Low alloy steels are essential for the construction of
power plants and are normally employed for
temperatures up to about 550°C. They are normally used
for fabrication of critical components such
water walls, superheaters, reheaters and piping. In new
power plants these materials represent
important fraction of all materials employed and
therefore significant effort has been invested to
improve their characteristics, in particular creep
strength, ductility and weldability.
Grade 23 is one of the most successful results of such
development. Its balanced alloying (0.07C-
2.25Cr-1.5W-V-Nb) has increased significantly the creep
resistance in comparison to grade 22, yet
permitting to skip the PWHT on thin sections. With the
aim to develop the weld metal for the grade
23 in particular, leading European industries, research
centres and utilities have joined effort within
the EU project ALoAS to achieve this target.
The effect of the chemical composition of SMAW and SAW
consumables on creep, ductility and
long term stability of welded joints has been
investigated. This has required a thorough
characterization of the microstructures of the base
materials and welded joints, as well as of the
long term properties at high temperatures.
The results are presented and discussed on weld metal
development, microstructural stability and
the methodology to evaluate the suitability of the
consumables for the actual applications.
|Conference||11th International Conference of Creep and Fracture of Engineering Materials and Structures, CREEP 2008|
|Period||4/05/08 → 9/05/08|