Welding method for reducing welding deformation of large casting

The invention relates to the technical field of casting welding, in particular to a welding method for reducing welding deformation of a large casting. A welding method for reducing welding deformation of a large casting comprises the following steps that a chilling block base plate is installed on the back face of the repair welding position of the casting to be welded, then a shape follow-up chilling block is placed on the casting to be welded, and then repair welding is conducted on the repair welding position; the repair welding comprises the steps that in the repair welding process, the temperature of a welding area is measured, when the temperature of the welding area exceeds 300 DEG C, welding is stopped, and when the temperature of the welding area is cooled to 60-70 DEG C, welding continues till welding is completed. According to the welding method disclosed by the invention, the deformation problem in the welding process of the large casting can be greatly reduced by adopting a cold iron and welding