The pipe ball joint includes a casing having a socket portion with a substantially spherical interior surface and a first pipe segment extending from the socket portion. The socket portion has an annular groove disposed adjacent the partially spherical interior surface. A ball pipe section includes a ball segment received in the socket portion of the casing and a second pipe segment extending from the ball segment. A seal assembly is received in the annular groove of the casing and is disposed against the ball segment of the ball pipe section. The seal assembly includes a plurality of nested seal rings that each include a concave face and a convex face.