The addition of an appropriate amount of nitrogen to F51 stainless steel not only improves the pitting and SCC resistance of the steel, but also does not significantly reduce the plastic toughness due to the severe coarsening of the grains in the heat affected zone of the weld, and is also insensitive to welding hot cracks. Therefore, the corrosion resistance and mechanical properties of the heat affected zone of the weld are improved. The SCC resistance, wear corrosion resistance and corrosion fatigue resistance in many media are better than those of austenitic stainless steel [1-5]. In particular, the SCC resistance in a Cl-containing environment is particularly excellent [6]. The H2S SCC resistance is better than that of S30403 and S31603. The Socket Welding Coupling is composed of a socket, a socket, a bending part, a socket slot, etc., and it is characterized in that there is a socket slot in the socket, and the socket and socket are respectively located at both ends of the curved part; Compared with the prior art, the design is reasonable, the operation is simple, the practicability is strong, and the operation quality and convenience are improved.Socket Welding Coupling can be widely used in pipes of different diameters, including single-way, three-way, four-way, etc., and can also be used for water meters and valves. Due to the use of socket structure, the pipe joint reduces the cost, installation, use,maintenance is very convenient, and at the same time has a very high leakage prevention ability, which has a great market prospect.