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Mechanical properties of T23 steel welded joints without post-weld heat treatment for fossil fired boilers

Published online by Cambridge University Press:  21 November 2016

Xue Wang ,
Yong Li ,
Huijun Li ,
Chao Yang  and
Qing-xu Yang
Xue Wang*
Affiliation:
School of Power and Mechanics, Wuhan University, Wuhan 430072, China
Yong Li
Affiliation:
School of Power and Mechanics, Wuhan University, Wuhan 430072, China
Huijun Li
Affiliation:
Faculty of Engineering and Information Sciences, University of Wollongong, NSW 2522, Australia
Chao Yang
Affiliation:
Jiangsu Frontier Electric Technology Co., Ltd., Nanjing 211102, China
Qing-xu Yang
Affiliation:
Jiangsu Frontier Electric Technology Co., Ltd., Nanjing 211102, China
*
a) Address all correspondence to this author. e-mail: [email protected]
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Abstract

Microstructures of new heat-resistant steel grade T23 welded joint without PWHT and its corresponding mechanical properties including creep were investigated to clarify its premature failure mechanisms in the large water wall panel of the advanced power plant boiler. The results show that the T23 steel GTAW welded joint in a wall thickness of 6.5 mm without PWHT exhibits high tensile strength, good ductility, and sufficient impact toughness, while the hardness of the WM is higher than the maximum permitted value of 350 HV due to the large amount of un-tempered martensite formed during the cooling process of welding. This WM in as-welded condition has higher creep rupture strength but poorer rupture ductility than the tempered BM. Poor rupture ductility taken place in the WM results from inter-granular cracking during creep exposure and is not related to the second hardening because no hardness rise occurs in the fractured WM compared with as-welded condition. The paper does not specifically investigate the effect of service exposure but simulates the failure of WM by a creep test. The main point is that the WM has low creep ductility, especially at a stress concentration.

Keywords

microstructureweldingsteel
Type
Articles
Information
Journal of Materials Research , Volume 31 , Issue 24 , 28 December 2016 , pp. 4000 - 4008
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Copyright
Copyright © Materials Research Society 2016 

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References

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