Elimination of starting pores in manual shielded-metal arc welding

Abstract

The paper studies the influence of the amplitude-time parameters of the welding current modulation at the initial moment of welding on the value of starting porosity. The authors investigated the butt welds of two identical 17GS plates were investigated. The dependence of starting pore formation on the value and duration of the modulation of the welding current, as well as its polarity were revealed using radiation introscopy of deposited weld metal. The results showed that stabilization of the transfer of electrode metal occurs in a shorter time when using a hot start. With the right choice of the hot start mode, the danger of the electrode sticking is completely eliminated, which in turn will reduce the number of ignitions of the arc discharge and, hence, the starting porosity.