API RP 571 MCQ Practice - API-653 Multiple Choice Questions

API RP 571 (Damage Mechanisms Affecting Fixed Equipment in the Refining Industry)

Terms and Definitions – 12 MCQ

API 571 (Terms and Definitions)

The 300 series SS, which commonly include Types 304, 304L, 304H, 309, 310, 316, 316L, 316H, 317, 317L, 321, 321H, 347, and 347H. The “L” and “H” suffixes refer to controlled ranges of low and high carbon content, respectively is referred to as

Austenitic stainless steels

Carbon steels

Duplex stainless steel

Ferritic stainless steel

None

A family of stainless steels that contain a mixed austenitic-ferritic structure including Alloys 2205, 2304, and 2507 is referred to as

Austenitic stainless steels

Duplex stainless steels

Carbon steels

Ferritic stainless steel

None

A family of stainless steels including Types 405, 409, 410S, 430, 442, and 446 is referred to as

Austenitic stainless steels

Duplex stainless steels

Carbon steels

Ferritic stainless steels

None

A family of carbon steels in which higher strength levels are achieved by the addition of moderate amounts of alloying elements such as titanium, vanadium, or niobium in amounts of less than 0.1 % is referred to as

High Strength Low Alloy steel

Low alloy steel

Martensitic stainless steel

None

A family of steels containing up to 9 % chromium and other alloying additions for high temperature strength and creep resistance is referred to as

High Strength Low Alloy steel

Low Alloy steel

None

A family of stainless steels including Types 410, 416, 420, 440A, 440B, and 440C is referred to as

Ferritic stainless steels

Nickle based alloys

Stainless steel

Martensitic stainless steel

None

A family of alloys containing nickel as a major alloying element (>30 % Ni) including Alloys 200, 400, K-500, 800, 800H, 825, 600, 600H, 617, 625, 718, X-750, and C276 is referred to as

Nickel-based

Stainless steel

Carbon steel

Duplex stainless steel

None

An alloy of iron (Fe) with at least 10.5 % chromium (Cr) plus other alloy additions, depending on the specific grade is referred to as

Carbon steel

Ferritic steels

Nickle based alloys

Stainless steel

None

Abbreviation SEM stands for

Scanning Electron Microscope

Steel Electron Microscope

Surface Electron Microscope

Silicon Electron Microscope

None

10.

Abbreviation AUTB stands for

Alternating Ultrasonic Backscatter Testing

Aluminium Ultrasonic Backscatter Testing

Automated Ultrasonic Backscatter Testing

Acoustic Ultrasonic Backscatter Testing

None

11.

Abbreviation AET stands for

Acoustic Emission Testing

Aluminium Emission Testing

Acid Emission Testing

Alkaline Emission Testing

None

12.

Abbreviation ACFM stands for

Acoustic Current Field Measurement

Automated Current Field Measurement

Alternating Current Field Measurement

None of the above are correct

None

1 out of 3

Time's up

Atmospheric Corrosion – 17 MCQ

API 571 (Atmospheric Corrosion)

Which of the following will have most severe atmospheric corrosion?

Marine environments and moist, polluted industrial environments

Wet rural areas

Dry rural areas

All of the above

None

How atmospheric corrosion occurs?

Corrosion that occurs from moisture associated with product inside the tank

Corrosion that occurs from moisture associated with foundation soil

Corrosion that occurs from moisture associated with Insulation

Corrosion that occurs from moisture associated with atmospheric conditions.

None

What are the materials affected by atmospheric corrosion

Carbon steel

Low-alloy steels

Copper alloyed aluminum

All of the above

None

The corrosion rate of marine environment will be

Less than 1 mpy (mill per year)

10 mpy (mill per year)

20 mpy (mill per year)

25 mpy (mill per year)

None

The corrosion rate of industrial environments that contain acids or sulfur compounds that can form acids is about

about 5 mpy to 10 mpy

about 10 mpy to 15 mpy

about 2 mpy to 5 mpy

about 15 mpy to 12 mpy

None

The corrosion rate of Inland locations exposed to a moderate amount of precipitation or humidity are considered moderately corrosive environments will be

about 1 mpy to 10 mpy

about 1 mpy to 3 mpy

about 5 mpy to 10 mpy

about 10 mpy to 13 mpy

None

The corrosion rate of Dry rural environments usually have very low corrosion rates

>1 mpy

<1 mpy

<2 mpy

>2 mpy

None

For atmospheric Corrosion, corrosion rates increase with temperature up to about ___________ °F and above this temperature surfaces are usually too dry for corrosion to occur except under insulation.

350 °F

200 °F

150 °F

250 °F

None

What are the critical factors for an atmospheric corrosion

The physical location of the plant (industrial, marine, urban, rural)

The amount of moisture (humidity, rainfall) typically present or the presence of cooling tower mist

The presence of salts, sulfur compounds, dirt, or other contaminants in the air

All of the above

None

10.

As mentioned the critical factors in an above/previous question, which one of the following is not an additional critical factor for an atmospheric corrosion

Corrosion rates increase with temperature up to about 250 °F (120 °C). Above 250 °F (120 °C), surfaces are usually too dry for corrosion to occur except under insulation

Dry rural environments usually have very low corrosion rates (>5 mpy).

Marine environments can be very corrosive (about 20 mpy) as are industrial environments that contain acids or sulfur compounds that can form acids (about 5 mpy to 10 mpy)

Inland locations exposed to a moderate amount of precipitation or humidity are considered moderately corrosive environments (about 1 mpy to 3 mpy) and Dry rural environments usually have very low corrosion rates (<1 mpy)

None

11.

All of the following are the affected units or equipment from atmospheric corrosion except

Equipment may be susceptible if cycled between ambient and higher or lower operating temperatures.

Equipment upwind of cooling towers and dry gas scrubbers.

Unpainted, uninsulated carbon steel and low-alloy steel piping and equipment operating below 250 °F (120 °C) where moisture can contact the surface

Equipment downwind of cooling towers and wet gas scrubbers.

None

12.

The best prevention method for atmospheric corrosion is

Surface preparation and proper coating application

Cathodic protection and proper coating application

Cathodic protection and Surface preparation

Change in atmospheric conditions

None

13.

The appearance or morphology of damage for an atmospheric corrosion will be all of the following except

If there is no coating, corrosion or loss in thickness can be more general and widespread

If there is proper coating, corrosion or loss in thickness can be more general and widespread

Localized coating failures will promote localized corrosion

The attack will be general or localized, depending upon the condition of the coating, if any, and whether or not the moisture is trapped

None

14.

Atmospheric corrosion

Can cause either uniform or localized wall loss

Always causes localized wall loss

Always causes uniform wall loss

Can be best detected by RT

None

15.

Corrosion rates increase with temperature up to about 250 °F (120 °C). Above 250 °F (120 °C), surfaces are usually ________ for corrosion to occur except under insulation

Too wet

Too dry

Too moist

Too bad

None

16.

