Influence of Service Time on the Microstructure and High Temperature Mechanical Properties of T23 Boiler Tube

Abstract:

The influence of long time service on the microstructure and high temperature mechanical properties of T23 steel was studied by optical microscopy, scanning electron microscopy, transmission electron microscopy and tensile testing machine. Results showed that lathy bainite ferrite disappears with the increasing service time, both the size and number of the carbides increases, and M₂₃C₆ carbides transform into M₆C carbides rich in W element. The service process also has a significant influence on the recovery. Sub-grains were found at the grain boundaries with little dislocations in the matrix after 27448 h service time. After running for 27448 h the microstructure degradation of T23 steel is serious. High temperature tensile properties of T23 are closely related to the alloy aging degree. The reasons for the decrease of high temperature mechanical properties after long time service included microstructure degradations such as the increase of both the size and quantity of M₂₃C₆ carbides, the transformation of M₂₃C₆ to M₆C, the desolution of Cr,W,and Mo elements, the decrease of the dislocation density and the occurrence of the sub-grains.

• Periodical: Materials Science Forum (Volume 898)
• Pages: 711-718
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.898.711
• Online since: June 2017
• Authors: Cheng He*, Bao Liang Shi, Wen Sheng Li, Jian Ping Zhao, Kai Xu, Yang Liu, Ai Ren, Yan Li
• Keywords: Aging, Mechanical Properties, Microstructure, Service Time, T23 Steel

References

[1] Y. Sawaragi, T. Kan, Y. Yamadera, F. Masuyama, T. Yokoyama, N. Komai (Eds. ), Proceedings of the 6th International Conference on Materials for Advanced Power Engineering, Liege ForschungszentrumJulich GmbH, Aachen, 1998, p.61.

[2] K. Miyata, M. Igarashi, Y. Sawaragi, ISIJ International 39(1999) 947-954.

[3] K. Kucharova, V. Sklenicka, M. Kvapilova, M. Svoboda, Mater. Charact. 109(2015) 1-8.

[4] M. Igarashi, M. Yoshizawa, H. Matsuo, O. Miyahara, A. Iseda, Mater. Sci. Eng. A. 510–511(2009)104-109.

[5] Z.S. Yu, M. Nie, S.F. Hou, et al, Foundry. Technol. 32(2011)465-470. (in Chinese).

[6] Z.S. Yu, M. Nie, S.F. Hou, et al, Thermal. Power. Generation. 41(2012)7-12. (in Chinese).

[7] M. Nie, Z.S. Yu, C.R. Zhou, Pressure. Vessel. Technol. 28(2011)1-4. (in Chinese).

[8] Y.Q. Deng, L.H. Zhu, Q.J. Wang, F.M. Zou, Heat. Treat. Metal. 32(2007)21-26. (in Chinese).

[9] Y.Q. Deng, L.H. Zhu, Q.J. Wang, F.M. Zou, J. Iron. Steel. Res. 19(2007)46-50. (in Chinese).

[10] H.C. Zhao, R.H. Ling, J.M. Jia, J.C. Zhao, Pro. Chin. Soc. Electrical. Eng. 31(2011)107-133. (in Chinese).

[11] A. Zieliński, G. Golański, M. Sroka, P. Skupień, Mater. High. Temp. 33(2016)154-163.

[12] J.E. Hong, G. Feng, Metal Materials and Training in Power Plant, China Machine Press, Beijing, 2012, 139-140.

[13] Z.H. Gong, W. Ding, D.F. Wang, Heat. Treat. Metal. 38(2013)78-81. (in Chinese).

[14] S. Esmaeili, D. J. Lloyd, W. J. Poole, Acta. Mater. 51(2003)2243-2257.

[15] L.H. Zhu, X.M. Ma, J. Mater. Sci. Technol. 19 (2003)126-128.