Behaviour of dissimilar weld joint of steels FB2 and F during long-term creep test

5th International Conference Recent Trends in Structural Materials

Kasl, J.^1 ; Jandová, D.^1 ; Kanta, V.^1

Výzkumný A Zkuebni Ustav Plze S.r.o., Tylova1581/46, Plze

301 00, Czech Republic^1

关键词: Chromium carbide;    Creep rupture strengths;    Creep strengths;    Dissimilar weld joint;    Fine grained heat affected zone;    Larson-Miller parameter;    Lower temperatures;    Microstructure development;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/461/1/012036/pdf
DOI  :  10.1088/1757-899X/461/1/012036

来源: IOP

【 摘 要 】

Creep test to the rupture of both the dissimilar weld joint made of FB2 and F martensitic steels and the base materials was carried out at temperatures ranging from 550 °C to 650 °C in the stress range from 70 to 220 MPa. Creep rupture strengths of the weld joint and the base materials were evaluated using Larson-Miller parameter. Assessment of microstructure development and changes of hardness was correlated with the creep strength. Critical zones of creep damage were determined. At lower temperatures and higher stresses the weld joint ruptured in the base material of F steel unaffected by welding, while at higher temperatures and lower stresses rupture occurred in the intercritical heated and fine-grained parts of heat affected zone of steel F. During creep at temperatures above 575 °C Laves phase precipitated in all parts of the weld joint and especially in the heat affected zones. Coarse Laves phase particles and their clusters with chromium carbides served as nucleation centres for cavities. As the fine grained heat affected zone of F steel was the softest part of the weld joint, many cavities originated and initiated causing failure of samples.