Galvanized steel pipe connection method: thread, welding. Roll groove connection (1) Cracking of rolling groove welds 1. Flatten the inner wall welding rib of the pressure groove part of the nozzle to reduce the rolling groove resistance. 2. Adjust the axis of the steel pipe and the rolling groove equipment, and require the steel pipe and the rolling groove equipment to be level. 3. Adjust the grooving speed, the forming time of the grooving cannot exceed the specified time, and apply force evenly and slowly. Read More