MICROSTRUCTURE CHANGES OF P92 WELD DURING CREEP EXPOSURE

This work is a contribution to the research of modified heat resistant steel P92. This steel is currently one of the best modified chromium steels in terms of achieved values of creep rupture strength. The article is focused on microstructure investigation of P92 weld after creep deformation. Up to date results of creep rupture test of P92 welds are presented here too. The microstructure in the as welded condition and after long-term creep exposure (26.000 hours/600 degrees C) of P92 welds has been investigated and microstructural parameters were determined. Results of intercritical zone of heat affected zone (HAZ) are compared with parameters of parent material, which is not influenced by welding. Results of TEM analyses reveal deteriorating effect of welding procedure on microstructure od P92 welds during subsequent creep exposure.