Welding nails belong to fasteners with high strength and rigidity. Welding nails are short for cylindrical head welding nails for arc stud welding. The welding nails are of nominal diameter Ф 10 ~ Ф 25 mm and total length before welding is 40 ~ 300 mm.  Solder studs have a manufacturer's identification mark made of convex characters on the top surface of the head. Solder studs are widely used.