Analysis of Lack of Fusion in Welds at Water Heaters

Abstract

The paper treats a weld discontinuity called lack of fusion, which is frequently a cause of leakage of a water heater. The heater was produced by MAG welding using two wires (twin arc welding). The paper states some reasons for the occurrence of lack of fusion, i.e. the arc blow effect, an inappropriate gun position, uncontrolled movement of the weld pool, too low energy input, an improper joint preparation. The defect is illustrated in a macrograph of a weld produced at the water heater with twin wires in a shielding gas. Welding with twin wires is schematically represented with a circumferential welded joint between the end and shell of the water heater.

Keywords

• lack of fusion
• leakage of the water heater
• welding with two wires
• arc blow