Heat exchanger tube head structure capable of ensuring root penetration welding

The utility model relates to the technical field of a welding joint of a tubular heat exchanger tube plate and a heat exchange tube, in particular to a heat exchanger tube head structure capable of ensuring root penetration, which comprises a tube plate and a heat exchange tube, the tube plate is provided with a tube hole, the end part of the heat exchange tube penetrates into the tube hole, and a port of the heat exchange tube is recessed into the surface of the tube plate by 0.5-1mm. An inverted-frustum-shaped welding groove is formed in an end opening of the pipe hole, the angle of the welding groove ranges from 35 degrees to 50 degrees, and the height of the welding groove ranges from 1.5 mm to 2.5 mm. According to the improvement, an annular step which is transversely arranged is arranged at the bottom of the welding groove around the periphery of the pipe hole, and a downward-concave fillet is arranged at the transition position of the annular step and the side wall of the welding groove. As the step is