Production of 20 mm Thick API PSL 2 X60 and X70 Grade Plates from a Nb-Ti Microalloyed Steel

Abstract

T here are currently hundreds of thousands of kilometers long petroleum and natural gas pipelines installed worldwide and new lines are being installed continuously [1,2]. As the demand for petroleum and natural gas by the developed and developing countries has increased over time, the pipelines of larger diameter pipes that can work at higher operating pressures were required [2,3]. This necessitated the development of steel plates with higher mechanical properties from which these pipes could be produced [4].Pipeline steels should have high weldability since pipelines are installed by joining pipes to each other by welding. For this reason, pipeline steels must have low carbon content and low carbon equivalent values and this essentially implies ferritic microstructures [5,6]. As a way of having high strength, high ductility and high weldability at the same time, grain size refinement mechanism is utilized in pipeline steels. By decreasing the ferrite grain size, both strength and toughness can be si-Article History: