What is the difference between bolts and welded nails: there is no difference, just personal habits called different; the correct name is bolts.

Where to use welding nails in steel structure: 1, cup type foundation, in order to combine with concrete more firmly after the column is buried, use welding nails in the buried part of the column; 2, high-rise building steel structure columns, beams installed outside the bread cement, in order to combine with concrete firmly, columns, beams have to hit the welding nails. 3, floor beams have to hit the welding nails on the upper flange.