Question 1

A prime location for erosion is:
A) In catalyst piping.
B) Downstream of a gate valve.
C) Any superheated steam piping.
D) Upstream of a pump.

Accepted Answer

The answer of A prime location for erosion is:
A) In...

Question 2

Thermal fatigue cracks usually:
A) Initiate on the surface of the component.
B) Initiate in the subsurface of the component.
C) Grow very rapidly (at the speed of sound in the material).
D) Are very tight and narrow.

Accepted Answer

Thermal fatigue cracks typically initiate on the surface of the component due to the cyclic thermal stresses that occur at the surface.

Question 3

Atmospheric corrosion is of greatest concern in:
A) Dry climates in rural locations.
B) Dry climates in industrial locations.
C) Wet climates in rural locations.
D) Wet climates in industrial locations.

Accepted Answer

Wet climates, particularly those in industrial locations, are the most conducive to atmospheric corrosion. Industrial areas often have higher levels of pollution and contaminants in the air, which can accelerate the corrosion process. Additionally, the presence of moisture in the air can increase the rate of corrosion. Therefore, wet industrial locations are particularly concerning for atmospheric corrosion.

Question 4

Which of the following is not a primary initiating point for thermal fatigue?
A) Notches
B) Rounded pits
C) Nozzle-to-shell welds
D) Weld toes

Accepted Answer

Rounded pits are not a primary initiating point for thermal fatigue. Notches, nozzle-to-shell welds, and weld toes are common initiating points for thermal fatigue due to the stress concentrations they create.

Question 5

Which of the following does not increases the likelihood of atmospheric corrosion?
A) Bird poop
B) Increasing annual rainfalls
C) Locations where moisture is trapped
D) Increasing operating pressures
E) Increasing amounts of airborne contaminates

Accepted Answer

Operating pressures do not have a direct effect on atmospheric corrosion. Corrosion in pipelines usually occurs due to the presence of water, oxygen, and contaminants in the atmosphere. Factors such as moisture, contaminants, and locations where moisture is trapped increase the likelihood of atmospheric corrosion. Bird poop and increasing annual rainfall can also contribute to atmospheric corrosion as they contain acidic substances that can corrode metal surfaces.

Question 6

Which of the following is not a prime candidate for thermal fatigue?
A) Coke drums
B) Steam actuated soot blowers
C) Mix points of hot and cold streams
D) 600 psig steam piping
E) Welds joining materials having different coefficients of expansion

Accepted Answer

Thermal fatigue occurs due to cyclic heating and cooling of a material, which causes it to expand and contract. 600 psig steam piping is designed to withstand high pressure and temperature, so it would not be prone to thermal fatigue. However, A, B, C, and E are all potential candidates for thermal fatigue due to their exposure to cyclic heating and cooling.

Question 7

Which of the following is not a primary factor contributing to erosion-corrosion?
A) Impact angle (angle that impacting particles strike metal)
B) Tensile strength of the metal
C) Velocity of impacting particles
D) Corrosiveness of the environment

Accepted Answer

Tensile strength of the metal is not a primary factor contributing to erosion-corrosion. The primary factors include impact angle, velocity of the impacting particles, and corrosiveness of the environment.

Question 8

Atmospheric corrosion:
A) Can cause either uniform or localized wall loss.
B) Always causes localized wall loss.
C) Always causes uniform wall loss.
D) Is best detected using profile RT.

Accepted Answer

Atmospheric corrosion can cause both uniform and localized wall loss depending on the environment and exposure conditions. It cannot always cause uniform or localized wall loss. Profile RT is a method of examining the steel surface to detect surface defects or irregularities, but it is not necessarily the best method for detecting atmospheric corrosion.

Question 9

The endurance limit is usually about:
A) 10-20% of a material's ultimate tensile strength.
B) 40-50% of a material's ultimate tensile strength
C) 10-20% of a material's yield strength.
D) 40-50% of a material's yield strength.
E) Half way up the ladder of a 150' column (tower).

Accepted Answer

The endurance limit is typically around 40-50% of a material's ultimate tensile strength for ferrous materials.

Question 10

SIMULATION Ways to prevent thermal fatigue include reducing stress concentrators by making _______________ transitions at places where the wall thickness changes.

Accepted Answer

The answer of SIMULATION Ways to prevent thermal fatigue include...

Question 11

The removal of surface material by impacting materials is called:
A) Erosion
B) Erosion corrosion
C) Erosion or erosion corrosion
D) IPC (imparting particle corrosion)

Accepted Answer

The removal of surface material by impacting materials is known as erosion. It is a physical process that involves the wearing away of a surface due to the effect of flowing liquids, such as wind or water, as well as the impact of solid particles.

Question 12

Fatigue will not occur in carbon steel if stresses are below the:
A) Transition limit.
B) Endurance limit.
C) Hardening limit.
D) Speed limit.

