Question 1

Foul smelling water may be a sign of fouling and/or _______
A) MIC
B) HIC
C) SOHIC
D) All of the above

Accepted Answer

Foul smelling water may be a sign of microbial-induced corrosion (MIC), which occurs when microorganisms produce acids that corrode metal surfaces. Fouling and SOHIC (stress-oriented hydrogen-induced cracking) may also cause issues with water quality, but foul smelling water is not necessarily a specific indicator of these types of corrosion.

Question 2

Hydrogen stress cracking is the same mechanism that is responsible for sulfide stress corrosion cracking in wet H₂S environments except that HF acid is generating the __________.
A) Sulfide
B) Caustic
C) Hydrogen
D) Water

Accepted Answer

Hydrogen stress cracking occurs when atomic hydrogen is present in a metal and becomes absorbed into the metal's microstructure. This can occur during the corrosion process, specifically in the presence of hydrogen-containing fluids such as water or acids like hydrofluoric acid (HF). Once absorbed, the hydrogen atoms can cause the metal to become brittle and eventually crack, leading to failure. Therefore, the correct answer is C, hydrogen is generating the stress cracking, not sulfide or caustic.

Question 3

Geometry, stress level, _________ and material properties are the predominate factors in determining the fatigue resistance of a component.
A) Temperature
B) Pressure
C) Velocity
D) Number of cycles

Accepted Answer

The number of cycles, also known as the fatigue life, is a crucial factor in determining the fatigue resistance of a component. The other choices, temperature, pressure, and velocity, can affect a component's performance but are not the primary factors in fatigue resistance. Material properties, such as strength and toughness, also play a significant role in the fatigue life of a component.

Question 4

Alloy 400 is susceptible to LME when it comes in contact with molten ________.
A) Cadmium
B) Mercury
C) Zinc
D) Lead

Accepted Answer

Alloy 400 is susceptible to liquid metal embrittlement (LME) when it comes in contact with molten mercury. The other options (A) Cadmium, (C) Zinc, and (D) Lead are not known to cause LME in Alloy 400.

Question 5

Amine units are used in refineries to remove H₂S, CO₂ and _________ from process streams originating in many units including the coker, crude, FCC and hydrogen.
A) NA₂
B) Cl₂
C) Mercaptans
D) None of the above

Accepted Answer

Amine units are used to remove H₂S and CO₂ in refineries, but mercaptans are also commonly removed through this process. Mercaptans are sulfur compounds that can cause corrosion and foul odors, so it is important to remove them from process streams. Therefore, option C is the correct choice. Options A and B are not correct because they do not match the compounds typically removed by amine units, and option D is too broad and open-ended to be correct.

Question 6

At high temperatures, metal components can slowly and continuously deform under load below the yield stress. This time dependent deformation of stressed components is known as __________.
A) Deformation
B) Fatigue
C) Creep
D) Thermal fatigue

Accepted Answer

The time-dependent deformation of stressed components at high temperatures is known as creep. This is a common issue in high-temperature applications and can lead to failure over time. Deformation, fatigue, and thermal fatigue may also occur, but they refer to different types of failure mechanisms.

Question 7

Thermal fatigue damage is in the form of cracking that may occur anywhere in a metallic component where relative movement is constrained, particularly under repeated __________.
A) Cyclic stresses
B) Thermal cycling
C) Pressure variations
D) All of the above

Accepted Answer

Thermal fatigue damage is primarily caused by thermal cycling, which involves repeated heating and cooling, leading to expansion and contraction that can cause cracking in constrained components.

Question 8

Soil corrosion appears as external thinning with localized losses due to _________.
A) Resistivity
B) Pitting
C) General corrosion
D) Potential

Accepted Answer

Soil corrosion often results in pitting, where localized areas of metal surface are eroded at a faster rate than the surrounding areas. This can lead to the formation of small holes or pits on the surface of the metal, which can eventually weaken the structure and lead to failure. This type of corrosion is particularly common in soils that are acidic or contain high levels of moisture, as these conditions can accelerate the corrosion process. Resistivity, potential, and general corrosion can also contribute to soil corrosion, but are not typically associated with pitting.

