What is the exact definition of ovality and out of roundness? Any spec/code which contains definitions and measuring methods for both of them say for pipes of API 5L grade? Thanks and regards
Sayee Prasad R
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ASME Y14.5M-1994 defines circularity (a.k.a. roundness) and its associated tolerance control as follows:
6.4.3 Circularity (Roundness). Circuìurity is a condition of a surface where:
(a) for a feature other than a sphere, all points of the surface intersected by any plane perpendicular to an axis are equidistant from that axis;
(b) for a sphere, all points of the surface intersected by any plane passing through a common center are equidistant from that center.
6.4.3.1 Circularity Tolerance. A circularity tolerance specifies a tolerance zone bounded by two concentric Circles within which each circular element of the surface must lie and applies independently at any plane described in (a) and (b) above. See Figs. 6-8 and 6-9. The circularity tolerance must be less
than the size tolerance, except for those parts subject to free state variation. See para. 6.8.