STUDIES ON WELDING PROCEDURE OF 9Cr-IMo VNb STEEL PIPE UNDER SHIELDED METAL ARC AND TIG WELDING PROCESSES

Abstract

Welding of modified 9Cr-lMo steel pipe has been carried out by SMAW and TIGW processes. The microstructure of the weld and HAZ of the weldments are studied under optical microscope and correlated with the preheating and Post weld heating temperatures. Hardness behaviour across the weld has been studied and average hardness of the weld and different regions of HAZ are estimated and correlated with the preheating and post weld heating temperatures. The tensile properties of the weldments are also studied and correlated to the Preheating and PWHT temperatures. At different PWHT the tensile properties of the SMA and TIG weldments are compared, where the preheating was kept constant