Out Of Roundness / Ovality ASTM A999-2001 Volume 01.01

[Division]

Hello,

I am familiar with Ansi B16.9, where the out of roundness is the sum of absolute values of plus an minus tolerances.

I have a 10 inch pipe (OD 273,05mm) with Wall thickness 4,19mm. Can anyone tell me how to understand the out of roundness of ASTM A999. It says; " The differents in extreme outside readings (ovality) in any cross-section shall not exceed 1,5% of the specified outside diameter".

 

[WBH]

Ovailty measurments are usally taken on a horizontal and vertial planes on the OD of the pipe/vessel. These measurments are subtracted from each other, this is the differnce. The differnce is then divided by the OD of pipe/vessel, and converted to a percentage, this will give you a percentage of ovality. Measurements may be taken at several planes to determine the largest and smallest OD of the pipe with these measurements used for calculations.

 

[deanc]

See ASME SecVIII Div1 UG-80.