Comparison of weld quality of unalloyed boiler steels obtained by changing arc process for the root pass

Abstract

This paper considers the effect of applied welding process over the weldment quality. Unalloyed boiler steels such as P265GH (EN) and S355 J2 (+N) (EN) are used as base material respectively. Welding is performed as multipass with SMAW (111), GMAW (131 and 135) and SAW (121). Four different groups of welded speciments are created, depending of the root pass. In the first, second and third group, the root pass is done with 111, 131 and 135 and filling passes with 121, while the fourth group is completely performed by 121. All welds are inspected radiographically and metallographically before submited to further evaluation. Quality assessment of weldments is determined through classical mechanical investigations such as tensile and bending test, Vickers hardness along the weldment and Charpy impact test. Attained results indicate that hybrid arc welding guarantees safer performance and general quality of welded joint.