Question 1

With thermal fatigue, time to failure is a function of the magnitude of the stress and the number of cycles and decreases with _________ stress and ________ cycles.
A) Increasing, Decreasing
B) Increasing, Increasing
C) Decreasing, Decreasing
D) Decreasing, Increasing

Accepted Answer

Thermal fatigue failure occurs more quickly with higher stress levels and a greater number of cycles.

Question 2

For a specific material, HTHA is dependent on temperature, hydrogen partial pressure, time and _________.
A) Stress
B) Pressure
C) Velocity
D) Alloy composition

Accepted Answer

HTHA (High Temperature Hydrogen Attack) is a type of corrosion that occurs in materials exposed to high temperature and high-pressure hydrogen environments. This corrosion is accelerated by the presence of stress, making option A the correct choice. The other options may also have some influence on HTHA, but stress is a major contributing factor.

Question 3

Corrosion from oxygen tends to be __________ type damage and can show up anywhere even if only very small amounts break through the scavenging system.
A) General
B) Localized
C) Pitting
D) Cracking

Accepted Answer

The answer of Corrosion from oxygen tends to be __________...

Question 4

Carbonate cracking typically propagates _________ to the weld; the pattern of cracking observed on the surface is sometimes described as ________.
A) Transverse, Eyebrow
B) Parallel, Spider web
C) Diagonal, Half moon
D) Perpendicular, Stair step

Accepted Answer

The answer of Carbonate cracking typically propagates _________ to the...

Question 5

Cracks connecting hydrogen blisters are referred to as ________.
A) SOHIC
B) HIC
C) SCC
D) None of the above

Accepted Answer

The answer of Cracks connecting hydrogen blisters are referred to...

Question 6

For some materials such as titanium, carbon steel and low alloy steel, the number of cycles to fatigue fracture decreases with ________ until an endurance limit is reached. Below this endurance limit, fatigue cracking will not occur, regardless of the number of cycles.
A) Temperature increases
B) Stress endurance
C) Pressure decreases
D) None of the above

Accepted Answer

The number of cycles to fatigue fracture decreases with stress endurance until an endurance limit is reached. Below this endurance limit, fatigue cracking will not occur, regardless of the number of cycles. Temperature and pressure can affect the fatigue life of materials, but they do not directly affect the endurance limit.

Question 7

PWHT is ___________ in preventing caustic SCC.
A) Effective
B) Not effective
C) Not practical
D) None of the above

Accepted Answer

PWHT (Post Weld Heat Treatment) is effective in preventing caustic SCC (Stress Corrosion Cracking). This is because PWHT can reduce residual stresses in the weld zone, which are known to promote SCC. Additionally, PWHT can alter the microstructure of the metal, making it less susceptible to SCC. Therefore, PWHT is a commonly used method for preventing caustic SCC in welded components.

Question 8

Which of the following materials is susceptible to sigma phase embrittlement?
A) Carbon steel
B) Low alloy steel
C) 300 Series SS
D) Both A and B

Accepted Answer

300 Series SS is susceptible to sigma phase embrittlement as it has a higher susceptibility to sigma phase formation due to its high chromium and nickel content. Carbon steel and low alloy steel have a lower susceptibility to sigma phase embrittlement.

Question 9

Sulfur and chlorine species in fuel will form sulfur dioxide, sulfur trioxide and hydrogen chloride within the combustion products. At low enough temperatures, these gases and the water vapor in the flue gas will condense to form _________ acid.
A) Hydrochloric
B) Hydrofluoric
C) Sulfuric
D) Both A and C

Accepted Answer

The sulfur species will form sulfur dioxide and sulfur trioxide, which react with water vapor in the flue gas to form sulfuric acid. The chlorine species will form hydrogen chloride, which can also react with water to form hydrochloric acid. Therefore, both hydrochloric acid and sulfuric acid can form in the combustion products.

Question 10

In HF service, carbon steel forms a protective fluoride scale in dry concentrated acid. Loss of the protective scale through high _________ or turbulence will result in greatly accelerated corrosion rates.
A) Temperature
B) Pressure
C) Velocities
D) None of the above

Accepted Answer

Carbon steel can withstand dry concentrated acid due to the formation of a protective fluoride scale on the surface. However, high velocities or turbulence can cause the scale to be removed, exposing the steel to the acid and resulting in accelerated corrosion rates. High temperature or pressure does not directly affect the formation or maintenance of the protective scale, making options A and B incorrect.

Question 11

Wet H₂S services or _________ acid services are process where hydrogen diffuses into the steel and hydrogen embrittlement (HE) is an issue.
A) HF
B) Sulfuric
C) Caustic
D) HCL

Accepted Answer

Wet H₂S services involve hydrogen diffusion into steel, which can lead to hydrogen embrittlement (HE). Hydrogen fluoride (HF) is well known for causing HE in steel and other metals. Therefore, option A is the best choice. Sulfuric acid services can also sometimes cause HE, but it is less common than with HF. Caustic and HCl services do not typically result in HE.

Question 12

A quick test for embrittlement from _________ is a bend test or crush test. Unaffected material will be crushed in a ductile fashion while embrittled components will crack with no signs of ductility.
A) Titanium Hydriding
B) Temper embrittlement
C) Caustic embrittlement
D) None of the above.

Accepted Answer

Titanium Hydriding is a form of embrittlement that can occur in titanium alloys when they are exposed to hydrogen gas. A quick test for embrittlement from titanium hydriding is a bend test or crush test. Unaffected material will be crushed in a ductile fashion while embrittled components will crack with no signs of ductility.

