Research of welding effect on creep damage of high temperature furnace tubes

Among the failure cases of high temperature components, premature failures of vveld-ments have taken a large percentage that indicates the detrimental effect of welding on structural integrity. In the present paper, a local damage mechanics approach is introduced to study the damage development and creep rupture of waisted cross-weld specimens and HK-40 furnace tubes due to the presence of a weld. It is illustrated that although the weldment belongs to a creep-hard weld, damage is prone to the weld in the later period of service life, creep dmage localization occurs, and the final failure takes place in the weld. Metallographical research also indicates that the weld may have a higher damage rank. It is thus concluded that the weldments may become the weak link in HK-40 furnace tubes.