165 + Interview Questions in Eight Forms Of Corrosion in Corrosion Engineering Page 1 InterviewSolution

1.	Which of the following is/are the preventions of erosion-corrosion?(a) Selection of better resistant materials(b) Alteration of the environment(c) Applying protective coatings(d) Selection of better resistant materials, alteration of the environment and applying protective coatingsI had been asked this question during an interview.My question is taken from Eight Forms in chapter Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct answer is (d) Selection of better resistant materials, alteration of the ENVIRONMENT and applying protective coatings The explanation: METHODS for minimizing or PREVENTING erosion-corrosion i. Selection of better resistant materials ii. Design of equipment iii. Alteration of environment iv. Applying protective coatings v. CATHODIC protection of equipment.

Discussion

2.	In which of the following environments that stainless steel will undergo stress-corrosion cracking?(a) Chlorides(b) Caustics(c) Ammonia(d) Chlorides and causticsThe question was posed to me in quiz.The question is from Eight Forms topic in section Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct answer is (d) Chlorides and caustics To ELABORATE: Stainless STEEL undergoes stress-corrosion cracking in chlorides and caustics. They do not CRACK in ammonia, sulfuric acid, NITRIC acid, ACETIC acid, and pure water.

Discussion

3.	Which of the following is/are the preventions of hydrogen embrittlement?(a) Baking of steels at low temperatures (200°F–300°F)(b) Alloying with nickel or molybdenum reduces susceptibility(c) Practicing proper welding with low hydrogen welding rods(d) Baking of steels at low temperatures, alloying with nickel or molybdenum reduces susceptibility and practicing proper welding with low hydrogen welding rods.I had been asked this question in my homework.I'd like to ask this question from Eight Forms topic in section Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct choice is (d) BAKING of steels at LOW temperatures, alloying with nickel or MOLYBDENUM reduces susceptibility and practicing proper welding with low HYDROGEN welding rods. Explanation: Preventions of hydrogen embrittlement are: Baking of steels at low temperatures (200°F–300°F) Alloying with nickel and molybdenum reduces susceptibility Practicing proper welding with low hydrogen welding rods.

Discussion

4.	Which of the following is/are the types of hydrogen damage?(a) Hydrogen blistering(b) Hydrogen embrittlement(c) Decarburization(d) Hydrogen blistering, hydrogen embrittlement, and decarburizationThe question was posed to me in a national level competition.My question is from Eight Forms in section Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct choice is (d) Hydrogen blistering, hydrogen embrittlement, and decarburization The explanation is: CLASSIFICATION of hydrogen DAMAGE: Hydrogen blistering Hydrogen embrittlement Decarburization Hydrogen ATTACK.

Discussion

5.	Which of the following is/are the factors that influence corrosion fatigue?(a) Type of metal(b) Composition of corrosive solution(c) Temperature(d) Type of metal, corrosive solution composition, and temperatureThis question was addressed to me in homework.Question is taken from Eight Forms topic in section Eight Forms of Corrosion of Corrosion Engineering
Answer» Right option is (d) Type of metal, corrosive solution composition, and temperature To explain I would say: The factors that influence CORROSION fatigue: • Type of metal (FCC, BCC, HCP) • Composition of corrosive solution • Temperature • PH of the environment • PERCENTAGE of oxygen content.

Discussion

6.	Which of the following stress-corrosion cracking mechanism is highly acceptable?(a) Dissolution mechanics(b) Mechanical mechanics(c) Both dissolution and mechanical mechanics(d) Hydrogen mechanicsThe question was posed to me in class test.This is a very interesting question from Eight Forms topic in portion Eight Forms of Corrosion of Corrosion Engineering
Answer» The CORRECT OPTION is (a) Dissolution MECHANICS To elaborate: Dissolution mechanics is HIGHLY acceptable than mechanical mechanics. The dissolution model DESCRIBES anodic dissolution at the crack tip, as strain ruptures the passive film at the tip.

