Practice Questions Flashcards
Which of the following is true about corrosion?
A) it requires two different metals in contact with each other.
B) it requires acids to occur
C) it is natural and destructive
D) it occurs worse in very dry locations
C) it is natural and destructive.
Question:
Which of the following are necessary for corrosion to occur to a metal?
A) two dissimilar metals joined or touching each other
B) located in water or buried in soil
C) a anode, a cathode, electrical conductor (metal path) and electrolyte
D) stray electric currents
Answer:
C) an anode, a cathode, electrical conductor (metal path), and a electrolyte
Question: Which of the following metals are passivated (become corrosion resistant) by forming an oxide layer? A) steel B) stainless steel C)wrought iron D) cast iron
Answer:
B) stainless steel
Which of the following is the type of corrosion that occurs during graphitization of cast iron? A)galvanic corrosion B)stray current corrosion C)differential environmental corrosion D)dealloying
Answer
D) dealloying
Which of the following is the type of corrosion that occurs if two different metals joined to each other are placed in seawater? A) galvanic corrosion B) stray current corrosion C) concentration cell corrosion D) dealloying
Answer
A) galvanic corrosion
Which of the following is a structural feature usually found when differential environment corrosion is found? A) welds B) crevices C) corners D)water traps
Answer:
B) crevices
In which of the following situations is stray current corrosion most likely to occur to a steel pipe?
A) pipe buried close to an electric railway
B) pipe is buried close to the ocean
C) pipe in air in an industrial environment
D) pipe located inside a water tank
Answer:
A) pipe is buried close to an electric railway
Which of the following is a mechanism by which coatings may protect steel surfaces from corrosion?
A) by converting cathodes to anodes
B) by forming passive oxides on their surfaces
C) by forming a barrier to electrolytes
D) by making surfaces smoother
Answer:
C) by forming a barrier to electrolytes
Why should welds be ground before painting?
A) to increase the corrosion resistance of the steel
B) to improve their appearance
C) to make it easier to apply a smooth continuous paint film
D)to separate anodes and cathodes
Answer:
C)to make it easier to apply a smooth, continuous paint film.
What happens when uniform corrosion occurs?
A) the conductivity of the electrolyte remains very constant
B) the temperature of the electrolyte remains very constant
C) the anodes and cathodes reverse themselves periodically
D) the steel is protected from the light
Answer:
C) the anodes and cathodes reverse themselves periodically
Why is surface prep of steel before painting important?
A) it accelerates the curing of the primer
B) it provides good bonding of the primer
C) it permits application of a more attractive coating finish
D) it permits application of the coating at lower temps
Answer:
B) it provided good bonding of the primer
Which of the following surface imperfections is produced during cutting of the steel? A) crevices B) burrs C)pits D)spatter
Answer :
B) Burrs
Which of the following is most likely to occur if a thin film of grease or oil remains on a cleaned steel surface before coating?
A) osmotic blistering of the coating system
B) slow curing of primer coat
C) poor adhesion of primer coat
D) discoloration of primer coat
Answer:
C) poor adhesion of primer coat
Which of the following best describes mill scale?
A) iron oxide formed on steel surface during hot-rolling process
B) burrs formed on edges during their milling(rounding by grinding)
C)rust scale produced by steel weathering in a chemical environment
D) scale formed by grinding of rough steel surfaces to level them
Answer:
A) iron oxide formed on steel surfaces during hot rolling process
Which of the following is best used to remove only loose rust, loose mill scale, and loose paint from steel surfaces? A) detergent washer B) hand or power tool cleaning C) abrasive blasting D) water jetting
Answer:
B) hand or power tool cleaning
