Question 1

With 885º F embrittlement, increasing amounts of ________ increase susceptibility to damage when operating in the high temperature range of concern.
A) Chromium
B) Hardness
C) Ferrite
D) Hydrogen

Accepted Answer

Ferrite is known to increase susceptibility to 885º F embrittlement, which is a concern in certain stainless steels when operating at high temperatures.

Question 2

The creep threshold temperature for carbon steel is ________.
A) 315º C
B) 371º C
C) 426º C
D) 538º C

Accepted Answer

The creep threshold temperature for carbon steel is typically around 371º C, above which creep deformation becomes significant.

Question 3

Contrary to a pure mechanical fatigue, there is no _________ load in corrosion-assistant fatigue. Corrosion promotes failure at a lower stress and number of cycles than the materials normal endurance.
A) Tensile
B) Stress
C) Ductile
D) Fatigue limit

Accepted Answer

In corrosion-assisted fatigue, the presence of a corrosive environment reduces the fatigue limit, meaning that failure can occur at lower stress levels and fewer cycles compared to the material's normal endurance without corrosion.

Question 4

SCC usually occurs at pH values above two (2). SCC tendency __________ toward the alkaline pH region
A) Increases
B) Decreases
C) Stabilizes
D) None of the above

Accepted Answer

Stress Corrosion Cracking (SCC) tendency generally decreases as the environment becomes more alkaline, moving away from acidic conditions.

Question 5

Refractory anchor material must be compatible with the _________ of the base metal
A) Composition
B) Welding
C) Thermal coefficient
D) Ductility

Accepted Answer

The answer of Refractory anchor material must be compatible with...

Question 6

_________ material sections also have a ___________ resistance to brittle fracture due to higher constraint, which increases triaxial stresses at the crack tip.
A) Thinner, Lower
B) Thicker, Lower
C) Thinner, Higher
D) Thicker, Higher

Accepted Answer

The answer of _________ material sections also have a ___________...

Question 7

A form of fatigue cracking in which cracks develop under the combined effects of cyclic loading and corrosion is called _______. Cracking often initiates at stress concentrations such as a pit in the surface.
A) Cyclic cracking
B) Corrosion fatigue
C) Stress fatigue
D) Stress cracking

Accepted Answer

Corrosion fatigue is a form of fatigue cracking that occurs due to the combined effects of cyclic loading and corrosion. Cracks often initiate at stress concentrations such as a pit in the surface.

Question 8

The creep threshold temperature for 1 ¼, 2 ¼, 5 and 9 Cr is ________.
A) 600º F
B) 700º F
C) 800º F
D) 1000º F

Accepted Answer

The creep threshold temperature for 1 ¼, 2 ¼, 5 and 9 Cr is commonly accepted to be 800º F.

Question 9

___________ cracking has been a major problem in coke drum shells.
A) Stress
B) Carburization
C) Thermal fatigue
D) Sulfide

Accepted Answer

Thermal fatigue cracking has been a major problem in coke drum shells due to the cyclic heating and cooling during the coking process. This can lead to thermal stresses that cause cracking. Stress cracking can also occur, but it is typically less of an issue than thermal fatigue cracking. Carburization and sulfide cracking are not common issues in coke drum shells.

Question 10

Temper embrittlement is a metallurgical change that is not readily apparent and can be confirmed through ________.
A) Metallographic examination
B) Impact testing
C) Metallography
D) None of the above

Accepted Answer

Impact testing is used to confirm temper embrittlement as it measures the material's toughness and ability to absorb energy during fracture, which is affected by embrittlement.

Question 11

Stresses acting on the weldments are significantly ________ when austenitic stainless steel filler metal is used. A nickel based filler metal has a coefficient of thermal expansion closer to carbon steel resulting in significantly lower stress at elevated temperatures.
A) Lower
B) Higher
C) Altered
D) None of the above

Accepted Answer

Austenitic stainless steel filler metals have a higher coefficient of thermal expansion compared to carbon steel, leading to higher stresses in the weldments.

Question 12

Damage due to __________ is not visible and can only be observed by metallographic examination.
A) Galvanic corrosion
B) Brittle fracture
C) Cavitation
D) Graphitization

Accepted Answer

Graphitization is a metallurgical phenomenon that occurs when carbon steel is exposed to high temperatures over a long period of time. The carbon in the steel migrates to the surface and forms graphite, resulting in a loss of strength and ductility. This process is not visible and can only be detected through metallographic examination.

Question 13

In most cases, brittle fracture occurs only at temperatures _________ the Charpy impact transition temperature.
A) Above
B) Below
C) Around
D) Inside

Accepted Answer

Brittle fracture occurs below the Charpy impact transition temperature. At temperatures above the transition temperature, materials become ductile and able to absorb more energy before fracturing, which makes them less likely to experience brittle fracture.

