Development of banded microstructure in 34CrNiMo6 steel

Abstract

In this paper the development of a banded microstructure in hot-rolled 34CrNiMo6 steel which consisted of bainitic and martensitic bands is explained. The chemical compositions of the bands were measured with energy dispersive x-ray spectroscopy (EDS), which showed that the martensitic bands contained more alloying elements (Mn, Cr, Mo, Si) than bainitic bands. By using Oberhoffer reagent, the segregations of phosphorus were also revealed. These phosphorus segregations coincided with the positive segregations of the alloying elements. The continuous cooling transformation (CCT) diagrams of steel were calculated. They confirmed the formation of martensite in positive segregations and the formation of bainite in negative segregations.

Keywords

• 34CrNiMo6 steel
• metallography
• banded microstructure
• phosphorus
• CCT diagram