MELO, J. B. C. A.; http://lattes.cnpq.br/7962147028271194; MELO, João Baptista da Costa Agra de.
Abstract:
The purpose of this work was to analyze the influence of the time and
temperature of relief stress thermal treatment on the hardness and impact resistance of a
welded joint of an API 5L X60 steel pipeline used for petroleum transmission. For this,
Vickers hardness and Charpy impact test at 253K (-20 C) were executed in specimens
extracted from weld metal, heat affected zone (HAZ) and base metal submitted to thermal
treatment at 823K (550 C) and 923K (650 C) for 1 hour and at 923K (650 C) for. lh, 5h, 8h
and 11 hours. The results indicated an increase of weld metal and HAZ impact resistance for
treatment of 1 hour at both temperatures, with larger efficiency at temperature of 823K
(550yC). However, it was observed a great decrease of metal base impact resistance at
temperature of 923K (650 C). A decrease of the impact resistance for all the welded joints
regions was observed for time higher than 8 hours at 923K (650 C), in spite of the stability of
hardness values.