Practical forged flange-type ball valve fabrication method

A method of forming a flange type ball valve comprising the steps of:

• a) forging a fluid inlet seat having a first flange, a first center through hole and a first friction welding portion;
• b) forging a ball valve seat having a second flange, a second center through hole, a ball valve chamber, and a second friction welding portion such that a wall thickness of the second friction welding portion is equal to a wall thickness of the first friction welding portion;
• c) friction welding the ball valve seat and the fluid inlet seat together at the first and second friction welding portions so as to form a first sub-assembly;
• d) removing any protruding internal and external welding beads from the first sub-assembly;
• e) forging a position limiter seat with a third flange, a third center through hole and a third friction welding portion;
• f) forging a fluid outlet seat with a fourth flange, a fourth center through hole and a fourth friction welding portion, such that a wall thickness of the fourth friction welding portion is equal to a wall thickness of the third friction welding portion;
• g) friction welding the position limiter seat and the fluid outlet seat together at the third and fourth friction welding surfaces so as to form a second sub-assembly;
• h) removing any protruding internal and external welding beads from the second sub-assembly;
• i) forming a first sealing washer groove in the first sub-assembly adjacent to the ball valve chamber;
• j) forming a second sealing washer groove in an end of the second sub-assembly;
• k) forming mounting holes in the first, second, third and fourth flanges, the mounting holes in the second and third flanges being aligned with each other;
• l) forming a ball seat in the ball valve chamber;
• m) forming a handle insertion hole in the ball valve seat communicating with the ball valve chamber;
• n) inserting first and second sealing washers in the first and second sealing washer grooves;
• o) placing a ball valve in the ball valve chamber;
• and,
• p) attaching the first and second sub-assemblies by fastening elements passing through the mounting holes in the second and third flanges such that the first and second sealing washers contact the ball valve.