were found on the inner walls of the tube and circumferential cracks were found beneath the deposit. The service exposed 347 SS alloy tube was in the sensitized condition as confirmed by microstructure and double loop electrochemical potentiodynamic reactivation test. The tube material got sensitized possibly by localized overheating at the carbon layer deposited site. During shutdown of hydrocracker unit polythionic acid formation occurred possibly due to errors in shutdown procedures. Sensitized alloy 347 tube undergone polythionic acid induced intergranular stress corrosion cracking (PASCC). © 2011 Elsevier Ltd.

Item Type:Article
Official URL/DOI:
Uncontrolled Keywords:AISI 347 SS; Furnace tube failure; Polythionic acid induced stress corrosion cracking; Sensitization
Divisions:Corrosion and Surface Engineering
Material Science and Technology
ID Code:4222
Deposited By:Dr. A K Sahu
Deposited On:05 Nov 2011 11:56
Last Modified:21 Nov 2011 12:45
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