Corrosion that occurs from moisture associated with atmospheric conditions. Marine environments and moist, polluted industrial environments with airborne contaminants are the most severe. Dry rural environments cause very little corrosion

Atmospheric corrosion

Galvanic corrosion

Soil corrosion

Cooling water corrosion

None

17.

How an atmospheric corrosion can be inspected and monitored

UT can include techniques like straight beam or angle beam (SWUT or PAUT) to directly measure remaining wall thickness or screening techniques using EMAT or GWT

ECT may include a screening technique such as pulsed eddy current (PEC).

VT includes direct/line-of-sight and indirect methods using a camera, mirror, laser scanning, and/or structured white light imaging with pit gages.

All of the above

None

1 out of 4

Time's up

Brittle Fracture – 18 MCQ

API 571 (Brittle Fracture)

The sudden rapid fracture under stress without plastic deformation is called

Temper embrittlement

Fatigue cracks

Brittle fracture

Ductile fracture

None

Which of the following materials are not affected by brittle fracture

Carbon steel

Austenitic stainless steel

Low alloy steel

400 series SS

None

Which of the following will increase the susceptibility of brittle fracture?

Steel cleanliness

Thick material

Operating temperature below transition temperature

All of the above

None

Brittle fracture normally occurs at:

Below room temperature

Below transition temperature

At high temperature

None of the above

None

Brittle fracture is best prevented by:

Conducting PWHT

Increasing operating temperature

Using suitable materials for low temperature

All of the above

None

Which of the following NDT detect the possibility of Brittle fracture?

NDT cannot detect possibility of Brittle Fracture

None

Cracks that are typically straight, non-branching, and devoid of any associated plastic deformation are likely associated with which type of failure?

Stress corrosion cracking

Brittle fracture

Thermal fatigue

Temper embrittlement

None

Which of the following are found along the free edge of the fracture, or localized necking around the crack?

Shear lips

Intergranular craking

Necking

None of the above

None

For new equipment, brittle fracture is best prevented by using:

Materials specifically designed for low temperature operation

Changing the design

Changing the atmosphere

All of the above

None

10.

Susceptible vessels should be inspected for pre-existing flaws/defects to detect the possibility of:

Brittle fracture

Atmospheric corrosion

CUI

None of the above

None

11.

The sudden rapid fracture under stress (residual or applied) where the material exhibits little or no evidence of ductility or plastic deformation is referred to as

Brittle fracture

Ductile fracture

Tensile fracture

None of the above

None

12.

Which of the following materials are affected by Brittle fracture?

Carbon steels and Low-alloy steels are of prime concern

400 series SS are also susceptible even if not embrittled

Both the above 2 options are correct

Stainless steels

None

13.

Brittle fracture can occur in a potentially susceptible piece of equipment containing a flaw or other significant stress concentrator. Three primary critical factors are:

The material’s fracture toughness (resistance to crack-like flaws) as indicated in a Charpy impact test or other fracture mechanics test

The size, shape, and stress concentration effect of the flaw

The amount of residual and applied stresses on the flaw

All of the above

None

14.

All the options mentioned below are the appearance or morphology of damage for the brittle fracture except which of the following

Cracks will typically be straight, non-branching, and largely devoid of any associated plastic deformation, although fine shear lips may be found along the free edge of the fracture, or localized necking around the crack may occur

The fracture surface, if undamaged after the initial fracture, will exhibit visible “chevron markings” that point back to the crack origin point

Microscopically, the fracture surface will be composed largely of cleavage, with limited intergranular cracking and very little microvoid coalescence

The attack will be general or localized, depending upon the condition of the coating, if any, and whether or not the moisture is trapped

None

15.

How can we prevent brittle fracture?

Where brittle fracture is deemed a concern, some reduction in the likelihood of a brittle fracture may be achieved by following API 579-1/ASME FFS

For most new equipment, brittle fracture is prevented by using materials compliant with UCS 66 in Section VIII of the ASME BPVC.

Both the above two options are correct

None of the above are correct

None

16.

Susceptible vessels can be inspected for pre-existing crack-like fabrication flaws, as well as for cracking from relevant in-service cracking mechanisms using which of the NDE methods?

(MT), PT, and/or UT

ECT (Eddy Current Testing)

Hardness Testing

Tensile and Bend Test

None

17.

How Inspection and Monitoring for the brittle fracture is being done

Routine inspection is not normally used to detect or mitigate brittle fracture, but awareness of susceptible equipment can help prevent future damage

Susceptible vessels can be inspected for pre-existing crack-like fabrication flaws, as well as for cracking from relevant in-service cracking mechanisms using magnetic particle testing (MT), PT, and/or UT, as applicable

ECT may include a screening technique such as pulsed eddy current (PEC)

Both first and second options are correct

None

18.

None

1 out of 4

Time's up

Caustic Corrosion – 14 MCQ

API 571 (Caustic Corrosion)

Which of the following materials are not affected by caustic corrosion?

Carbon steel

Low alloy steel

400 series ss

300 series ss

None

Caustic corrosion is most often associated with:

Nuclear plants

Boilers and steam generating including heat exchangers

Oil and gas

Petro chemical

None

Caustic corrosion is characterized by,

Uniform corrosion

Pits

Grooves

Cracks

None

Caustic corrosion is best prevented by,

Proper design

Upgrading material

Heat treatment

All of the above

None

In high-solution-strength caustic, temperatures above about ______ °F with the temperature limit depending on the caustic concentration, will cause general corrosion of carbon steel

300°F

500°F

170°F

Room temperature

None

Which of the following material is resistant to caustic corrosion?

300 series ss until passivity is damaged

Low alloy steel

Carbon steel

400 Series

None

Localized corrosion due to the concentration of caustic (alkaline) solutions such as NaOH and KOH, and/or corrosive salts from those solutions, that usually occurs under evaporative or high heat transfer conditions is referred to as

Carbonate corrosion

Caustic corrosion

Alkaline corrosion

None of the above

None

Primarily which of the following materials are affected by caustic corrosion?

carbon steel

low-alloy steels

400 series SS

All of the above

None

Caustic is commonly added to

None of the below options are correct

Both the below 2 options are correct

To treat BFW and may also enter inadvertently during regeneration of demineralizers

To process streams for acid neutralization or as a reactant to remove sulfur or chlorides

None

10.

All the following options are the critical factors for caustic corrosion except

In high-solution-strength caustic, temperatures above about 170 °F (75 °C), with the temperature limit depending on the caustic concentration, will cause general corrosion of carbon steel

Steel cleanliness (level of S, P, and other impurity elements) and grain size have a significant influence on toughness and resistance to brittle fracture

Alkaline solutions or salts may also enter process streams through leaks in condensers or other process equipment

Some contaminants, such as chlorides and hypochlorites, are known to increase the corrosivity of caustic solutions

None

11.

