Welding method for high manganese steel liquid cargo hold of LNG (Liquefied Natural Gas) ship and high manganese steel liquid cargo hold

The invention provides a welding method for a high-manganese steel liquid cargo tank of an LNG (Liquefied Natural Gas) ship, which comprises the following steps of: S1, selecting high-manganese steel plates as base metal, butting the high-manganese steel plates, and treating a groove at the butting part; s2, matching a welding material, wherein the welding material is a flux-cored wire matched with the base metal; s3, welding is carried out by adopting a direct current reverse connection current type; performing multi-layer and multi-pass welding on the front groove by adopting CO2 gas shielded welding; after front groove welding is completed, carbon arc air gouging back gouging is conducted on the back face of the weld joint, and after the carbon gouging position is polished and smoothened, multi-layer and multi-pass welding is conducted on a back face groove; s4, after welding is finished, nondestructive testing is conducted within preset time; and determining that welding is completed after the detection r