Influence of Current Type on the Composition of C-Mn-Ti-B MMA Deposits and of Welding Position on the Mechanical Properties of C-Mn-Ni MMA Deposits

TWI Industrial Member Report Summary 317/1986

By D J Abson

Background

The work described in this report is part of an investigation into the influence of procedural variations on microstructure and mechanical properties for manual metal arc (MMA) deposits. The following studies were undertaken:
i. Following previous work on C-Mn and C-Mn-Ni MMA electrodes, the influence on deposit oxygen and nitrogen content both of arc voltage and of employing different types of current supply (d.c. positive, d.c. negative and a.c.) was examined for three C-Mn-Ti-B MMA electrodes.
ii. The chemical composition, microstructure and mechanical properties were examined of multipass butt welds, welded with the same C-Mn-Ni electrodes as employed in the previous study, and employing a d.c. negative power supply. Whereas welding was previously carried out in the flat position, vertical-up welding was employed in the present work.