Nano-mechnaical analysis of mechanical characteristics of a ultra high strength pipeline steel

Abstract

The mechanical characteristics in micro-phases of two different-typed API X-100 pipeline steels (ultra high strength steels recently developed for the transmission of crucial oil and natural gas) were evaluated by using nanoindentation technique. The steels` microstructures mainly consist of equi-axed/acicular ferrite and bainite. Nanoindentation experiments were made on each phase, and the hardness impressions were analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results are discussed in terms of the microstructural effects on the deformation and hardening mechanisms in the steels.