Socket Weld Actuated Stainless Steel Ball Valves
The ends of the valve are socketed to receive plain-end pipes and the joints secured by circumferential welds. Socket weld ends are used usually on the smaller sizes of valves for higher pressure-temperature applications in pipelines not requiring frequent dismantling and on severely corrosive services for which threaded ends would be unsuitable.
Butt Weld Stainless Steel Actuated Ball Valves
In this case the ends of the valve are bevelled to match machined bevels at the ends of the mating pipes and a circumferential weld is made at the abutted mating bevels. 'Backing rings', which are basically sleeves fitting inside the pipe, are sometimes used to align the pipe and valve bores. They also prevent 'icicles' and weld spatter from entering the pipeline. Butt-weld ends are generally used only for the more severe applications where frequent dismantling is not required.