The invention discloses a submerged-
arc welding process for a T-type joint for an extra thick steel plate and belongs to the technical field of 
welding of extra thick plates. The process comprises the following steps of: before 
welding, pre-heating the extra thick steel plate to 100 to 150 DEG C; removing pollutants of oxides, greasy 
dirt and the like on the surface of the groove of the extra thick steel plate; bottoming the extra thick steel plate by submerged-
arc welding; forming systematical grooves and after the front face of the extra thick steel plate is bottomed, 
welding and filling; performing back gouging on the reverse side of the extra thick steel plate and welding and filling the reverse side; and filling welding wires on the front side of the extra thick steel plate and covering the side. The problems that manual bottoming efficiency is low, labor intensity is high, and heat 
cracking, undercutting, mechanical 
slag inclusion, large working amount of back gouging of the reverse side and the like are easily caused by submerged-
arc welding bottoming when the T-type joint of the extra 
thick plate of which the thickness is 50 to 150mm is welded are solved; by the selection of an appropriate groove form, the welding sequence, and 
welding process parameters, and 
slow cooling measures, 
slag is easy to clean in a filling weld pass, the working amount of back gouging is reduced, the 
welding deformation is reduced, the 
welding residual stress is reduced and the quality of a weld joint is guaranteed; and the submerged-arc 
welding process is easy to operate and implement, and is convenient to popularize.