Improved Type for Fatigue Strength Ferrule

This structure has the gas that forms during welding go through the upper part of the ferrule. The collar shape of the welded part becomes smooth, and the fatigue strength of the welded part is improved compared to current ferrules. This contributes to a longer lifespan for buildings and bridges.
In addition, it can limit the amount of metal powder (spatter) that occurs when welding, and it reduces the time needed for removal and cleaning. It is expected to reduce the burden for workers.