The HAZ microstructure and toughness of 3 kJ/mm multipass welds in Ti microalloyed steels

TWI Industrial Member Report Summary 380/1988

By D J Sparkes

Background

A programme of work has been carried out to determine the HAZ microstructure and toughness of recently produced steels. Three materials were studied, all of which had a microalloying addition of titanium, with either vanadium or niobium also present, and a yield strength of approximately 350 N/mm². Multipass submerged-arc welds were produced at an arc energy of 3 kJ/mm as typical of industrial practice. The as-welded HAZ microstructure was examined using both optical and electron microscopy, and the toughness was assessed using Charpy and CTOD test methods.