Localized caustic corrosion (caustic gouging) is most often associated with all of the following except

Boilers

Steam-generating equipment

Turbines

Heat exchangers

None

12.

For general caustic corrosion what type of NDE is generally preferred for inspection and monitoring?

UT using a straight beam or UT scanning or other similar techniques can measure general loss.

Eddy Current Testing

Penetrant Testing

Magnetic Particle Testing

None

13.

For localized caustic corrosion what type of NDE is generally preferred for inspection and monitoring? . . .

Manual UT, including UT scanning, or AUT can be used

Angle beam (SWUT or PAUT) or TOFD may be necessary to determine the extent of localized corrosion

RT has also been used within the limits of the technique

Any of the above

None

14.

Below are the inspection and monitoring methods for caustic corrosion except

Routine inspection is not normally used to detect or mitigate brittle fracture, but awareness of susceptible equipment can help prevent future damage

General Corrosion—UT using a straight beam or UT scanning or other similar techniques can measure general loss.

Localized Corrosion—Manual UT, including UT scanning, or AUT can be used. Angle beam (SWUT or PAUT) or TOFD may be necessary to determine the extent of localized corrosion. RT has also been used within the limits of the technique

When internal access is not available (e.g. steam equipment, tubing, small-diameter equipment, or equipment with ports), VT may be performed using a boroscope

None

1 out of 3

Time's up

Caustic Stress Corrosion Cracking (Caustic SCC) – 27 MCQ

API 571 (Caustic Stress Corrosion Cracking)

What are the affected units or equipment with regard to Caustic SCC?

Non-stress-relieved piping and equipment that handles caustic, including H2S

Mercaptan removal units, as well as equipment that uses caustic for neutralization in sulfuric acid alkylation units

HF alkylation units

All of the above

None

Caustic SCC occur in piping and equipment exposed to caustic primarily:

In carbon steel only

Adjacent to non PWHT'd welds

Heat affected zone

All of the above

None

Caustic SCC is characterized by that occur in piping and equipment exposed to caustic (alkaline hydroxide solutions) at elevated temperature

Surface-initiated cracks

Sub-Surface-initiated cracks

Lamination cracks

None of the above

None

What are the affected materials for Caustic Stress Corrosion Cracking

Carbon steel

Low-alloy steels

300 series SS

All of the above

None

Which of the following materials is more resistant to caustic SCC?

Nickel based alloys

Carbon steels

Low alloy steels

300 series SS

None

At what caustic concentration caustic SCC occurs when concentrating mechanism is present?

Less than 100 ppm

1 to 20 ppm

50 to 100 ppm

250 to 500 ppm

None

To prevent caustic SCC PWHT should be carried out at:

1200°F

1150°F

1100°F

1000°F

None

What are the conditions that increase the likelihood and rate of CSCC

Increasing caustic concentration

Increasing temperature

Decreasing the temperature and caustic concentration

Both first and second options are correct

None

To prevent caustic SCC before steam out, equipment should be:

Heat treated

Water washed

Acid cleaned

Sand blasted

None

10.

In preventing Caustic SCC which of the following method is effective

PWHT

Brazing

Fusing

Soldering

None

11.

Susceptibility to caustic SCC in caustic soda (NaOH) and caustic potash (KOH) solutions is a function of all of the following except

Caustic strength

Metal temperature

Stress level

Performing ECT

None

12.

Caustic SCC typically propagates in all of the following except

Parallel to the weld in adjacent base metal, i.e. in the zone of highest welding residual stress

Can also occur in the weld deposit or HAZ

Nickle based alloys

Can be transverse to the weld

None

13.

All of the following are the critical factors for caustic SCC except

Susceptibility to caustic SCC in caustic soda (NaOH) and caustic potash (KOH) solutions is a function of caustic strength, metal temperature, and stress level

Increasing caustic concentration and increasing temperature increase the likelihood and rate of cracking

Decrease caustic concentration and temperature increase the likelihood and rate of cracking

Cracking can occur at low caustic levels if a concentrating mechanism is present. In such cases, caustic concentrations of 50 ppm to 100 ppm are sufficient to cause cracking

None

14.

The pattern of Caustic SCC observed on the steel surface is sometimes described as a ___________

Shear lip

Spider web

Chevron crack

All of the above

None

15.

Cracking in 300 series SS is most often ___________ but can be ___________ even in non-sensitized material

Trans-granular and intergranular

Chevron and shear

Increased and decreased

All of the above

None

16.

All of the following are the appearance or morphology of damage with regard to caustic SCC except

Cracking in 300 series SS is most often chevron form but can be shear form even in non-sensitized material

Caustic SCC typically propagates parallel to the weld in adjacent base metal, i.e. in the zone of highest welding residual stress, but can also occur in the weld deposit or HAZ and can be transverse to the weld

The pattern of cracking observed on the steel surface is sometimes described as a spider web of small cracks

Cracking in 300 series SS is most often transgranular but can be intergranular even in non-sensitized material

None

17.

Nickel-based alloys are more resistant to cracking and may be required at higher temperatures and/or caustic concentrations. However, caustic SCC of these alloys has been observed at high temperatures and this damage has sometimes been referred to as ____________

Brittle fracture

Solid caustic cracking

Molten caustic cracking

Tensile fracture

None

18.

What are the ways for Prevention/Mitigation of caustic SCC?

Thermal stress relief (PWHT) at 1150°F is effective in preventing caustic SCC

Nickel-based alloys are more resistant to cracking

Steam out of non-PWHT’d carbon steel piping and equipment should be avoided

All of the above

None

19.

With regard to caustic SCC, what are the NDE methods used to detect surface breaking cracks

WFMT

ACFM

ECT

All of the above

None

20.

With regard to caustic SCC, what are the NDE methods used to detect size cracks

Angle beam UT (SWUT & PAUT)

MPI and PT

RT and ECT

None of the above

None

21.

With regard to caustic SCC, which NDE method may not be effective for finding tight cracks, because the cracks are oxide filled.

PT and RT

ECT

None

22.

With regard to caustic SCC, which NDE method may not be effective in detecting fine, tight cracks.

ECT

None

23.

With reference to figure 3-15-1, if the concentration of NaOH (caustic) is 20% with temperature 80°F then what would you conclude for the carbon steel material (Refer page-75)

It comes under area "A" where carbon steel material does not require PWHT

It comes under area "B" where carbon steel material require PWHT

It comes under area "C" where application of nickel alloys to be considered

It comes under area "D" where carbon steel material does not require PWHT

None

24.

With reference to figure 3-15-1, if the concentration of NaOH (caustic) is 30% with temperature 180°F then what would you conclude for the carbon steel material

It comes under area "A" where carbon steel material does not require PWHT

It comes under area "B" where carbon steel material require PWHT

It comes under area "C" where application of nickel alloys to be considered

It comes under area "D" where carbon steel material does not require PWHT

None

25.

