Original scientific paper

Secondary hardening of low-alloyed creep-resistant steel welds

P. Mohyla ; Faculty of Mechanical Engineering, VSBTechnical University of Ostrava, Czech Republic
Z. Kubon ; Materials and Metallurgical Research, Ltd., Czech Republic
R. Cep ; Faculty of Mechanical Engineering, VSBTechnical University of Ostrava, Czech Republic
A. Janasek ; Faculty of Mechanical Engineering, VSBTechnical University of Ostrava, Czech Republic
I. Samardžić ; Josip Juraj Strossmayer University of Osijek Mechanical Engineering Faculty in Slavonski Brod, Croatia

Abstract

The T24 steel represents the new generation of low-alloyed creep resistant steels with higher creep resistance and lower carbon content. It was designed as prospective material for membrane waterwalls of ultra super critical (USC) power plants, enabling to avoid preheating and post weld heat treatment (PWHT) during welding. However, our investigations concerning secondary hardening of vanadium containing low-alloyed steels show that non-tempered welded joints undergo a significant increase in hardness during exposure to operating temperature. The results then imply that PWHT of T24 steel welds is necessary and this idea is at present supported by the occurrence of several troubles with new installations of USC blocks in Europe.

Keywords

T24 steel; 14MoV6-3 steel; welds; mechanical properties; post weld heat treatment

Hrčak ID:

104366

URI

https://hrcak.srce.hr/104366

Publication date:

1.1.2014.

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