In welded pipe manufacturing, which method involves forming a heated plate into a tube-like form?

The method that involves forming a heated plate into a tube-like form is known as the electric fusion method. In this process, the edges of a heated steel plate are brought together and fused without the addition of filler metal. The heat necessary for this fusion comes from the electrical energy applied, allowing the plate to take on a tubular shape.

This method is particularly efficient for creating pipes since it can handle thicker materials and results in strong, continuous welds that maintain the integrity of the pipe. The process is advantageous for its ability to produce a high-quality seam and is often used for applications requiring durable and pressure-resistant tubes.

The other methods listed vary in application and process. For example, the electric resistance method involves using electrical resistance to heat the edges of the metal until they melt and bond but typically does not focus solely on the formation of a tube from a heated plate in the same manner. The double submerged-arc method and manual welding methods also differ significantly in technique and result, focusing more specifically on different welding techniques rather than the initial formation of a pipe from a plate.