What are the major corrosion problems in boiler?
What is the impact of corrosion to boiler steel parts?
What is meant by “wet corrosion” and “dry corrosion”?
Describe and distinguish between “chemical” and “electrolytic” corrosion, which normally occur in a steam boiler.
What are some of the fireside corrosions and explain in detail.
What is pitting corrosion?
Is oxygen pitting dangerous?
What is high temperature corrosion?
Describe oxygen attack on boilers.
Describe electrochemical process of oxygen attack.
Describe the effect of temperature on corrosion in boiler.
What are the methods to control corrosion pitting in the boiler?
What is meant by stress corrosion? Where it is likely to occur in a boiler? Write a short note on how to prevent such a defect. NEW 2ND EDITION
Relate unexpected failure of steam boiler with regard to stress corrosion cracking. NEW 2ND EDITION
Describe the principle of cathodic protection. NEW 2ND EDITION
Cathodic protection can be achieved by the use of galvanic (sacrificial) anodes or by “impressed” current. Describe the two ways. NEW 2ND EDITION
Make a comparison between anodic and cathodic protection. NEW 2ND EDITION
What are the four (4) factors affecting corrosion resistance of a metal? NEW 2ND EDITION
What is the harmful effect of metal corrosion to a boiler shell? NEW 2ND EDITION
Internal and external corrosion usually take place in a vertical-tubular boiler. Explain and state the areas where internal and external corrosion take place. NEW 2ND EDITION
What is the difference between low-temperature corrosion and high-temperature corrosion? Give examples.
What are the conditions in boiler that promote caustic cracking to occur?
Describe how steam blanketing contributes to the development of caustic corrosion.
Describe how porous metal oxide contributes to the development of caustic corrosion.
What are the methods of preventing caustic cracking (embrittlement)?
What is galvanic corrosion?
What is the difference between corrosion and erosion?
What is erosion corrosion?
What is exfoliation corrosion?
What is hydrogen-induced cracking (HIC)?
What is water-wall corrosion in boiler?
What is cold end corrosion and how does it affect a boiler air heater, economizer and stack?
What is stress corrosion cracking (SCC)?
What are the differences between SCC and HIC?
Explain how concentration of caustic (NaOH) occurs during boiler operation.
In examining a package fire tube boiler, identify the areas or places where corrosion, pitting, and bulge are likely to occur. Explain the possible causes of such defects and suggest how such occurrence can be prevented.
What is after-boiler corrosion?
Where is internal corrosion most likely to occur in a vertical tube boiler and a locomotive boiler?
What is the difference between macroscopic corrosion and microscopic corrosion? Give examples for each type of corrosion.
What are the common process variables that influence corrosion?
What is the relationship between corrosion and scaling?
What is uniform corrosion?
What is crevice corrosion? Explain three (3) different ways of controlling or preventing crevice corrosion.
Explain what do you understand by the term “Dew Point”?
What is likely to occur if the flue gas temperature is too low?
How corrosion attacks economizer? How do you prevent corrosion attack in an economizer?