Method and equipment for manufacturing inner container of water heater and water heater

The invention discloses a manufacturing method and manufacturing equipment of a water heater inner container and a water heater. The manufacturing method of the water heater inner container comprises the steps that a coiled material is blanked to form a plate; the plate is subjected to tubulation forming treatment to form a first tubular part, and a gap is formed in the peripheral wall of the first tubular part; straight seam welding treatment is conducted on the seam of the first tubular part to form a second tubular part with the closed peripheral wall; and the second tubular part is cut off to form a plurality of inner container barrel bodies. According to the manufacturing method of the water heater inner container, before straight seam welding, the plate is formed into the first tubular part, then straight seam welding is conducted on the first tubular part through the straight seam seam pipe technology, after long straight seam welding is completed, the second tubular part is cut off and then serves as