... Stud Flange 4.Sizes: 15A - 1000A Welding neck flange (API,ANSI standard)TYPES: Welding Neck Flanges, Slip on Flanges, Threaded Flanges, Socket ... Flanges, Lap Joint Flanges, Ring Joint Flanges, Long Welding Neck Flanges, Figure 8 BlanksPRESSURE GRADE: Class150,Class300,Class600,Class900 ... and the use of forged or cast parts for the design and production. Welding Neck Flange (API petroleum accessory)