Description: There are nuts, cloud head, butt three parts. After the bar or pipe fittings forging ingot shaping by machining, its points of connection socket weld and threaded, socket weld pipe is inserted into the socket hole welding, therefore, is called "socket union ", threaded pipe connection is screwed into the screw connection, therefore, called" threaded union ", mainly manufacturing standards for ASME B16.11, MSS SP 83. Socket union by jack, socket, bearing slot etc., characterized in that the socket has a bearing slot, socket, socket are located at both ends; compared with the existing technology, reasonable design, simple operation and practical strong, improve the quality and convenience of operation