Heat treatment effect on the corrosion rate, microstructure and mechanical properties of X60 pipeline steel

In this study, experimental investigations were executed to find the heat treatment effect of two different temperatures (250 °C and 650 °C) on the corrosion rate, microstructure, and mechanical properties of X60 pipeline steel. The obtained results were investigated using diverse instrumental methodologies such as Optical Microscopy, microhardness test, and potentiodynamic polarization measurements. Different microstructure phases appeared in the heat-treated specimens such as fine-grained ferrite, polygonal ferrite, ferrite structure with small islands of pearlite, retained austenite also have been found on this steel. Microhardness test shows that there a change in the hardness of the specimens. The microhardness values increased with increasing from the 250°C and then return to decrease again in 600°C. The polarization tests results show that the corrosion rate of the metal studied during the treatment at 250 and 650 ° C has a minimum value. The best corrosion resistance was obtained from heat treatment at 250°C. The heat treatment can change the mechanical characteristics and corrosion resistance properties of X60 steel.