Korosi Retak Tegang pada Pipa Superheater Ketel Uap yang Baru Dibangun [Stress Corrosion Cracking of Cage Superheater Tubes of a Newly Built Boiler]
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Abstract
A number of cage superheater tubes of a newly built steam boiler have been leaking during boiler’s first start-up commissioning. Leaking occurred when the boiler had just reached a pressure of 23.7 barg and temperature 4050 C from the intended operating pressure of 53 barg and temperature of 4850C. Type of failure and factors that may have caused the leakage of the cage superheater tube are discussed in this paper. The metallurgical assessment was conducted by preparing a number of specimens from the as received leaked cage superheater tube. Various laboratory examinations were performed including macroscopic examination, chemical composition analysis, metallographic examination, hardness test and SEM (scanning electron microscopy) examination equipped with EDS (energy dispersive spectroscopy) analysis. Results of the metallurgical assessment obtained show that the leaked cage superheater tubes have been experiencing stress-corrosion cracking (SCC) caused by the combined effect of corrosion and tensile stress. The corrosion agent that may have been responsible for the occurrence of SCC in the tube was mostly due to caustic sodium (Na) and other elements in a lesser extent such as Ca, Cl, S and P.
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References
R. Viswanathan, “Damage mechanism and life assessment of high temperature components”, ASM International, Metals Park, Ohio, pp. 183, 1989.
“Boiler condition assessment guideline,” EPRI (Electric Power Research Institute), 4th edn, Palo Alto, June 2006.
D. N. Adnyana, “Short-term localized overheating pada sebuah pipa ketel uap,” Atlas Kegagalan dan Kerusakan pada Komponen Mesin dan Peralatan Industri, vol. 1, pp.53-65, 2016
Saha, H. Roy, and A. K. Shukla, “Failure investigation of a final superheater tube in a 140 MW thermal power plant,” Journal of Failure Analysis and Prevention, vol. 15, no. 2, pp.184-189, 2015. DOI : 10.1007/s11668-015-9928-5
Madinah, D. N. Adnyana, and Hasan, “Kerusakan pada superheater steam tubes dari sebuah water tube boiler akibat long-term overheating,” Prosiding Seminar Nasional Teknik Mesin SNTM ISTN, 2015, pp.1-17.
M. N. Ilman, M. Prihajatno, and Kusmono, “Analysis of a failed primary superheater tube and life assessment in a coal-fired power plant”, Journal of Failure Analysis and Prevention, vol. 15, no. 2, pp. 200-204, 2015. DOI : 10.1007/s11668-015-9932-9
M. Yamauchi, N. Nishimura and M. Fujita, “Damage and remaining life assessment of boiler components”, Proceedings Seminar on Coal-Fired Boiler Research and Technology, 1993, pp.71-98.
API RP 571, “Damage mechanism affecting fixed equipment in the refining industry,” 1st edn, American Petroleum Institute, Washington DC, pp.138-143, 2003.
D. N. Adnyana, “Stress-corrosion cacking in an nickel-base alloy preheater expansion bellows,” Majalah Metalurgi, vol. 29, no. 3, pp. 235-244, 2014.
ASM Handbook, “Failure analysis and prevention”, ASM International, Material Park, Ohio, vol. 11, pp. 163-171, 1998.
ASME,”Boiler and pressure vessel code, Sect. II Part D,” The American Society of Mechanical Engineers, New York, pp. 2- 5, 2007.
