Senior Corrosion Technologist
1. Which of the following material properties is most important in
determining the suitability of carbon steel for high-temperature applications?
● A) Tensile strength
● B) Ductility
● C) Thermal conductivity
● D) Oxidation resistance
Answer: D) Oxidation resistance
Explanation: Oxidation resistance is crucial for high-temperature applications because it
prevents the steel from degrading due to reactions with oxygen at elevated temperatures.
2. Stainless steel's corrosion resistance is primarily due to which element?
● A) Carbon
● B) Chromium
● C) Nickel
● D) Molybdenum
Answer: B) Chromium
Explanation: Chromium forms a passive oxide layer on the surface of stainless steel, which
protects it from corrosion.
3. Which type of stainless steel is most suitable for marine environments?
● A) Ferritic
● B) Martensitic
● C) Austenitic
● D) Duplex
Answer: C) Austenitic
Explanation: Austenitic stainless steels, such as 316L, contain higher amounts of nickel and
molybdenum, which enhance their corrosion resistance in chloride-rich environments like
seawater.
4. What is the primary advantage of using carbon steel over stainless steel in
industrial applications?
● A) Higher corrosion resistance
● B) Lower cost
● C) Greater strength
● D) Better thermal expansion
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, Senior Corrosion Technologist
Answer: B) Lower cost
Explanation: Carbon steel is generally less expensive than stainless steel, making it a cost-
effective option for many applications where corrosion resistance is not critical.
5. MR0175 is a standard related to the resistance of materials to which
specific type of corrosion?
● A) Pitting corrosion
● B) Crevice corrosion
● C) Stress corrosion cracking
● D) Hydrogen sulfide corrosion
Answer: D) Hydrogen sulfide corrosion
Explanation: MR0175 is a standard that specifies materials and their properties for use in
environments containing hydrogen sulfide, which can cause sulfide stress cracking.
6. Which of the following describes the interaction of carbon steel with an
acidic environment?
● A) Carbon steel is resistant to acid corrosion.
● B) Carbon steel quickly forms a protective oxide layer in acidic environments.
● C) Carbon steel corrodes rapidly in acidic environments.
● D) Carbon steel undergoes passivation in acidic environments.
Answer: C) Carbon steel corrodes rapidly in acidic environments.
Explanation: Carbon steel is prone to rapid corrosion in acidic environments because the
protective oxide layer is unstable in acidic conditions.
7. In the context of material selection for corrosion resistance, what is the
significance of the term "galvanic series"?
● A) It ranks materials based on their density.
● B) It ranks materials based on their hardness.
● C) It ranks materials based on their corrosion potential in seawater.
● D) It ranks materials based on their melting point.
Answer: C) It ranks materials based on their corrosion potential in seawater.
Explanation: The galvanic series lists metals and alloys according to their electrochemical
potential in a specific environment, such as seawater, helping to predict galvanic corrosion.
8. Which property of stainless steel makes it more resistant to stress corrosion
cracking compared to carbon steel?
● A) High carbon content
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, Senior Corrosion Technologist
● B) High chromium content
● C) Low thermal conductivity
● D) High ductility
Answer: B) High chromium content
Explanation: The high chromium content in stainless steel enhances its resistance to stress
corrosion cracking by forming a protective oxide layer.
9. What role does molybdenum play in enhancing the corrosion resistance of
stainless steel?
● A) Increases hardness
● B) Improves tensile strength
● C) Enhances resistance to pitting corrosion
● D) Reduces thermal expansion
Answer: C) Enhances resistance to pitting corrosion
Explanation: Molybdenum improves the resistance of stainless steel to pitting corrosion,
particularly in chloride-containing environments.
10. Which metallurgical phenomenon occurs when two different metals are in
electrical contact in a corrosive environment?
● A) Pitting corrosion
● B) Galvanic corrosion
● C) Crevice corrosion
● D) Intergranular corrosion
Answer: B) Galvanic corrosion
Explanation: Galvanic corrosion occurs when two dissimilar metals are electrically
connected in a corrosive environment, leading to accelerated corrosion of the more anodic
material.
11. Which element is added to carbon steel to increase its hardenability?
● A) Sulfur
● B) Phosphorus
● C) Manganese
● D) Silicon
Answer: C) Manganese
Explanation: Manganese is added to carbon steel to increase its hardenability, improve
strength, and help remove oxygen and sulfur impurities during steelmaking.
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, Senior Corrosion Technologist
12. What is the primary reason for the susceptibility of carbon steel to
localized corrosion in chloride environments?
● A) High chromium content
● B) Presence of sulfides
● C) Lack of a passive film
● D) High carbon content
Answer: C) Lack of a passive film
Explanation: Carbon steel does not form a stable passive film in chloride environments,
making it more susceptible to localized corrosion such as pitting and crevice corrosion.
13. What effect does increasing the carbon content in steel have on its
weldability?
● A) Increases weldability
● B) Decreases weldability
● C) Has no effect on weldability
● D) Improves corrosion resistance
Answer: B) Decreases weldability
Explanation: Increasing carbon content in steel decreases its weldability due to the
formation of harder, more brittle microstructures, which can lead to cracking during welding.
14. Which stainless steel grade is most commonly used for food processing
equipment due to its high corrosion resistance and ease of cleaning?
● A) 304
● B) 409
● C) 430
● D) 316
Answer: A) 304
Explanation: Grade 304 stainless steel is widely used in food processing because it offers
good corrosion resistance, is easy to clean, and does not impart any taste to food products.
15. What is the primary characteristic of austenitic stainless steels that
distinguishes them from other types of stainless steel?
