Development of Welding Materials for High Heat Input Welding Compatible with Thick Steel Plates of 460 MPa Yield Point Class for Very Large Container Ships

Abstract

Electrogas arc welding with high efficiency (Two-electrode Vibratory Electrogas Arc Welding, 2E-VEGA® process) and flux-cored wires for the 2E-VEGA process have been developed. They can be applied to YP460 MPa class extremely thick steel plates for very large container ships. The travel speed of the developed 2E-VEGA process is about twice as high as that of the ordinary 1E-VEGA process. Weld metal obtained with the present process and the present wires satisfied the target requirements of YP (yield point or proof stress) ≥ 460 MPa, TS (tensile strength) ≥ 570 MPa, vE−20 (−20 °C Charpy absorbed energy) ≥ 53 J and Hv (hardness number) ≤ 210 Hv in Vickers scale, even when 30 kJ/mm arc energy welding for 51 mm-thick plates was conducted. Using the present process and the present wires, sufficient fracture toughness of joints welded with high arc energy can be obtained.