Discussion

7.	What is the abbreviation of SCC regarding corrosion?(a) Stress-corrosion cracking(b) Stress-cracking corrosion(c) Stress-corrosion contact(d) Stress-contact corrosionI have been asked this question in an interview for job.My question comes from Eight Forms in chapter Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct answer is (a) Stress-CORROSION cracking The explanation: SCC can be abbreviated as stress-cracking corrosion. It is referred to the simultaneous ACTION of corrosion and stress on a metal structure. Tensile stress is the most common stress that encounters in the INDUSTRIAL WORLD.

Discussion

8.	Which of the following equipment encounters cavitation damage in the service?(a) Hydraulic turbines(b) Ship propellers(c) Pump impellers(d) Hydraulic turbines, ship propellers, and pump impellersI got this question in a job interview.Question is taken from Eight Forms in portion Eight Forms of Corrosion of Corrosion Engineering
Answer» Right CHOICE is (d) HYDRAULIC turbines, ship propellers, and pump impellers Easy explanation: Cavitation damage occurs in hydraulic turbines, ship propellers, pump impellers, and other surfaces where high-velocity LIQUID FLOW and pressure CHANGES are encountered.

Discussion

9.	Which of the following type of equipment is/are highly prone to erosion-corrosion?(a) In piping arrangements at elbows and bends(b) Measuring devices such as orifice and turbine blades(c) In piping arrangements at straight lines(d) In piping arrangements at elbows and bends and measuring devices such as orifice and turbine bladesThis question was addressed to me in semester exam.My doubt is from Eight Forms in chapter Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct answer is (d) In piping arrangements at elbows and BENDS and measuring devices such as orifice and TURBINE BLADES The explanation is: Erosion CORROSION can be affected by the relative velocity of the corrosive solution and metal surface and along with impingement velocity at the edges and turnings. In piping arrangements at elbows and bends and measuring devices such as orifice and turbine blades are the equipment that is prone to erosion-corrosion.

Discussion

10.	What is meant by caustic embrittlement of steel?(a) Failure of cold-worked rivets by a brittle fracture in the presence of ammonia(b) Failure of cold-worked rivets by a brittle fracture in the presence of caustic soda(c) Failure of cold-worked rivets by a brittle fracture in the presence of caustic soda and ammonia(d) Failure of cold-worked rivets by the cup and cone fracture in the presence of caustic sodaThis question was addressed to me in final exam.My question comes from Eight Forms topic in portion Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct option is (b) Failure of cold-worked rivets by a brittle fracture in the PRESENCE of caustic soda Easiest explanation: Explosions of riveted BOILERS that occurred in EARLY steam-driven locomotives are due to the cold working during the OPERATION. Hence, brittle fracture in the presence of caustic RESULTED in caustic embrittlement.

Discussion

11.	As stress-corrosion cracks penetrate the material, the cross-sectional area gets reduced under constant tensile load.(a) False(b) TrueThis question was posed to me during an internship interview.Question is from Eight Forms topic in portion Eight Forms of Corrosion of Corrosion Engineering
Answer» The correct OPTION is (B) True Best explanation: Stress-corrosion cracking is the SIMULTANEOUS ATTACK of corrosion and stress. A stress-corrosion crack penetrates the material; the cross-sectional area GETS reduced under constant tensile stress.

Discussion

12.	Define critical velocity regarding erosion-corrosion.(a) Velocity at which erosion-corrosion starts(b) Velocity at which erosion-corrosion stops(c) Velocity after which erosion-corrosion increases exponentially(d) Velocity after which erosion-corrosion decreases exponentiallyI got this question during an internship interview.The origin of the question is Eight Forms topic in section Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct answer is (C) Velocity after which EROSION-corrosion INCREASES EXPONENTIALLY The explanation is: Critical velocity is the velocity after which the erosion-corrosion increases exponentially. Case 1 (velocity less than critical velocity): Erosion corrosion increases linearly with increase with velocity. Case 2 (velocity greater than critical velocity): Erosion corrosion increases exponentially with increase with velocity.

