Pulsed submerged arc welding process in order to reduce the hydrogen input during the welding of high-strength fine-grained structural steels

Abstract

The utilization of high-strength fine-grained structural steels for applications in steel construction, vehicle construction, and pipeline construction is increasing continuously. In addition to the substantial weight savings by reducing the wall thicknesses, the resource consumption and thus the production costs can be reduced considerably by utilizing these steels in welded structures. One problem resulting from the use of a submerged arc welding process for such applications is the danger of hydrogen input, particularly due to the use of the welding fluxes. In this study, the decrease in the hydrogen input into the weld metal of high-strength fine-grained structural steels was investigated by using a submerged arc welding process in a pulse-modulated form of direct current. In this respect, it was possible to observe that the cavity is not formed up to its final size due to the constant change between a pulse condition and a basic condition within the basic phase. This results in a smaller cavity volume with a lower partial hydrogen pressure on average and thus also in a reduction in the contact area to hydrogen sources.