Ancor Pipeline Integrity

The presence of high hardness bands in the area affected, adhesion failures of the coating, and existence of slag in the welding applied in 2013 were the main causes of the cracks that originated the leak in the first place.

Analysis and results:

1. Visual inspection of the removed section of the fault zone: a visible open crack, secondary tracks, and mild corrosion were observed.

2. Stereoscopic macrography of the fracture surface of the pipe: Presence of corrosion products, pitting in the heat affected zone, and slag inclusions were observed.

3. Metallography of the crack zone and the opposite (healthy) zone: Welding defects, presence of corrosion in the crack and weld defects such as porosities and inclusions were detected.
4. Fractography, Micrograph: There is a fine fracture surface with a river mark, which is evidence of brittle fracture by cycling.
5. X-Ray Scattering: Presence of SULPHUR and CHLORINE in significant quantities, coming from the soil (wastewater).

6. Microhardness measurements (weld, base metal and heat affected zone): Base material 2013 pipe (NA, NB) with considerably lower hardness than 1967 pipe.

7. Cathodic protection - On and Instant Off soil potential readings: Formation of hydrogen bubbles in the crack due to cathodic protection and acid soil (H2S).

Back

Page updated

Google Sites

Report abuse