With reference to figure 3-15-1, if the concentration of NaOH (caustic) is 30% with temperature 260°F then which material you would suggest

It comes under area "A" where carbon steel material does not require PWHT

It comes under area "B" where carbon steel material require PWHT

It comes under area "C" where application of nickel alloys to be considered

It comes under area "D" where carbon steel material does not require PWHT

None

26.

With reference to figure 3-15-1, if the concentration of NaOH (caustic) is less than 2% (sometimes users use 5% as their threshold) with any temperature range 0°F to 280°F (regardless of temperature), then what you would suggest

It comes under area "A" where carbon steel material does not require PWHT

It comes under area "B" where carbon steel material require PWHT

It comes under area "C" where application of nickel alloys to be considered

It comes under area "D" where carbon steel material does not require PWHT

None

27.

With regard to Prevention/Mitigation of caustic SCC, Steam out of non-PWHT’d carbon steel piping and equipment should be avoided. Where necessary, equipment should be ____________ before steaming out, and only low-pressure steam should be used for short periods of time to minimize exposure

Water washed

Grinding

Wire brush

Buffing

None

1 out of 6

Time's up

Chloride Stress Corrosion Cracking (Chloride SCC) – 18 MCQ

API 571 (Chloride Stress Corrosion Cracking)

Surface initiated cracking of 300 series SS and some nickel-based alloys under the combined action of tensile stress, temperature, and an aqueous chloride environment. It is also referred to as

Chloride cracking

Caustic cracking

Corrosion under insulation

Brittle cracking

None

Which of the following materials are highly susceptible to chloride SCC?

Carbon steel

Low alloy steel

300 series SS

All of these

None

Which of the following materials are highly resistant to chloride SCC?

Carbon steel

Nickel-based alloys are highly resistant but not immune.

Low alloy steel

All of the above

None

Chloride SCC usually occurs at metal temperature above:

300°F

140°F

175°F

285°F

None

The potential for cracking increases at lower pH; however, SCC usually does not occur at pH values

Below pH 2

Above pH 2

In between pH 3-5

In between pH 4-6

None

Chloride SCC usually occurs at PH values:

1 to 7

Less than 2

Above 2

None of the above

None

Nickel content of the alloy has a major effect on resistance. The greatest susceptibility occurs in stainless steels with a nickel content of "OR" The greatest susceptibility for chloride SCC is at nickel content of:

8 % to 10 %

8 % to 16 %

6 % to 18 %

8 % to 12 %

None

Alloys with nickel contents above 35 % are highly resistant, and alloys above 45 % are ____________ in refining applications "OR" Above 45% nickel content the chloride SCC possibility are:

Greatest possibility

Nearly immune

Highly resistant

None of the above

None

All of the following are critical factors for chloride SCC except

Chloride content, temperature, pH, tensile stress, presence of oxygen, and alloy composition are critical factors

Increasing levels of chloride increase the likelihood of cracking

pH of above 2 and increasing temperatures increase the potential for cracking

pH of less than 2 and lower temperatures less than 140°F

None

10.

Which of the following are the affected units or equipment with regard to Chloride SCC

Most non-stress-relieved 300 series SS piping and equipment in any process unit

Chloride cracking has occurred in boiler drain lines and water-cooled condensers

Stainless steel drains in hydro-processing units are susceptible to cracking

All of the above

None

11.

With regard to appearance or morphology of damage which of the following is true

Surface-breaking cracks can occur from the process side or externally under insulation

Characteristic stress corrosion cracks have many branches and may be visually detectable as spider web or craze cracking on the surface

Cracking of sensitized 300 series SS may be intergranular

All of the above are true

None

12.

What are the ways in Prevention/Mitigation of chloride SCC?

Materials of construction resistant to Cl- SCC should be used. Carbon steels, low-alloy steels, and 400 series SS are not susceptible to Cl- SCC

When hydrotesting, low-chloride-content water should be used, followed quickly by thorough dryout

Avoid designs that create stagnant regions where chlorides can deposit or concentrate.

All of the above are correct

None

13.

PT can be used for Chloride SCC. However, extremely fine cracks may be difficult to detect with PT. Special surface preparation methods, including _____________, may be required in some cases, especially in high-pressure services.

Polishing or high-pressure water blast

Solvent cleaned with low-pressure water blast

Un-Polished or low-pressure water blast

None of the above

None

14.

With regard to chloride SCC _________ NDE methods can be used on condenser tubes as well as piping and pressure vessels

ECT inspection

UT inspection

Profile RT inspection

All of the above

None

15.

With regard to chloride SCC _________ NDE method can be used to find advanced stages of cracking.

None

16.

Which NDE method often not sensitive enough to detect cracks except in advanced stages where a sufficient network of cracks has developed.

MPT

None

17.

Which of the following NDT methods are preferred to detect chloride SCC?

PT, VT and ECT

PT and UT (pulse-echo or through-transmission)

PT and RT

WFMT and UT (pulse-echo or through-transmission)

None

18.

Critical factors for chloride SCC includes all of the following except

Chloride content, high temperature, pH>2

Tensile stress & presence of carbon dioxide

Alloy composition

pH<2 & temp <140°F

None

1 out of 4

Time's up

Corrosion Under Insulation (CUI) – 33 MCQ

API 571 (Corrosion Under Insulation)

Corrosion of piping, pressure vessels, and structural components resulting from water trapped under insulation or fireproofing is referred to as

Atmospheric Corrosion

Corrosion Under Insulation

Chloride SCC

Caustic SCC

None

Which of the following are affected by CUI (Corrosion Under Insulation)

Carbon steel, low-alloy steels

Austenitic SS (300 series SS), Ferritic SS (400 series SS)

Duplex stainless steels (2000 Series)

All of the above

None

With a high enough rate of wetting and replenishment of the water in the wet insulation, CUI can occur on insulated carbon steel, low-alloy steel, and 400 series SS equipment operating between

10 °F and 350 °F

50 °F and 250 °F

100 °F and 150 °F

150 °F and 250 °F

None

With a high enough rate of wetting and replenishment of the water in the wet insulation, CUI can occur on 300 series SS (where chloride SCC is the concern), equipment operating between

150 °F to 250 °F

100 °F to 250 °F

140 °F to 350 °F

100 °F to 300 °F

None

With a high enough rate of wetting and replenishment of the water in the wet insulation, CUI can occur on duplex SS (where chloride SCC is the concern), equipment operating between

280 °F to 350 °F

180 °F to 250 °F

200 °F to 300 °F

100 °F to 2000 °F

None

CUI will appear in Austenitic & duplex stainless steel as:

General corrosion

Chloride stress corrosion cracking

Caustic stress corrosion cracking

Hydrogen induced cracking

None

For insulated carbon steel components corrosion become "MORE SEVERE" at metal temperature between:

10 °F to 350°F

212°F to 350°F

140°F to 350°F

None of the above

None

Hint

Which of the following equipment are not susceptible to CUI:

Piping or equipment with damaged /leaking steam tracing

Localized damage at paint or coating systems

Termination of insulation in a vertical pipe

Equipment located at upstream of cooling towers

None

The CUI mitigation is best achieved by:

Controlling the operating temperatures

Performing 100% visual inspection

Maintaining the insulation and sealing vapor barriers

Using low chloride insulation

None

10.

