Oil and gas industries including lower carbon energy — Full ring ovalization test method for the evaluation of the cracking resistance of steel line pipe in sour service

This document gives a method for determining the resistance to cracking of steel pipes in sour service.

This test method employs a full-scale test specimen consisting of a short length of pipe (a ‘full ring’), sealed at each end to contain the sour test environment within. The test method applies to any pipe; seamless, longitudinally welded (with or without filler), helical welded, and to girth welds between pipes.

NOTE 1 The specimen is usually a pipe but can also consist of flange neck or section of a bend, or other tubular component or a combination of the above.

NOTE 2 This test method can also be used for corrosion resistant alloys (CRAs).

The method utilizes ovalization by mechanical loading to produce a circumferential stress, equal to the target hoop stress, at two diametrically opposite locations on the inside surface of the test specimen. The test specimen is then subjected to single sided exposure to the sour test environment.

NOTE 3 The test also allows measurement of hydrogen permeation rates.