Gas shield welding method for super-thick steel for ocean engineering

The invention discloses a gas shield welding method for ultra-thick steel for ocean engineering. A welding wire is welded on an ultra-high-strength steel plate by adopting gas shield welding; the groove is a single-sided asymmetric K-shaped groove, the angle of an upper groove is 40-45 degrees, the angle of a lower groove is 45-50 degrees, and the size of a truncated edge is 5-6 mm; the protective gas is CO2, and the gas flow is 18-25 L/min; the welding position is 3G, the preheating temperature before welding is larger than or equal to 200 DEG C, the interlayer temperature is 130-200 DEG C, and back gouging treatment is needed before back face welding; the welding speed ranges from 18 cm/min to 28 cm/min, the arc voltage ranges from 23 V to 33 V, the welding current ranges from 178 A to 230 A, and the welding heat input ranges from 13 kJ/cm to 32 kJ/cm; and post-heat treatment is performed at the temperature of 300-400 DEG C after welding, and the heating rate is 2.0-2.5 T/min. The welding method has the adv