Which of the following will reduce the possibility of CUI?

Using closed cell foam glass insulation

Controlling operating temperatures

Operating temperature at 10°F to 350°F

All of the above

None

11.

What are the critical factors for CUI to occur?

Temperature, duration of wetting

Design of the insulation system

Insulation type & environment

All of the above

None

12.

Insulating materials often "hold moisture" that creates corrosion. The ability of insulation to draw and hold water or moisture is known as:

Wicking

Saturation

Wetting

None of the above

None

13.

With regard to CUI, Corrosion rates _______________ with increasing metal temperature up to the point where the water evaporates quickly

Remain same

Decreases

Increase

None of the above

None

14.

Location of equipment is a concern for CUI. Areas of high moisture that require close surveillance of CUI include which of the following:

Areas down-wind from cooling towers, near steam vents

Areas with deluge systems and areas near supplemental cooling with water spray

Areas where acid vapors are present

All of the above are correct

None

15.

Poor design or installation of insulation systems that allow water to become trapped will ____________ CUI

Increase

Decrease

Remain same for

None of the above

None

16.

Insulating materials that __________ can hold water and be more prone to causing extensive CUI

None of the below

Super saturates

Saturates

Wick(absorb) moisture

None

17.

Equipment that operates _________ the water dew point tends to condense water on the metal surface, thus providing a wet environment and increasing the risk of corrosion.

Above

Below

In other location

In protected area from moisture

None

18.

Plants located in areas with _____________ are more prone to CUI than plants located in cool and dry or warm and dry locations.

Near to the desert area

Any of the below 2 options

High annual rainfall

Warmer marine locations

None

19.

Prevention of CUI is best achieved by:

Carefully planned periodic inspections

Using quality coatings

Careful visual exam of insulation covers

None of these are correct

None

20.

Which of the following NDT methods will detect wet insulation?

PT & Ferrite Test

UT & ECT

Neutron backscatter & infrared thermography imaging

Deep penetrating eddy current inspection

None

21.

Poor design and/or installations that allow water to become trapped will increase:

CUI (Corrosion Under Insulation)

Atmospheric corrosion

Galvanic corrosion

All of the above

None

22.

Flame sprayed aluminum coatings have been used on carbon steels. The coating corrodes preferentially by ______________ there by protecting the base metal

CUI

Atmospheric corrosion

Galvanic corrosion

Al of the above

None

23.

Where piping and equipment have been coated beneath the insulation, ___________ can still occur where the coating has been damaged/deteriorated.

Atmospheric corrosion

Localized CUI

Brittle fracture

Caustic SCC

None

24.

Austenitic SS (300 series SS) are subject to SCC if _________________ are present

Chlorides

Copper

Cobalt

Carbon dioxide

None

25.

Below are the temperature ranges of different materials for corrosion to occur. Which of the following are true

CS/Low alloy steel/Ferritic (400 series SS) - (10°F to 350°F)

Austenitic SS (300 Series SS) - (140°F to 350°F)

Duplex SS (2000 Series) - (280°F to 350°F)

All the above are true

None

26.

For chloride SCC to occur we need

Austenitic SS

Wet chlorine (as insulation has chlorine)

Temperature above 140°F

All of the above are required

None

27.

300 series SS and duplex stainless steel are subject to

Pitting

Crevice corrosion

Both the above are correct

Soil corrosion

None

28.

Since most construction materials used in refining are susceptible to CUI damage, mitigation is best achieved by applying an appropriate/quality coating to the equipment prior to insulating.

High-quality, immersion-resistant nonmetallic coatings, properly applied to the surfaces to be insulated, can provide long-term protection

Flame-sprayed aluminum coatings have been used on carbon steels. The coating corrodes preferentially by galvanic action, thereby protecting the base metal

Both the above are correct

None of the above

None

29.

How to minimize the potential for pitting and Chloride SCC on 300 series SS

Low-chloride insulation should be used

High-chloride insulation should be used

Low-cobalt insulation should be used

High-cobalt insulation should be used

None

30.

Some manufacturers supply insulation certified to be low chloride. Thermal insulation materials can be tested as per _____________ to evaluate chloride content and/or ensure it satisfies a specified limit

ASTM C865

ASTM C870

ASTM C881

ASTM C871

None

31.

Non-invasive, commercially available methods can be used to identify CUI damage under the insulation (without removing the insulation) however, these methods should not be expected to find 100 % of the damage. Which of these methods are

GWT (Guide Wave Testing)

RT (including profile, density, flash, radiometric profiling, real-time, computed, and digital)

PEC (Pulsed Eddy Current)

All of the are used to identify CUI damage under the insulation (without removing the insulation)

None

32.

Non-invasive, commercially available methods can be used to identify wet insulation also; however, these methods should not be expected to find100 % of the damage. These includes

Neutron backscatter

Infrared thermography

Both the above are correct

None of the above are correct

None

33.

None

1 out of 7

Time's up

Mechanical Fatigue – 27 MCQ

API 571 (Mechanical Fatigue)

A form of degradation that occurs when a component is exposed to cyclical stresses for an extended period is referred to as

Mechanical Fatigue cracking

Brittle cracking

Ductile cracking

Plastic deformation

None

Examples of mechanical fatigue are:

Dynamic loading due to vibration

Water hammer, or unstable fluid flow

Both the above 2 options are the examples

None of the above are examples

None

The stresses for mechanical fatigue can arise from either mechanical loading or thermal cycling and are typically well:

Above yield strength

Above tensile strength

Below yield strength

Below transition temperature

None

Which of the following are subject to fatigue cracking although the stress levels and number of cycles necessary to cause failure can vary by material

300 series SS

400 series SS

Low alloy steel

All engineering alloys

None

Critical factors related to Mechanical Fatigue and fatigue resistance include:

Geometry of the component

Stress levels & number of cycles

Material properties such as strength, hardness, and microstructure

All of these are correct

None

The most important factor in determining component resistance to Mechanical Fatigue is:

Design

Operation

Material

Time (Number of cycles)

None

As a Design Factors—Fatigue cracks usually initiate on the

Surface at notches

Stress risers under cyclic loading

Any of the above 2 options

None of the above are correct

None

Design Factors—Fatigue cracks usually initiate on the surface at notches or stress risers under cyclic loading. all of the following are common surface features that can lead to the initiation of fatigue cracks, because they act as stress concentrations, EXCEPT which one

Mechanical notches (sharp corners or groves)

Laminations

Tool markings

Grinding marks

None

Stress point below which the fatigue crack will not occur is called:

Crack limit

Fatigue limit

Endurance Limit

None of the above

None

10.

