Metal expansion joints and corrugated expansion joints have some similarities in function and structure, but there are some differences.

The metal expansion joint is mainly a flexible structure arranged on the container shell or pipe to compensate for the additional stress caused by the temperature difference and mechanical vibration. As a free elastic compensation element, metal expansion joint has the advantages of reliable operation, good performance and compact structure, and has been widely used in chemical industry, metallurgy, nuclear energy and other departments. Its varieties include elbow expansion joints, bellows expansion joints and casing expansion joints. Among them, bending pipe expansion joint is to bend the pipe into U-shape or other shape, and make use of the elastic deformation ability of the shape to compensate. Bellows expansion joint is a kind of expansion joint made of metal bellows, which can expand and contract along the axis direction and also allow a small amount of bending.

Corrugated expansion joints are flexible elements that can effectively compensate axial deformation due to thermal expansion and contraction, or compensate axial, transverse and angular displacements of pipes, conduits and containers. It takes advantage of the effective expansion and contraction deformation of its working body bellows to absorb the dimensional changes of pipes, conduits, containers, etc. The structure of the corrugated expansion joint consists of bellows (an elastic element) and attachments such as end tubes, brackets, flanges and conduits.

While metal expansion joints and corrugated expansion joints overlap somewhat in function and structure, their main differences lie in construction and materials. Metal expansion joints may include various types, such as elbow and bellows types, while corrugated expansion joints specifically refer to structures that use bellows as a core element. Furthermore, corrugated expansion joints focus more on describing their ability to expand, contract and deform using bellows, while metal expansion joints describe their functions and applications as compensating elements more broadly.