The mechanism of acicular ferrite in weld deposits

Research has shown that the acicular ferrite microstructure in steel weld metal, which provides an optimum combination of strength and toughness, is indeed intragranularly nucleated bainite. It is possible to maximize the content of acicular ferrite by increasing the intragranular nucleation sites while maintaining a critical weld metal cooling rate and the steel hardenability. This paper highlights recent research related to nucleation and growth of acicular ferrite during decomposition of austenite.