Discussion

13.	Define the fatigue limit of a metal.(a) Stress below which metal will endure an infinite number of cycles without fracture(b) Stress above which metal will endure an infinite number of cycles without fracture(c) Stress at which metal will endure a less finite number of cycles(d) Stress at which metal will endure a more finite number of cyclesThis question was posed to me during an interview.My question is taken from Eight Forms in chapter Eight Forms of Corrosion of Corrosion Engineering
Answer» The CORRECT choice is (a) STRESS below which metal will endure an infinite number of cycles WITHOUT fracture The best I can explain: Fatigue limit is the stress below which metal will endure an infinite number of cycles without fracture. The fatigue limit can be calculated by (SN CURVE) stress and the number of cycles curve.

Discussion

14.	Which of the following is/are the characteristics of oxide film that exhibits better resistance to erosion-corrosion?(a) Hard(b) Dense(c) Adherent(d) Hard, dense and adherentI have been asked this question in a national level competition.I need to ask this question from Eight Forms in section Eight Forms of Corrosion of Corrosion Engineering
Answer» The correct answer is (d) HARD, dense and adherent The EXPLANATION is: Erosion corrosion is the TYPE of corrosion that results in mechanical DAMAGE of the metal due to the high velocities of corrosive solutions. And a hard, dense, and adherent oxide film can exhibit better resistance to erosion-corrosion.

Discussion

15.	Which of the following metal shows a decrease in corrosion attack with an increase in velocity in fuming nitric acid?(a) Aluminum(b) Carbon steel(c) Stainless steel 347(d) CopperThis question was addressed to me in my homework.I want to ask this question from Eight Forms in section Eight Forms of Corrosion of Corrosion Engineering
Answer» CORRECT CHOICE is (c) Stainless STEEL 347 To explain I would say: Under stagnant conditions, stainless steel 347 in nitric acid is attacked autocatalytically because of the formation of nitrous acid as a CATHODIC reaction product. An increase in velocity sweeps away the CORROSIVE nitrous acid in the environment.

Discussion

16.	Which of the following industries has a major concern on hydrogen blistering?(a) Petroleum industry(b) Chemical manufacturing industries(c) Oil and natural gas refineries(d) Oil and natural gas refineries, petroleum and chemical manufacturing industriesI had been asked this question in a national level competition.The above asked question is from Eight Forms in portion Eight Forms of Corrosion of Corrosion Engineering
Answer» The CORRECT choice is (d) Oil and natural gas REFINERIES, petroleum and chemical manufacturing industries Explanation: Hydrogen blistering refers to the local deformation of a METAL due to the ENTRAPMENT of hydrogen molecules in the metal voids. Industries that have a major CONCERN on hydrogen blistering are: Petroleum industry Chemical manufacturing industries Oil and natural gas refineries Welding workshops.

Discussion

17.	Which of the following is/are the classic cases of fretting corrosion?(a) Bolted tie plates on railroad rails(b) Press-fitted ball bearing race on a shaft(c) On ball bearings(d) Bolted tie plates on railroad rails and press-fitted ball bearing race on a shaftThis question was posed to me in examination.This is a very interesting question from Eight Forms in section Eight Forms of Corrosion of Corrosion Engineering
Answer» The correct option is (d) BOLTED tie plates on railroad rails and press-fitted ball bearing RACE on a shaft Easiest explanation: Fretting corrosion occurs at contact AREAS between materials under load subjected to vibration or repeated relative motion. And it doesn’t occur on materials in CONTINUOUS motion such as on ball bearings.

Discussion

18.	Which of the following is/are the aspects of design to minimize erosion-corrosion?(a) Increasing pipe diameter(b) Avoiding sharp edges and turnings(c) Readily replaceable impingement plates should be inserted(d) Increasing pipe diameter, avoiding sharp edges and turnings and readily replaceable impingement plates should be insertedThe question was posed to me by my school teacher while I was bunking the class.My doubt stems from Eight Forms topic in section Eight Forms of Corrosion of Corrosion Engineering
Answer» The correct answer is (d) Increasing pipe diameter, avoiding SHARP edges and turnings and readily REPLACEABLE impingement plates should be INSERTED For explanation: Design is an important FACTOR to minimize or combat erosion-corrosion. The design includes increasing pipe diameter, avoiding sharp edges and turnings, readily replaceable impingement plates should be inserted, and maintaining certain ANGLES to minimize impingement area.

