Analysis of Lack of Fusion in Welds at Water Heaters

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

Analysis of Lack of Fusion in Welds at Water Heaters

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

Improvement of Energy and Materials Efficiencies by Introducing Multiple-Wire Welding

The paper deals with a study and comparison between welding with several wires in different shielding atmospheres and single-wire welding. The first part treats the equipment for multiple-wire electrode welding and a comparison between single-wire welding and twin-wire welding. The second part deals with the melting rate as a basis for determining the productivity of welding processes, and the third one with the energy efficiency as a criterion of cost-effectiveness of welding. Some results obtained regarding strength of submerged arc welded joints are shown