● A) Magnetic properties
● B) Ferritic microstructure
● C) High carbon content
● D) Non-magnetic properties
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1. Which of the following material properties is most important in
determining the suitability of carbon steel for high-temperature applications?
● A) Tensile strength
● B) Ductility
● C) Thermal conductivity
● D) Oxidation resistance
Answer: D) Oxidation resistance
Explanation: Oxidation resistance is crucial for high-temperature applications because it
prevents the steel from degrading due to reactions with oxygen at elevated temperatures.
2. Stainless steel's corrosion resistance is primarily due to which element?
● A) Carbon
● B) Chromium
● C) Nickel
● D) Molybdenum
Answer: B) Chromium
Explanation: Chromium forms a passive oxide layer on the surface of stainless steel, which
protects it from corrosion.
3. Which type of stainless steel is most suitable for marine environments?
● A) Ferritic
● B) Martensitic
● C) Austenitic
● D) Duplex
Answer: C) Austenitic
Explanation: Austenitic stainless steels, such as 316L, contain higher amounts of nickel and
molybdenum, which enhance their corrosion resistance in chloride-rich environments like
seawater.
4. What is the primary advantage of using carbon steel over stainless steel in
industrial applications?
● A) Higher corrosion resistance
● B) Lower cost
● C) Greater strength
● D) Better thermal expansion
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, Senior Corrosion Technologist
Answer: B) Lower cost
Explanation: Carbon steel is generally less expensive than stainless steel, making it a cost-
effective option for many applications where corrosion resistance is not critical.
5. MR0175 is a standard related to the resistance of materials to which
specific type of corrosion?
● A) Pitting corrosion
● B) Crevice corrosion
● C) Stress corrosion cracking
● D) Hydrogen sulfide corrosion
Answer: D) Hydrogen sulfide corrosion
Explanation: MR0175 is a standard that specifies materials and their properties for use in
environments containing hydrogen sulfide, which can cause sulfide stress cracking.
6. Which of the following describes the interaction of carbon steel with an
acidic environment?
● A) Carbon steel is resistant to acid corrosion.
● B) Carbon steel quickly forms a protective oxide layer in acidic environments.
● C) Carbon steel corrodes rapidly in acidic environments.
● D) Carbon steel undergoes passivation in acidic environments.
Answer: C) Carbon steel corrodes rapidly in acidic environments.
Explanation: Carbon steel is prone to rapid corrosion in acidic environments because the
protective oxide layer is unstable in acidic conditions.
7. In the context of material selection for corrosion resistance, what is the
significance of the term "galvanic series"?
● A) It ranks materials based on their density.
● B) It ranks materials based on their hardness.
● C) It ranks materials based on their corrosion potential in seawater.
● D) It ranks materials based on their melting point.
Answer: C) It ranks materials based on their corrosion potential in seawater.
Explanation: The galvanic series lists metals and alloys according to their electrochemical
potential in a specific environment, such as seawater, helping to predict galvanic corrosion.
8. Which property of stainless steel makes it more resistant to stress corrosion
cracking compared to carbon steel?
● A) High carbon content
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, Senior Corrosion Technologist
● B) High chromium content
● C) Low thermal conductivity
● D) High ductility
Answer: B) High chromium content
Explanation: The high chromium content in stainless steel enhances its resistance to stress
corrosion cracking by forming a protective oxide layer.
9. What role does molybdenum play in enhancing the corrosion resistance of
stainless steel?
● A) Increases hardness
● B) Improves tensile strength
● C) Enhances resistance to pitting corrosion
● D) Reduces thermal expansion
Answer: C) Enhances resistance to pitting corrosion
Explanation: Molybdenum improves the resistance of stainless steel to pitting corrosion,
particularly in chloride-containing environments.
10. Which metallurgical phenomenon occurs when two different metals are in
electrical contact in a corrosive environment?
● A) Pitting corrosion
● B) Galvanic corrosion
● C) Crevice corrosion
● D) Intergranular corrosion
Answer: B) Galvanic corrosion
Explanation: Galvanic corrosion occurs when two dissimilar metals are electrically
connected in a corrosive environment, leading to accelerated corrosion of the more anodic
material.
11. Which element is added to carbon steel to increase its hardenability?
● A) Sulfur
● B) Phosphorus
● C) Manganese
● D) Silicon
Answer: C) Manganese
Explanation: Manganese is added to carbon steel to increase its hardenability, improve
strength, and help remove oxygen and sulfur impurities during steelmaking.
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, Senior Corrosion Technologist
12. What is the primary reason for the susceptibility of carbon steel to
localized corrosion in chloride environments?
● A) High chromium content
● B) Presence of sulfides
● C) Lack of a passive film
● D) High carbon content
Answer: C) Lack of a passive film
Explanation: Carbon steel does not form a stable passive film in chloride environments,
making it more susceptible to localized corrosion such as pitting and crevice corrosion.
13. What effect does increasing the carbon content in steel have on its
weldability?
● A) Increases weldability
● B) Decreases weldability
● C) Has no effect on weldability
● D) Improves corrosion resistance
Answer: B) Decreases weldability
Explanation: Increasing carbon content in steel decreases its weldability due to the
formation of harder, more brittle microstructures, which can lead to cracking during welding.
14. Which stainless steel grade is most commonly used for food processing
equipment due to its high corrosion resistance and ease of cleaning?
● A) 304
● B) 409
● C) 430
● D) 316
Answer: A) 304
Explanation: Grade 304 stainless steel is widely used in food processing because it offers
good corrosion resistance, is easy to clean, and does not impart any taste to food products.
15. What is the primary characteristic of austenitic stainless steels that
distinguishes them from other types of stainless steel?
● A) Magnetic properties
● B) Ferritic microstructure
● C) High carbon content
● D) Non-magnetic properties
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