Question 9

Which of the following materials is susceptible to carburization?
A) Low alloy steels
B) 300 Series SS
C) 400 Series SS
D) All of the above

Accepted Answer

All of the above materials can be susceptible to carburization under certain conditions. Carburization is the process of adding carbon to the surface of a material, and it can occur when the material is in contact with a carbon-rich atmosphere at high temperatures. Low alloy steels, 300 Series SS, and 400 Series SS can all be exposed to carbon-rich atmospheres in various industrial applications, so they all have the potential to undergo carburization.

Question 10

Sulfidation is also known as ____________.
A) Sulfur corrosion
B) Sulfate corrosion
C) Sulfidic corrosion
D) None of the above

Accepted Answer

Sulfidation refers to the process of corrosion caused by the reaction between metal surfaces and hydrogen sulfide or sulfur compounds in industrial environments. It results in the formation of metal sulfides and can lead to structural damage and failure of the affected component. Sulfur corrosion (A) is not a commonly recognized term, and sulfate corrosion (B) refers to a different type of corrosion caused by the reaction between metal surfaces and sulfate compounds in aqueous environments.

Question 11

SCC generally occurs below about _______.
A) 150º F
B) 180º F
C) 210º F
D) 240º F

Accepted Answer

SCC generally occurs below about 180º F (82º C).

Question 12

Titanium Hydriding damage occurs primarily in sour water strippers and amine units in the overhead condensers, heat exchanger tubes and other titanium equipment operating above _________.
A) 300º F
B) 270º F
C) 210º F
D) 165º F

Accepted Answer

The answer of Titanium Hydriding damage occurs primarily in sour...

Question 13

Corrosion by HF (Hydrofluoric) acid can result in high rates of general or localized corrosion and may be accompanied by hydrogen cracking, blistering and ________.
A) HIC
B) Delayed cracking
C) SOHIC
D) Both A and C

Accepted Answer

HF acid corrosion can result in hydrogen-induced cracking (HIC) and stress-oriented hydrogen-induced cracking (SOHIC) as well as other forms of cracking such as delayed cracking. Therefore, both option A and C are correct, making option D the best choice.

Question 14

_________ is a selective corrosion mechanism in which one or more constituents of an alloy are preferentially attacked leaving a lower density often porous structure.
A) Phenol corrosion
B) Dealloying
C) Carburization
D) Preferentially weld attack

Accepted Answer

This mechanism is commonly known as dealloying, also referred to as selective leaching or parting corrosion. It occurs when one or more less noble elements are preferentially removed from the alloy, leaving behind a more noble, porous structure. This can result in a decrease in strength and mechanical properties of the material.

Question 15

Areas of vulnerability in sulfuric acid Alkylation units include reactor effluent lines, reboilers, deisobutanizer, overhead systems and the _________ treating system.
A) Caustic
B) Sulfuric acid
C) Catalyst
D) H₂S

Accepted Answer

The areas of vulnerability listed are all related to the sulfuric acid alkylation process, which involves the use of highly reactive chemicals that can cause corrosion and damage to equipment. The caustic treating system is another area of vulnerability because it is responsible for neutralizing any residual acid that may be present in the effluent produced by the process. Failure of this system could lead to the release of acid into the environment, which could be catastrophic for both humans and the environment. Therefore, the caustic treating system is a critical component that must be carefully monitored and maintained to ensure the safe and effective operation of the alkylation unit.

Question 16

A form of corrosion that can occur at the junction of dissimilar metals when they are joined together in a suitable electrolyte is __________.
A) Galvanic corrosion
B) Anodic corrosion
C) Cathodic corrosion
D) All of the above

Accepted Answer

Galvanic corrosion occurs when two dissimilar metals are in contact with each other in the presence of an electrolyte, causing one of the metals to be corroded while the other remains protected. Anodic corrosion and cathodic corrosion are both types of galvanic corrosion and can occur as separate processes within it. However, neither of these options fully captures the phenomenon in question.

