Look at the photos. State the corrosion type and describe it.
(1) (2)
(3)
(4)
(5)
(6)
(7) (8)
(9)
10. What is IT in each of these sentences?
1. IT
occurs in fast flowing liquids that have a high level of turbulence.
2. IT
occurs over the whole surface
3.IT
occurs in or around a break in the material
4. IT
occurs as pits in the metal surface
5. IT
occurs at or near the grain boundaries of the metal.
6. IT
occurs as cracks
7. IT
occurs as the joint action of mechanical stresses and corrosion.
Use the definitions to complete the following table. Comment on the items in the table.
FAILURE / FAULT
PROBABLE CAUSES
REMEDY
Pitting corrosion
Match the question about corrosion on the left with the answers on the right.
1.
Do we have any problems?
A.
That’s what I’m doing.
2.
I see, now what can be done?
B.
Somewhere, about 1km. from here.
3.
That’s crazy. It’s time to work!
C.
H’m, well I think, maybe, like the Moon surface.
4.
What section is damaged?
D.
How can I do it?
5.
Can you identify the area of corrosion on this section?
E.
Maybe, some corrosion.
6.
If you are so eager, tell me what does it look like?
F.
Had I time, even now.
7.
How long do you think it’ll take to test and measure it?
G.
Let’s paint it.
Now, put the dialogue in the right order and answer the questions.
1. Where does this conversation take place?
2. What is the situation?
3. Who is involved?
13. Read the following text “Cracks” and answer the questions.
1. What types of cracks exist?
2. What factors cause the formation of cracks?
3. What materials are more affected by cracks?
4. What types of cracks are shown on these photos?
5. What caused their formation?
Cracks
Crack characteristics can vary greatly depending on the cause of the crack, the materials being cracked, and the environment causing the cracking. The following photos show examples of crack profiles.
Isolated SCC and Colony SCC
Cracks may form as isolated cracks or within colonies. An example of an isolated crack is shown in the photos. Cracking within colonies may result in the cracks on the periphery of the colony being deeper then the cracks at the center of the colony. This may be observed because the effect of cracking within a colony environment may act as a stress relieving mechanism causing reduced crack growth for cracks located in the center of the colony while the cracks on the periphery continue to grow.
14. Read the information about “Applied coatings” and then the statements and circle T (True) or F (False)
Applied coatings
Plating, painting, and the application of enamel are the most common anti-corrosion treatments. They work by providing a barrier of corrosion-resistant material between the damaging environment and the structural material. Platings usually fail only in small sections. In this case, it is necessary to plate with a more active metal such as zinc or cadmium.
The corrosion control system for an oil and gas pipeline consists of two parts: the external coating on the pipeline and the cathodic protection. The primary purpose of the coating is to protect the pipe surface from its external environment. Coatings are also increasingly used to protect the internal surface of pipelines. Over the years the pipeline has been protected by various polymeric coatings. In the 1950s and 1960s, coal tar or asphalt coatings were applied. In the mid-1950s, mill-applied extruded polyethylene coatings were introduced. From the early 1960s to the early 1980s, polyethylene tape coatings were field applied.
1. Painting is the only anti-corrosion treatment
T
F
2. Anti-corrosion elements are obstacle materials
between corroded surface and structural material
T
F
3. Platings are excellent in small sections.
T
F
4. The corrosion control system includes two parts
T
F
5. A coating does not protect the pipe surface.
T
F
6. Coatings protect both external and internal pipeline
surfaces.
T
F
7. Polyethylene coatings were first applied in the 70s.
T
F
15. Match the questions about “Cathodic protection” on the left with the answers on the right.