Gas Metal Arc Welding of 9% Nickel Steel Using Ferritic Filler Metal Used for Building LNG Transport Tanker

Abstract

An investigation has been carried out to realize commercial application of welding of 9% Ni steel using ferritic filler metal having chemical composition similar to that of base steel, which was developed by the authors. The weldments having excellent notch impact properties and superior strength were obtained by gas metal arc welding. And the brittle fracture initiation characteristics before general yielding of the weldment was surveyed both experimentally by three kinds of the large scale type tests such as Welded Wide Plate Tension Tests, W-I Type Notched and Welded Wide Plate Tension Test and Deep Notch Test and theoretically based on the fracture mechanics. The safety to brittle fracture before general yielding was confirmed especially at LNG temperature.