TEP WCI 4

State 3 common measures to control corrosion

• apply coating

• use corrosion inhibitor

• use of corrosion coupon

• use of UT

What type of cracking normally found in 300 series  SS?

• Transgranular cracking
• Extraterrestrial cracking
• hydrogen cracking

• stress corrosion cracking

Factors of stress corrosion cracking in 300 series SS?

• temperature

• tensile stress

• chloride content

• hydrogen level

What is happening when iron and Aluminium are connected in seawater?

• Aluminium acts as the anode and corrodes while iron acts as the cathode and remains protected.
• Both iron and Aluminium corrode equally in seawater.
• There is no reaction between iron and Aluminium in seawater.
• Galvanic corrosion occurs, with iron acting as the anode and corroding while aluminium acts as the cathode and remains protected.

How are corrosion inhibitors acting on piping internal?

• By increasing the rate of corrosion
• By reducing the flow of liquid inside the pipes
• By causing chemical reactions with the pipe material
• By forming a protective layer on the inner surface of the pipes

To obtain the best adhesion of the paint to the metal surface:

• Clean and prepare the surface, apply a primer designed for metal surfaces before painting.
• Paint over rusted areas without removing the rust
• Use a primer designed for wood surfaces
• Apply the paint directly without any preparation

Corrosion monitoring by coupons and probes allows the operator:

• To measure the rate of corrosion on metal surfaces over time.
• To evaluate the efficiency of the corrosion inhibitor

• To estimate the service life of the equipment

• To check if the line is in good condition

What facilitates pitting (corrosion) of stainless steel in humid marine atmosphere?

• Carbon dioxide

• Bacteria

• Water

• Chlorides