Steel tube joint close inside welding system, cantilever body cover die and steel tube joint close inside welding method

The invention belongs to the technical field of welding devices, relates to a steel tube joint close inside welding system and aims at solving the problem that separation distances of welding grooves formed in a section to be welded cannot be kept consistent. The steel tube joint close inside welding system comprises a joint close hydraulic machine frame, a joint close trolley and an inside welding machine and further comprises a resisting part, wherein the resisting part comprises a fixing portion, a cantilever portion connected with the fixing portion and extending into a steel tube and a cantilever groove arranged on the joint close trolley. The cantilever portion comprises a cantilever body and a rolling wheel mechanism arranged on the cantilever body and rolling in the cantilever groove, wherein the cantilever body comprises a carrier roller section of a carrier roller for pushing the steel tube towards the direction of the joint close hydraulic machine frame. By means of the technical scheme, the technical problem can be effectively solved.