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Effect of weld heat input and creep strain on the elevated temperature and crack growth properties of austenitic steels
Author(s) -
Kanbach Helmut,
Detert Klaus,
Rukwied Armin
Publication year - 1989
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.198901662
Subject(s) - materials science , creep , incoloy , welding , metallurgy , austenite , embrittlement , ductility (earth science) , cracking , composite material , microstructure , corrosion
A potential material class for use at 600°C and more, e.g. for steam turbines with improved thermal efficiency, are austenitic steels. Using these steels with welded joints, it is to be considered that, by superposition of weld residual stresses and service stresses, extensive creep strains – and in the worst case crack formation – can occur locally. To assess the influence of these effects on service behaviour, different material states of CrNi‐steels and Incoloy 800 were investigated with respect to strength, ductility and, especially, to crack and creep crack growth in the temperature range around 600°C. It is shown that creep embrittlement, not microstructural changes as effected by weld heat input, causes heat affected zone (HAZ)‐reheat cracking. Creep embrittlement can be avoided by special design and fabrication rules.