Determination of the Bonding Behaviour of Carbon and Nitrogen in Micro-Alloyed Structural Steels

Abstract

The high technological requirements placed on large-diameter pipe steels can only be met in an economically feasible way by using micro-alloyed thermo-mechanically rolled steels. The thermo-mechanical treatment mainly aims at grain refinement. The purpose of the micro-alloying elements is to inhibit, by means of carbo-nitride precipitation, further growth of the austenite grain at high temperatures, thus contributing to the reduction of the ferrite grain size. In addition, precipitation hardening of the ferrite is aimed at. Optimization of a material in terms of high strength coupled with excellent toughness behaviour requires the purposeful utilization of the micro-alloying elements vanadium, niobium and titanium.