Correlation between EBSD quantification and dilatometry examination of an X70 steel

Abstract

In order to design controlled rolling schedules, it is critically important to understand phase transformation and to have detailed transformation temperatures of the phases to achieve the desired microstructure. Samples of API 5L X70 pipeline steel were soaked at 1100°C for 5 minutes in a dilatometer and then continuously cooled at constant rates from 0.5 to 100°C/s to develop a range of different microstructures. The microstructures of all specimens were examined by optical and electron microscopy (SEM). Three specimens with different cooling rates were further analyzed through EBSD to better differentiate the microstructures to enable the development of a CCT diagram for the design of rolling schedules.