Question 13

Vessels constructed after December, 1987 are subject to the requirements of ________ of ASME Section VIII, Division 1.
A) UW-26
B) UG-31
C) UB-54
D) UCS-66

Accepted Answer

Vessels constructed after December 1987 are subject to the requirements of UCS-66 in ASME Section VIII, Division 1, which deals with the impact testing requirements for materials used in pressure vessels.

Question 14

Dissimilar weld metal cracking occurs because the coefficients of thermal expansion between ferritic steels and 300 Series stainless steels differ by ________ or more.
A) 10%
B) 15%
C) 20%
D) 30%

Accepted Answer

The answer of Dissimilar weld metal cracking occurs because the...

Question 15

Refractory anchors must be resistant to __________ in high temperature services.
A) Thermal fatigue
B) Thermal cracking
C) Stress cracking
D) Oxidation

Accepted Answer

Refractory anchors are used to hold refractory materials in place in high temperature environments. These environments often involve oxidation, which can cause deterioration of the anchors over time. Therefore, it is crucial for refractory anchors to be resistant to oxidation to ensure their longevity and effectiveness. Thermal fatigue and cracking as well as stress cracking are also concerns in high temperature services, but they are not as directly linked to the use of refractory anchors as oxidation.

Question 16

The severity of hydrochloric acid corrosion ________ with _________ HCl concentration and increasing temperatures.
A) Decreases, decreasing
B) Increases, increasing
C) Decreases, increasing
D) Increases, decreasing

Accepted Answer

The severity of hydrochloric acid corrosion increases with increasing HCl concentration and increasing temperatures. This is because higher concentrations of HCl increase the number of acid molecules available to react with the material, and higher temperatures speed up the reaction between the acid and the material.

Question 17

Which of the following materials is affected by high temperature corrosion?
A) Carbon steel
B) 300 Series SS
C) 400 Series SS
D) All of the above

Accepted Answer

All of the above materials are affected by high temperature corrosion.

Question 18

In most cases, brittle fracture occurs only at temperatures below the Charpy impact transition temperature. Steel cleanliness and ________ have a significant influence on toughness and resistance to brittle fracture.
A) Alloy composition
B) Tensile strength
C) Grain size
D) Pressure

Accepted Answer

Grain size affects the toughness of steel; finer grains improve toughness and resistance to brittle fracture.

Question 19

Oxidation of carbon steel begins to become significant above _________.
A) 800º F
B) 900º F
C) 1000º F
D) 1100º F

Accepted Answer

The oxidation of carbon steel becomes significant above 1000º F.

Question 20

Cracking of dissimilar weld metals occurs in the __________ side of a weld joining 300 Series SS and carbon steel.
A) Austenitic
B) Ferritic
C) Both of the above
D) None of the above

Accepted Answer

The cracking of dissimilar weld metals occurs in the ferritic side of a weld joining 300 Series SS and carbon steel. This is due to the difference in thermal expansion coefficients and the formation of brittle intermetallic compounds.

Exam 1: Corrosion and Materials

With thermal fatigue, time to failure is a function of the magnitude of the stress and the number of cycles and decreases with _ stress and cycles.

For a specific material, HTHA is dependent on temperature, hydrogen partial pressure, time and _________.

Corrosion from oxygen tends to be __________ type damage and can show up anywhere even if only very small amounts break through the scavenging system.

Carbonate cracking typically propagates _ to the weld; the pattern of cracking observed on the surface is sometimes described as .

Cracks connecting hydrogen blisters are referred to as ________.

For some materials such as titanium, carbon steel and low alloy steel, the number of cycles to fatigue fracture decreases with ________ until an endurance limit is reached. Below this endurance limit, fatigue cracking will not occur, regardless of the number of cycles.

PWHT is ___________ in preventing caustic SCC.

Which of the following materials is susceptible to sigma phase embrittlement?

Sulfur and chlorine species in fuel will form sulfur dioxide, sulfur trioxide and hydrogen chloride within the combustion products. At low enough temperatures, these gases and the water vapor in the flue gas will condense to form _________ acid.

In HF service, carbon steel forms a protective fluoride scale in dry concentrated acid. Loss of the protective scale through high _________ or turbulence will result in greatly accelerated corrosion rates.

Wet H₂S services or _________ acid services are process where hydrogen diffuses into the steel and hydrogen embrittlement (HE) is an issue.

A quick test for embrittlement from _________ is a bend test or crush test. Unaffected material will be crushed in a ductile fashion while embrittled components will crack with no signs of ductility.

Vessels constructed after December, 1987 are subject to the requirements of ________ of ASME Section VIII, Division 1.

Dissimilar weld metal cracking occurs because the coefficients of thermal expansion between ferritic steels and 300 Series stainless steels differ by ________ or more.

Refractory anchors must be resistant to __________ in high temperature services.

The severity of hydrochloric acid corrosion with _ HCl concentration and increasing temperatures.

Which of the following materials is affected by high temperature corrosion?

In most cases, brittle fracture occurs only at temperatures below the Charpy impact transition temperature. Steel cleanliness and ________ have a significant influence on toughness and resistance to brittle fracture.

Oxidation of carbon steel begins to become significant above _________.

Cracking of dissimilar weld metals occurs in the __________ side of a weld joining 300 Series SS and carbon steel.