Low-temperature high-construction steel thick plate welding method

The invention provides a low-temperature high-construction steel thick plate welding method, which belongs to the technical field of thick plate welding, and comprises the following steps: carrying out special welding process evaluation, compiling an operation instruction book, and determining welding process parameters; a protective shed is erected in the welding area; preheating before welding: preheating a welding area through a heating piece, wherein the lowest preheating temperature is 60 DEG C; a multi-layer and multi-pass welding method is adopted, and the interlayer temperature ranges from 100 DEG C to 150 DEG C; and post-welding heat preservation, wherein after welding is finished, post-heating heat preservation treatment is conducted on a weld joint. Through the process steps of arrangement of the protective shed, preheating before welding, interlayer temperature welding and heat preservation after welding, the quality of a welding seam is improved to the maximum extent, welding residual stress and