High pressure welding fittings (or High pressure pipe fittings in English) A105 and A182 steel are used in pipelines with pressure levels from class 3000 PSI, 6000 PSI, up to 9000 PSI. These are specialized accessories used for pipeline systems of petroleum, compressed air, shipbuilding, hot steam… Used to connect branches of pipeline systems. Requirements for working pressure of accessories are very high. Including: Coupling, sleeves, sleeves, sprues, branch connections, internal thread connections, external thread connections, pipe end caps