Energy / Processes
Technical Paper

Improved weldability and criterion for reliability of high strength pipes steels

International Seminar on Welding of High Strength Pipeline Steels

Welding criteria assessment has been investigated based on techniques for welding thermal cycle simulation and analysis of kinetics of austenite transformation within the heat affected zone. Results from an assessment of the heat affected zone (HAZ) low temperature toughness when exposed to increased heat input welding for heavy wall pipe, and susceptibility to cold cracking during decreased heat input welding are presented. The impact of alloying elements - nickel, chromium, vanadium and molybdenum in niobium microalloyed steels, on ductile-brittle failure parameters is demonstrated. Vanadium and molybdenum microalloying of niobium-based steel results in HAZ embrittlement. Optimum post welding cooling rates have been determined, for which the HAZ toughness is ensured at temperatures down to minus 30 оС in niobium-based steels with nickel or chromium additions. (AU) Copyright © 2013 Companhia Brasileira de Metalurgia e Mineração (CBMM) All Rights Reserved
Technical Paper (PDF 2,99 MB)