Accepted Answer

The endurance limit, also known as the fatigue limit, is the maximum stress level that a material can withstand for an infinite number of cycles without experiencing fatigue failure. In carbon steel, if the stresses are kept below the endurance limit, fatigue failure will not occur. The other options (A, C, and D) do not relate to fatigue limits in materials.

Question 13

Mechanical fatigue is caused by:
A) Cyclic stresses occurring over a long period of time.
B) Higher than average stresses at high temperatures.
C) Constant stresses occurring at low temperatures.
D) Cyclic operating conditions of bird poop then rain, bird poop then rain, etc.

Accepted Answer

Mechanical fatigue is caused by cyclic stresses occurring over a long period of time, causing damage to the material. Options B and C mention specific conditions of high or low temperatures, but they do not necessarily imply cyclic stresses. Option D is not a scientifically valid cause for mechanical fatigue.

Question 14

The best way to prevent failures by atmospheric corrosion is to:
A) Have an aggressive inspection program.
B) Reduce airborne particulates.
C) Install and maintain appropriate coatings.
D) Shoot all birds that cross the plant fence.
E) Build new petrochemical facilities in a dry desert.

Accepted Answer

Installing and maintaining appropriate coatings is the most effective way to prevent failures from atmospheric corrosion. Coatings act as a barrier between the metal surface and the corrosive environment, preventing the metal from being exposed to the corrosive agents in the atmosphere. Regular maintenance of coatings is important to ensure their effectiveness over time. While inspection programs and reducing airborne particulates can also help mitigate corrosion, they are not as effective as using appropriate coatings. Shooting birds and building facilities in dry deserts are not practical or ethical solutions.

Question 15

Which of the following materials are affected by mechanical fatigue cracking?
A) Only carbon steel
B) Only carbon steel and chromes
C) Only carbon steel, and high nickel alloys
D) All materials

Accepted Answer

The answer of Which of the following materials are affected...

Question 16

Which of the following materials is least affected by atmospheric corrosion?
A) Carbon steel
B) Chromes
C) Stainless steels
D) Copper alloyed with aluminum

Accepted Answer

Stainless steels are least affected by atmospheric corrosion due to their high level of chromium and nickel content, which creates a protective layer on the surface of the material. Carbon steel and copper alloyed with aluminum are prone to oxidation and rusting, while chromes may experience pitting and etching under corrosive conditions.

Question 17

Which material does not have an endurance limit?
A) Non-normalized carbon steel
B) Normalized carbon steel
C) Stainless steel
D) Titanium

Accepted Answer

Stainless steel does not have a true endurance limit, meaning it can eventually fail under cyclic loading regardless of the stress level.

Question 18

Many thermal fatigue cracks are filled with:
A) chlorides.
B) hydroslime.
C) oxides.
D) sulfides.

Accepted Answer

Thermal fatigue cracks are often filled with oxides due to the thermal cycling causing expansion and contraction of the material, leading to the formation and propagation of cracks. These cracks can then be filled with oxides from the surrounding environment. Chlorides, hydroslime, and sulfides are not typically associated with thermal fatigue cracks.

Question 19

The removal of a material's protective scale by impacting materials is called:
A) Erosion
B) Erosion-corrosion
C) Erosion or erosion-corrosion
D) IPRSC (imparting particle removal of scale corrosion)

Accepted Answer

The answer of The removal of a material's protective scale...

Question 20

Which of the following is not a primary factor contributing to erosion?
A) Impact angle (angle that impacting particles strike metal)
B) Size of impacting particles
C) Velocity of impacting particles
D) Density of impacting particles
E) Corrosiveness of the environment

Accepted Answer

Corrosiveness of the environment is related to chemical reactions rather than the physical process of erosion, which is primarily influenced by impact angle, size, velocity, and density of particles.

Exam 1: Corrosion and Materials

A prime location for erosion is:

Thermal fatigue cracks usually:

Atmospheric corrosion is of greatest concern in:

Which of the following is not a primary initiating point for thermal fatigue?

Which of the following does not increases the likelihood of atmospheric corrosion?

Which of the following is not a prime candidate for thermal fatigue?

Which of the following is not a primary factor contributing to erosion-corrosion?

Atmospheric corrosion:

The endurance limit is usually about:

SIMULATION Ways to prevent thermal fatigue include reducing stress concentrators by making _______________ transitions at places where the wall thickness changes.

The removal of surface material by impacting materials is called:

Fatigue will not occur in carbon steel if stresses are below the:

Mechanical fatigue is caused by:

The best way to prevent failures by atmospheric corrosion is to:

Which of the following materials are affected by mechanical fatigue cracking?

Which of the following materials is least affected by atmospheric corrosion?

Which material does not have an endurance limit?

Many thermal fatigue cracks are filled with:

The removal of a material's protective scale by impacting materials is called:

Which of the following is not a primary factor contributing to erosion?