Role of Martensite-Austenite Component of Bainitic Structure in Formation of Properties of Pipe Steel. 1. Effect of Parameters of TMT

The effect of parameters of hot rolling and controlled cooling on formation of the martensite-austenite component of bainitic and ferritic-bainitic structures in a pipe steel of strength class K60 is studied. The Pocket Jaw module of a Gleeble 3800 facility is used to reproduce the modes of rolling and controlled cooling of the steel. The deformed samples are subjected to an x-ray diffraction analysis. The content of untransformed austenite and martensite in the structure of the steel is determined. It is shown that the volume fraction of the martensite-austenite component varies from 0.5 to 8% depending on the studied parameters of the thermomechanical treatment. The accumulated strain is found to play the dominant role in formation of the martensite-austenite particles and to determine the fraction of acicular ferrite.

Automated summary

The effect of hot rolling and controlled cooling parameters on the formation of the martensite-austenite component in bainitic and ferritic-bainitic structures of K60 pipe steel was studied. Experimental results showed that the volume fraction of the martensite-austenite component varied from 0.5% to 8% depending on the parameters of the thermomechanical treatment. The accumulated strain was found to play a dominant role in the formation of martensite-austenite particles and the determination of the acicular ferrite fraction.