Question 14

Key factors affecting thermal fatigue are the magnitude of the temperature and the __________.
A) Number of cycles
B) Pressure
C) Stress
D) Alloy composition

Accepted Answer

The number of cycles is the other major factor affecting thermal fatigue along with the temperature magnitude. However, the question asks for the best choice, which is only A. Pressure, stress, and alloy composition may have an impact on other types of fatigue, but not specifically on thermal fatigue.

Question 15

Creep and stress rupture is more likely in a _________ grained material than a _______ grained material.
A) Course, Fine
B) Fine, Course
C) Austenitic, Martensitic
D) None of the above

Accepted Answer

The answer of Creep and stress rupture is more likely...

Question 16

In susceptible materials, the primary factor that affects sigma phase formation is the ________ at elevated temperatures.
A) Time of exposure
B) Pressure
C) Stress
D) Velocity

Accepted Answer

The time of exposure at elevated temperatures is the primary factor that affects sigma phase formation in susceptible materials.

Question 17

Steel cleanliness and _______ have a significant influence on toughness and resistance to brittle fracture.
A) Composition
B) Alloy
C) Grain size
D) None of the above

Accepted Answer

Grain size significantly influences the toughness and resistance to brittle fracture in steel, as smaller grains can impede crack propagation and improve toughness.

Question 18

A form of thermal cracking, __________, can occur when high and nonuniform thermal stresses develop over a relatively short period of time in a piece of equipment due to differential expansion and contraction.
A) Thermal expansion
B) Thermal stress
C) Thermal shock
D) Linear expansion

Accepted Answer

Thermal shock occurs when there is a sudden and large difference in temperature which causes rapid expansion or contraction of a material. This can lead to cracking due to the nonuniform and high thermal stresses that are generated.

Question 19

The rate of creep deformation is a function of the material, load and temperature. The rate of damage is sensitive to both load and temperature. Generally, an increase of about _______ or an increase of ________ on stress can cut the remaining life in half.
A) 25º F, 15%
B) 50º F, 10%
C) 50º F, 15%
D) 25º F, 10%

Accepted Answer

The answer of The rate of creep deformation is a...

Question 20

Sigma phase in welds can be minimized by controlling ferrite in the range of _________ for Type 347 SS.
A) 3%-5%
B) 5%-7%
C) 7%-9%
D) 5%-9%

Accepted Answer

The answer of Sigma phase in welds can be minimized...

Exam 1: Corrosion and Materials

With 885º F embrittlement, increasing amounts of ________ increase susceptibility to damage when operating in the high temperature range of concern.

The creep threshold temperature for carbon steel is ________.

Contrary to a pure mechanical fatigue, there is no _________ load in corrosion-assistant fatigue. Corrosion promotes failure at a lower stress and number of cycles than the materials normal endurance.

SCC usually occurs at pH values above two (2) . SCC tendency __________ toward the alkaline pH region

Refractory anchor material must be compatible with the _________ of the base metal

_ material sections also have a ___ resistance to brittle fracture due to higher constraint, which increases triaxial stresses at the crack tip.

A form of fatigue cracking in which cracks develop under the combined effects of cyclic loading and corrosion is called _______. Cracking often initiates at stress concentrations such as a pit in the surface.

The creep threshold temperature for 1 ¼, 2 ¼, 5 and 9 Cr is ________.

___________ cracking has been a major problem in coke drum shells.

Temper embrittlement is a metallurgical change that is not readily apparent and can be confirmed through ________.

Stresses acting on the weldments are significantly ________ when austenitic stainless steel filler metal is used. A nickel based filler metal has a coefficient of thermal expansion closer to carbon steel resulting in significantly lower stress at elevated temperatures.

Damage due to __________ is not visible and can only be observed by metallographic examination.

In most cases, brittle fracture occurs only at temperatures _________ the Charpy impact transition temperature.

Key factors affecting thermal fatigue are the magnitude of the temperature and the __________.

Creep and stress rupture is more likely in a ___ grained material than a _ grained material.

In susceptible materials, the primary factor that affects sigma phase formation is the ________ at elevated temperatures.

Steel cleanliness and _______ have a significant influence on toughness and resistance to brittle fracture.

A form of thermal cracking, __________, can occur when high and nonuniform thermal stresses develop over a relatively short period of time in a piece of equipment due to differential expansion and contraction.

The rate of creep deformation is a function of the material, load and temperature. The rate of damage is sensitive to both load and temperature. Generally, an increase of about _ or an increase of __ on stress can cut the remaining life in half.

Sigma phase in welds can be minimized by controlling ferrite in the range of _________ for Type 347 SS.