Question 17

Sigma phase occurs in Ferritic, martensitic, austenitic and duplex stainless steels when exposed to temperatures in the range of _____.
A) 537º C - 954º C
B) 621º C - 926º C
C) 676º C - 760º C
D) 584º C - 840º C

Accepted Answer

Sigma phase formation in stainless steels typically occurs within the temperature range of 537º C to 954º C.

Question 18

____________ is often found in piping and equipment that handles caustic, including H₂S and mercaptan removal units, as well as equipment that uses caustic for neutralization in sulfuric acid and HF acid units.
A) Carburization
B) Sulfide corrosion
C) Caustic embrittlement
D) Hydrogen cracking

Accepted Answer

Caustic embrittlement is a type of corrosion caused by the exposure of metals to concentrated caustic, which can lead to cracking and eventual failure of the affected equipment. It is commonly found in equipment that handles caustic for various industrial processes, including those mentioned in the question. Carburization, sulfide corrosion, and hydrogen cracking are all different types of corrosion but are not directly related to the use of caustic.

Question 19

Caustic is sometimes added to process streams for ________ or as a reactant.
A) Stability
B) Corrosion control
C) Neutralization
D) Inhibiting

Accepted Answer

The answer of Caustic is sometimes added to process streams...

Question 20

Which of the following materials are subject to mechanical fatigue?
A) Carbon steels
B) Stainless steels
C) Low alloy steels
D) All of the above

Accepted Answer

All three types of steels (carbon steels, stainless steels, and low alloy steels) are subject to mechanical fatigue. Fatigue occurs when a material is subjected to repeated loading and unloading cycles, which can lead to cracking and failure over time. Therefore, all of the given choices are subject to mechanical fatigue.

Exam 1: Corrosion and Materials

Foul smelling water may be a sign of fouling and/or _______

Hydrogen stress cracking is the same mechanism that is responsible for sulfide stress corrosion cracking in wet H₂S environments except that HF acid is generating the __________.

Geometry, stress level, _________ and material properties are the predominate factors in determining the fatigue resistance of a component.

Alloy 400 is susceptible to LME when it comes in contact with molten ________.

Amine units are used in refineries to remove H₂S, CO₂ and _________ from process streams originating in many units including the coker, crude, FCC and hydrogen.

At high temperatures, metal components can slowly and continuously deform under load below the yield stress. This time dependent deformation of stressed components is known as __________.

Thermal fatigue damage is in the form of cracking that may occur anywhere in a metallic component where relative movement is constrained, particularly under repeated __________.

Soil corrosion appears as external thinning with localized losses due to _________.

Which of the following materials is susceptible to carburization?

Sulfidation is also known as ____________.

SCC generally occurs below about _______.

Titanium Hydriding damage occurs primarily in sour water strippers and amine units in the overhead condensers, heat exchanger tubes and other titanium equipment operating above _________.

Corrosion by HF (Hydrofluoric) acid can result in high rates of general or localized corrosion and may be accompanied by hydrogen cracking, blistering and ________.

_________ is a selective corrosion mechanism in which one or more constituents of an alloy are preferentially attacked leaving a lower density often porous structure.

Areas of vulnerability in sulfuric acid Alkylation units include reactor effluent lines, reboilers, deisobutanizer, overhead systems and the _________ treating system.

A form of corrosion that can occur at the junction of dissimilar metals when they are joined together in a suitable electrolyte is __________.

Sigma phase occurs in Ferritic, martensitic, austenitic and duplex stainless steels when exposed to temperatures in the range of _____.

____________ is often found in piping and equipment that handles caustic, including H₂S and mercaptan removal units, as well as equipment that uses caustic for neutralization in sulfuric acid and HF acid units.

Caustic is sometimes added to process streams for ________ or as a reactant.

Which of the following materials are subject to mechanical fatigue?