Automatic marking system and method for flat head of spiral submerged arc welding pipe

The invention belongs to the technical field of spiral seam submerged arc welding pipe production, particularly relates to an automatic marking system and method for a flat head of a spiral submerged arc welding pipe, and aims at solving the problems that existing manual flat head operation equipment is high in labor intensity and low in working efficiency. The system comprises a flat-head trolley, a first sensor arranged in the advancing direction of the flat-head trolley, a second sensor arranged on the flat-head trolley, a marking sensor and flat-head equipment, the first sensor is configured to trigger the flat-end trolley to start to move forwards when detecting that the steel pipe is conveyed to the rotating device; when the second sensor is configured to detect the pipe end of the steel pipe, the flat-end trolley executes a deceleration action; the mark sensor is configured to stop the flat-end trolley at a specified flat-end position when a slate pencil mark arranged at the flat-end position on the st