Influence of rotation frequency and rotation diameter on mechanical properties and microstructure of weld metal produced by MCAW-RE

Abstract

The MCAW process with rotating electrode (MCAW-RE) is a variation of the conventional gas metal arc welding process, which a metal-cored wire is submitted to a rotational movement along a pre-established diameter. This process enhances narrow gap welding, since the rotational motion of the electrode allows the electric arc to reach peripheral regions of the groove, preventing lack of fusion on the sidewall. As a result, reduced costs and superior productivity compared with the conventional GMAW process are obtained. The limited literature about this process is focused on the operational characteristics, and works studying the mechanical properties are not available. Thus, this work evaluates the mechanical and microstructural properties of weld metals obtained by the MCAW-RE process in order to allow a decision about its technical feasibility to replace the GMAW process in industry. Initially, beads on plate weld tests were performed with varying rotation frequency and rotation diameter, in order to determine the parameters to be used in welded joints. High-strength steel weld metals were obtained by welding performed in steel plates with dimensions of 500 × 300 × 10 mm. Mechanical tests and metallographic examination were carried out in samples removed transversally to the weld bead. The results showed that the impact toughness of the weld metals can achieve the requirements for several industrial applications. The results showed that the GMAW process with rotating electrode-cored wire has a high potential for replacement of the GMAW in industrial applications.