All of the following materials have an endurance limit EXCEPT

Titanium

Nitrogen

Carbon steel

Low-alloy steel

None

11.

For alloys with endurance limits, there is a correlation between ultimate tensile strength (UTS) and the minimum stress amplitude necessary to initiate fatigue cracking, i.e. the endurance limit. The ratio of endurance limit to UTS is typically between _______________

0.1 and 0.4

0.2 and 0.4

0.4 and 0.5

0.5 and 0.8

None

12.

300 series SS, 400 series SS, aluminum, and most other non-ferrous alloys have a fatigue characteristic that does not exhibit an endurance limit. This means that fatigue fracture can be achieved under cyclic loading eventually, given enough cycles, regardless of stress amplitude. Maximum cyclic stress amplitude for design is selected by determining the cyclic stress necessary to cause fracture in the number of cycles the component needs to withstand in its lifetime. This is typically _____________ cycles

10^6 to 10^7 cycles

10^2 to 10^4 cycles

10^4 to 10^6 cycles

10^3 to 10^6 cycles

None

13.

Heat treatment can have an effect on fatigue resistance of a metal. In general, finer-grained microstructures tend to perform better than coarse grained. Heat treatments such as ________________________ can improve fatigue resistance of carbon and low-alloy steels.

Quenching

Tempering

Annealing

Both first and second option are correct

None

14.

Which of the following will have better Fatigue resistance?

Coarse grained steel

Fine grained steel

Steel castings

All of the above

None

15.

With regard to Appearance or Morphology for mechanical fatigue, the signature mark of a fatigue failure is a “___________”-type fingerprint that has concentric rings called “______________” emanating from the crack initiation site

Clam shell and beach marks

Chevron mark and clam shell

Ductile fracture and brittle fracture

Beach mark and brittle fracture

None

16.

With regard to Appearance or Morphology for mechanical fatigue. Mechanical fatigue cracks are characterized by:

Ratchet markings

Clam shell

Beach marks

All of the above

None

17.

Which of the following is the best way to reduce fatigue cracking?

Good design to minimize stress concentration

Selection of suitable material

Controlling operating temperature

Periodic NDT of suspected vessels

None

18.

With regard to Appearance or Morphology for mechanical fatigue, Damage is usually in the form of a crack emanating from a point of high stress concentration or discontinuity such as

Thread

A weld

The corner of a keyway in a shaft

All of the above

None

19.

With regard to Appearance or Morphology for mechanical fatigue, Cracks nucleating from a surface stress concentration or defect will typically result in a single “____________” fingerprint

Beach Mark

Clam shell

Ratchet Marks

none of the above

None

20.

With regard to Appearance or Morphology for mechanical fatigue, Cracks resulting from cyclical overstress of a component without one significant, isolated stress concentration point will typically result in a fatigue failure with multiple points of nucleation and hence multiple “clam shell” fingerprints and these multiple nucleation sites often called “__________”

Ratchet Markings

Clam Shell

Beach Mark

None

21.

Fatigue cracks usually initiate on the surface at:

Tool markings

Grinding marks

Mechanical notches

All of the above

None

22.

Additionally, Which of the following are the ways to prevent fatigue cracking?

Minimize weld defects as these can accelerate fatigue cracking

Minimize grinding marks, nicks, and gouges on the surface of components subject to cyclic loading

Use low-stress stamps and marking tools

All of the above

None

23.

Fatigue cracks can be detected by which NDE method:

MT (including WFMT)

SWUT, PAUT & Compression wave UT

Any of the above

None

24.

Which of the following NDE methods are used to detect fatigue cracks open to the surface.

RT and PT

Below both options are correct

MT (including WFMT)

None

25.

Which of the following NDE methods are used to detect fatigue cracks open to the surface or near to the surface (sub surface)

MT (including WFMT)

Ferrite Test

None

26.

Which of the following NDE method is used to detect fatigue cracks at known or suspected areas of concern, e.g. at stress concentrations and welded connections, and where cracking is internal

Angle beam (SWUT and PAUT)

None

27.

Which of the following NDE method is used to detect fatigue cracking in bolts

Compression wave UT

MT (including WFMT)

ECT

None

1 out of 6

Time's up

Microbiologically Influenced Corrosion (MIC) – 21 MCQ

API 571 (Microbiologically Influenced Corrosion)

Corrosion caused by living organisms such as bacteria, algae, or fungi. It is often associated with the presence of tubercles or slimy organic substances. Often, the bacteria produce localized corrosion in the form of pitting or crevice corrosion is referred to as which type of corrosion

Microbiologically Influenced Corrosion

Mechanical Fatigue

Atmospheric Corrosion

Soil Corrosion

None

Which of the following damage mechanisms associated with living organisms?

Boiler water condensate corrosion

MIC

Cooling water corrosion

All of the above

None

Most common affected material of construction for MIC includes

Carbon and alloy steels

300 series SS and 400 series SS

Aluminum alloys, copper alloys, and some nickel alloys

All of the above

None

Which of the following material is highly resistant to MIC

Titanium

Carbon stell

300 Series SS

400 Series SS

None

Microbiologically influenced corrosion (MIC) is found in aqueous environments. Occasionally it is found in services where _____________ allow and/or promote the growth of microorganisms

Water is intermittently present

Stagnant or low-flow conditions

Both the above 2 options are correct

None of the above

None

With regard to MIC, there are many types, organisms can survive and grow under a wide range of conditions which includes

Lack of oxygen, light or dark, high salinity

pH range of 0 to 12

Temperatures from 0 °F to 235 °F

All of the above

None

For an MIC, additionally what source does an organisms require for their growth

Carbon, Nitrogen & Phosphorous

Argon & Nitrogen

Helium & Argon

None of the above

None

With regard to MIC which of the following are the critical factors

Lack of Oxygen, Light or dark, High salinity

Temperature 0°F to 235°F

pH range of 0 to 12, stagnant water/aqueous environment

All of the above

None

Which of the following equipment will mostly affected by MIC?

Pressure vessels

Caustic Service piping

Storage tank bottom

All of the above

None

10.

Which of the following is a characteristic of MIC damage?

Beach Marks

Spider web

Cup shaped pits within pits

Pitting corrosion

None

11.

With regard to MIC, what are the which of the following are the affected units or equipment

Product storage tanks and water-cooled heat exchangers

Stagnant process piping lines with trapped water

Drain system, fire water system or i the equipment where hydrotest water has not been removed

All of he above

None

12.

With regard to MIC, appearance or morphology of damage is often characterized by _____________ in carbon steel or subsurface cavities in stainless steel

Cup-shaped pits within pits (the halo effect)

Beach Mark

Spider web

None of the above

None

13.

