pipe integral threaded joint formed by a male element and a female element respectively placed on the external surface and on the internal surface of two truncated cone - shaped parts of the threading having the same conicity value and being radially spaced , both being respectively divided by annular shoulders which are parallel and orthogonal with respect to the pipe axis . they are provided two sealing surfaces , one of them being cone - shaped and the other being spherical . after the screwing of the two elements said two annular shoulders are in contact . each male and female element comprises , respectively along its external and internal surface , a circumference cavity placed between a part of the threading and the annular shoulder in order to allow the expansion of the lubricating fat .