Estudo do ZTA de aços API X80 para tubulações através de ensaio de emissão acústica e teste de implante.

Abstract

The development of new High Strength Low Aloy pipeline steels considers more severe mechanical stresses requirements and toughness. The employ necessities led to thermal treatments suppression and superior weldability. The weldability improvement demands lower carbon contends so those new steels need hardening mechanisms that use a carbon smaller amount. One of the viable alternatives is the ultra-low carbon bainitics steels – ULCB, where the hardening mechanisms involve large dislocations densities, substitutional elements presence and globular bainite and ferrite mixed microstructures. To the HAZ ULCB study implant tests, microstructure analyses, fracture analyses and acoustic emission analyses were done. The results relationship with a conventional perlitic steel indicates superior weldability for bainític steel.