Which of the following are examples of biocides used to prevent MIC

Chlorine, bromine, ozone, ultraviolet light, or proprietary compounds

Helium & argon

Carbon dioxide & nitrogen

Sulphur, magnesium & carbon dioxide

None

14.

To prevent MIC, one of the method is to Minimize low-flow or stagnant zones in water-containing systems. A flow rate of ___________fps, will inhibit colony formation and thereby minimize the likelihood of MIC.

3 fps

6 fps

4 fps

5 fps

None

15.

How underground structures and interiors of storage tanks can be effectively protected from MIC.

Coating and cathodically protecting

Painting interiors of pressure vessels

Without adding biocides

None of the above

None

16.

What are the ways for Prevention/Mitigation of MIC

Adding biocides, Lines should be sloped to assist in drainage

Minimize low-flow or stagnant zones in water-containing systems. A flow rate of 3 fps (1 m/s) will inhibit colony formation and thereby minimize the likelihood of MIC.

Empty hydrotest water as soon as possible

All of the above

None

17.

_________ is usually found in aqueous environments or services where water is sometimes or always present, especially where stagnant or low-flow conditions allow the growth of microorganisms.

MIC

HIC

Atmospheric corrosion

Soil corrosion

None

18.

Proper application of _______ will control but not eliminate microbes that cause MIC so that continued treatment is necessary.

Sulphur

Caustic

Biocides

None of the above

None

19.

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

MIC

HIC

Soil corrosion

Atmospheric corrosion

None

20.

A form of corrosion caused by living organisms such as bacteria, algae or fungi that is often associated with the presence of tubercles or slimy organic substances is known as:

None of these

Atmospheric corosion

Soil Corrosion

MIC

None

21.

Inspection and Monitoring for MIC is done by:

In cooling water systems, effectiveness of treatment is monitored by measuring biocide residual, microbe counts and visual appearance of the water

Special probes designed to monitor for evidence of fouling that may precede or coincide with MIC damage

An increase in loss of duty of a heat exchanger may indicate fouling & potential MIC damage

All of the above are correct, and also foul smelling water is often a sign of trouble with MIC or may indicate biological activity

None

1 out of 5

Time's up

Soil Corrosion – 18 MCQ

API 571 (Soil Corrosion)

Which of the following materials will not be affected by soil corrosion?

Carbon steel

Cast iron

300 series SS

Ductile iron

None

The corrosion of metals from exposure to soils is referred to as

Soil corrosion

Caustic corrosion

Atmospheric corrosion

None of the above

None

The severity of soil corrosion is determined by many factors, including

Operating temperature, moisture and oxygen availability

Soil resistivity, soil type, homogeneity, cathodic protection

Stray current drainage, coating type, age, and condition

All of the above

None

Soil corrosivity is best measured by:

Soil Corrosivity testing

Soil Resistivity testing

Soil conducting testing

Soil Corrosivity cannot be measured

None

Soil-to-air interface areas are often much more susceptible to corrosion than the rest of the structure because of ___________ and __________ availability

Moisture & Oxygen

Oxygen & Nitrogen

Nitrogen & Argon

Moisture & Helium

None

Soil corrosion appears as external thinning with a roughened surface and localized deeper attack or _________

Resistivity

General corrosion

Pitting

Potential

None

Which of the following are true with regard to the critical factors of soil corrosion

Soils having high moisture content, high dissolved salt concentrations, and high acidity are usually the most corrosive

Other factors that affect soil corrosion include galvanic corrosion, dissimilar soils, stray currents, differential aeration corrosion cells, and MIC

Soil-to-air interface areas are often much more susceptible to corrosion than the rest of the structure because of moisture and oxygen availability

All of the above and also Corrosion rates increase with increasing metal temperature

None

All of the following are the affected units or equipment with regard to soil corrosion EXCEPT

Underground piping and equipment

Buried tanks and the bottoms of aboveground storage tanks

Ground supported metal structures

All the equipments which are installed on certain height from the ground level

None

Where ever soil corrosion occurs, all of the following are true with regard to appearance or morphology of damage EXCEPT

Soil corrosion appears as internal thinning with a smooth surface and generally deeper attack or pitting

Poor condition of a protective coating is a tell-tale sign of potential corrosion damage

Soil corrosion can be highly variable along an unprotected buried pipe or on the unprotected underside of a storage tank bottom

Soil corrosion appears as external thinning with a roughened surface and localized deeper attack or pitting

None

10.

The most effective protection of soil corrosion is:

Special Backfill and coating

Corrosion resistant coating

Special backfill and cathodic protection

Combination of corrosion resistant coating and cathodic protection

None

11.

How a cathodically protected line may be used to verify that the buried piping has a protective potential throughout its length.

A close-interval potential survey

By performing PT and MT method

An open-interval potential survey

Corrosivity of a soil

None

12.

______________________ standard is used as a guidance applicable to inspecting and maintaining cathodic protection systems for buried and soil-contacting equipment.

NACE SP0139 and API 652 standard

NACE SP0169 and API 651 standard

NACE SP0179 and API 653 standard

NACE SP0159 and API 650 standard

None

13.

A pipe coating holiday survey (e.g. direct current voltage gradient) can be used to locate coating defects on coated pipes. This can be performed on which of the following

Newly coated pipe before being buried or On pipe that has been excavated

Only on newly coated pipe before being buried

Only on pipe that has been excavated

Cannot be done on pipe that has been excavated or new coated pipe

None

14.

The most common method used for monitoring underground structures is measuring the structure to ________________using dedicated reference electrodes near the structure.

Soil Moisture

Soil Corrosiveness

Soil Potential

Soil Electrolyte

None

15.

Regarding soil corrosion, Soil resistivity is frequently used to estimate soil corrosivity, mainly because it is easy to measure. Soil resistivity is related to:

Soil moisture content

Dissolved electrolytes in soil water

Both A & B are correct

None of these are correct

None

16.

Soils having HIGH moisture content, high dissolved salt concentrations, and high acidity are usually the __________

Most corrosive

Least corrosive

There is no difference

None of the above

None

17.

Other additional factors that affect soil corrosion include all of the following EXCEPT

Galvanic corrosion, dissimilar soils

Stray currents

Differential aeration corrosion cells and MIC

Mechanical vibration called as mechanical fatigue

None

18.

None

1 out of 4

Time's up

Sour Water Corrosion- Acidic – 13 MCQ

Welcome to your API 571 (Sour Water Corrosion-Acidic)

Sour water corrosion is corrosion of steel due to acid sour water containing H2S at a PH between:

1 to 7

4.5 to 7

3.5 to 7

1 to 4.5

None

Which of the following materials is susceptible to sour water corrosion?

Carbon steel

300 Series SS

400 Series SS

Both B and C

None

Which of the following materials are resistant to sour water corrosion

Stainless steels

Copper alloys

Nickel-based alloys

All of the above

None

Sour water corrosion in __________ containing environments may be accompanied by carbonate SCC.

