Welding repair technology for nodular cast iron trolley

The invention relates to the technical field of metal smelting, in particular to a nodular cast iron trolley welding repair technology which comprises a nodular cast iron trolley welding repair method which comprises the following steps that firstly, external tensile stress is eliminated, a main beam opposite to a weld joint needing to be repaired is heated, and the weld joint needs to be repaired; the side beam is expanded by heating so as to open the fracture of the side beam; secondly, the fractures are expanded, an upper flange position wedge block and a lower flange position wedge block are plugged into an upper flange plate and a lower flange plate at the fractures of the side beams respectively, and the fractures are expanded for the second time in the original state. The working background, the stress structure distribution, the fracture reason and the heat treatment research of the nodular cast iron trolley are analyzed and researched; the stress problem is solved by adopting different heating modes