H2O

H2S

CO2

None

All of the following are the critical factors for Sour water corrosion, EXCEPT

H2S content, pH

Temperature, velocity

Oxygen concentration

All of the above

None

300 Series SS can be used for sour water service at temperatures below ________, where Chloride SCC is not likely.

120°F

140°F

150°F

175°F

None

Which of the following NDT method is used to detect sour water corrosion?

Ultrasonic scanning

UT thickness gauging

Both first and second options are correct

None

Corrosion of steel (primarily) due to ___________________ containing H2S at a pH between 4.5 and 7.0. Carbon dioxide (CO2) may also be present as well as other acidic species such as dissolved organic acids.

Acidic sour water

Alkaline sour water

Neutral sour water

None of the above

None

All of the following units or equipment are affected by acidic sour water corrosion, EXCEPT

High NH3 levels & coker gas fractionation plants with low H2S levels

Coker gas fractionation plants with high H2S levels

Low NH3 levels

Overhead systems of FCC

None

10.

Which of the following are true with regard to acidic sour water corrosion (SWC) when pH is above 4.5

A protective, thin, iron sulfide layer helps limit the corrosion rate

Sometimes a thicker, porous sulfide film layer can form promoting pitting under the sulfide deposits

SWC increases as temperature decreases

Both first and second options are correct

None

11.

With regard to Appearance or Morphology of Damage, for SWC- 300 series SS is susceptible to pitting attack and may experience

Crevice corrosion and/or Chloride SCC

Atmospheric corrosion

Soil corrosion

Mechanical fatigue

None

12.

With regard to Prevention/Mitigation of SWC, 300 series SS can be used at temperatures below about ____________ where Chloride SCC is not likely to occur

340 °F

140 °F

240 °F

180 °F

None

13.

Process monitoring and control are important for minimizing the effects of acidic SW corrosion. Which of the following parameters are considered for the Prevention/Mitigation of SWC

H2S content, pH

Chloride content, cyanide content, temperature

Fluid velocity, and oxygen concentration

All of the above

None

1 out of 3

Time's up

Sulphuric Acid Corrosion – 19 MCQ

API 571 (Sulphuric Acid Corrosion)

Which of the following materials is less resistant to sulfuric acid corrosion?

Carbon steel

Alloy 2205

Alloy C-276

Alloy 304 SS

None

Which of the following materials are affected by sulphuric acid

Carbon steel, 316L SS, Alloy 20

High-silicon cast iron, high-nickel cast iron

Alloy B-2, and Alloy C-276

All of the above

None

Which of the following materials is highly resistant to sulfuric acid corrosion?

Carbon steel

Alloy 2205

Alloy C-276

Alloy 304 SS

None

All of the following are the critical factors for sulphuric acid corrosion, EXCEPT

Acid concentration, temperature

Alloy content, velocity, contamination

Presence of oxidizers

Presence of sunlight exposed directly to the surface

None

Carbon steel corrosion rates increase significantly if acid concentration is ____________ and flow velocity _________________

Acid concentration Below 70% and flow velocity exceeds 2fps to 5fps

Acid concentration Below 65% and flow velocity exceeds 2fps to 3fps

Acid concentration Above 65% and flow velocity exceeds 2fps to 8fps

Acid concentration Above 70% and flow velocity exceeds 2fps to 10fps

None

In carbon steel sulfuric acid attacks generally on the:

HAZ

Weld side

Base metal

All of these

None

Acid concentration, temperature, alloy content and __________ are critical factors affecting sulfuric acid corrosion

Pressure

Flow velocity

Stress

Durability

None

Areas of vulnerability in sulphuric acid alkylation units include reactor effluent lines, reboilers, de-iso-butanizer, overhead systems and the _________treating system

Caustic

Sulphuric acid

Catalyst

Hydrogen sulphide

None

With sulphuric acid corrosion, mix points with _____________ cause heat to be released and high corrosion rates occur where the acid becomes diluted "OR" Mix points where acid is mixed with ___________________ cause heat to be released, with the resulting elevated temperature causing an acceleration of the corrosion rate. High corrosion rates can also occur where concentrated acid becomes diluted

Neutral or alkaline Water

Hydrogen gas

Hydrogen sulphide

Caustic

None

10.

A condition where movement of hydrogen bubbles on the steel surface removes the protective film and locally increases the corrosion rate under stagnant or low-flow conditions [

Helium grooving

Carbon grooving

Nitrogen grooving

Hydrogen grooving

None

11.

With regard to critical factor of a sulphuric acid corrosion, Stainless steel performance can be similar to carbon steel, especially in

<92 % H2SO4

At elevated temperatures

Both the above are correct

None of the above are correct

None

12.

Which of the following are true with regard to appearance of sulphuric acid corrosion

“Knife-line” grooving is typical at tops of horizontal piping where hydrogen bubbles form and travel along the top of the pipe. Areas of “fan”-shaped or “delta”-shaped corrosion are common at elbows

Sulfuric acid attacks slag left from welding

If the corrosion rate and velocity are high, there will be no scale

All of the above

None

13.

Sulphuric acid corrosion will have ___________________ at tops of horizontal piping where hydrogen bubbles form and travel along the top of the pipe and areas of ______________________shaped corrosion are common at elbows

“Knife-line” grooving and “fan”-shaped or “delta”

Both will have “Knife-line” grooving

Both will have “fan”-shaped or “delta”

None of the above

None

14.

With sulfuric acid corrosion, the presence of oxidizers can _________ the corrosion rate "OR" The presence of oxidizers (e.g. oxygen) or contaminants (e.g. iron) can greatly ________________ the corrosion rate, especially for Alloy B-2.

Increase

Decrease

No change

Eliminate

None

15.

With sulfuric acid corrosion, Alloy such as Alloy 20 resist dilute acid corrosion and form a protective ____________ film on the surface

Sulphide

Chloride

Iron oxide

Iron sulphate

None

16.

Which of the following alloys resist dilute acid corrosion and form a protective iron sulfate film on the surface.

Alloy C-276

Alloy 20

Alloy 904L

All of the above

None

17.

Which of the following NDT methods is used to detect sulfuric acid corrosion?

UT or RT

Thickness monitoring sensors or Corrosion monitoring with coupons

ER probes

All of the above

None

18.

Which of the following options are true in preventing sulphuric acid corrosion?

Corrosion is minimized through proper materials selection and proper operation within design velocities

Alloys such as Alloy 20, Alloy 904L, and Alloy C-276 resist dilute acid corrosion and form a protective iron sulfate film on the surface

Acidified product streams can be washed with caustic to neutralize the acid

All of the above are correct

None

19.

With regard to figure 3-62-1, if a carbon steel equipment contains 70% of sulphuric acid and having temperature 175(°F) then what would be the corrosion rate for this condition

50 - 200 mils per year

Over 200 mils per year

20 - 50 mils per year

5 - 20 mils per year

None

1 out of 4

Time's up

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