Discussion

19.	Which of the following metals is/are susceptible to erosion-corrosion?(a) Aluminum(b) Lead(c) Stainless steel(d) Aluminum, lead and stainless steelThe question was posed to me during an internship interview.My question is taken from Eight Forms in division Eight Forms of Corrosion of Corrosion Engineering
Answer» The correct ANSWER is (d) Aluminum, LEAD and stainless steel The best I can explain: Aluminum, lead, copper, and stainless steel are the METALS that are susceptible to erosion-corrosion. Because these metals MAINLY depend on their oxide film for its CORROSIVE resistance.

Discussion

20.	What is meant by hydrogen blistering?(a) Entrapment of hydrogen molecules in the metal voids(b) Formation of brittle metal hydrides(c) Entrapment of metal hydrides in the metal voids(d) Entrapment of hydrogen molecules and metal hydrides in the metal voidsI got this question in an international level competition.I would like to ask this question from Eight Forms topic in division Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct choice is (a) Entrapment of hydrogen molecules in the metal voids Best explanation: Hydrogen BLISTERING refers to the local deformation of a metal due to the entrapment of hydrogen molecules in the metal voids. Initially, hydrogen ATOMS diffuse into metal and react with each other to form a hydrogen MOLECULE.

Discussion

21.	Define Threshold stress regarding stress-corrosion cracking.(a) The maximum stress at which the specimen ruptures(b) The maximum stress required to prevent cracking(c) The minimum stress required to prevent cracking(d) The minimum stress at which cracking startsThis question was addressed to me during an interview for a job.The origin of the question is Eight Forms topic in chapter Eight Forms of Corrosion of Corrosion Engineering
Answer» Right choice is (c) The minimum stress REQUIRED to prevent cracking Explanation: INCREASING stress DECREASES the time before cracking OCCURS. Threshold stress is the minimum stress required to prevent cracking. It depends on temperature, alloy composition, and environment composition.

Discussion

22.	Which of the following is/are the most important variables that affect stress-corrosion cracking?(a) Temperature(b) Metal composition(c) Type and amount of stress applied(d) Temperature, metal composition, and type and amount of stress appliedI got this question during an interview.I need to ask this question from Eight Forms in chapter Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct option is (d) Temperature, metal COMPOSITION, and TYPE and amount of STRESS applied Explanation: The most important VARIABLES that affect stress-corrosion cracking are: i. Temperature ii. Metal composition iii. Corrosive SOLUTION composition iv. Type and amount of stress applied v. Design of metal structure.

Discussion

23.	Which of the following is/are the preventive measures of fretting corrosion?(a) Lubricate with low-viscosity, high-tenacity oil(b) Increasing surface hardness by shot-peening or cold working(c) Use gaskets to absorb vibrations(d) Lubricate with low-viscosity, high-tenacity oil, increasing surface hardness by shot-peening and use gaskets to absorb vibrationsThe question was asked in an internship interview.My question comes from Eight Forms in portion Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct choice is (d) Lubricate with low-viscosity, high-tenacity oil, increasing surface hardness by shot-peening and USE gaskets to ABSORB vibrations Explanation: PREVENTIVE measures to minimize fretting corrosion: i. Lubricate with low-viscosity, high-tenacity oil, and greases ii. Increasing surface hardness by shot-peening or cold working iii. Use gaskets to absorb vibrations and EXCLUDE oxygen at bearing surfaces iv. Increase the LOAD to decrease slip between two metals.

Discussion

24.	Erosion corrosion accelerates the rate of attack on a metal because of relative movement between corrosive fluid and the metal surface.(a) True(b) FalseThis question was posed to me in an internship interview.This intriguing question originated from Eight Forms in chapter Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct answer is (a) True Best EXPLANATION: Erosion corrosion is one of the TYPES of corrosion that accelerates the rate of deterioration or ATTACK on a METAL because of the relative movement of corrosive FLUID and the metal surface.

Discussion

25.	Which of the following is/are the aspects of alteration of the environment to minimize erosion-corrosion?(a) Deaeration of corrosive solution(b) Decrease the temperature(c) Use of Settling and filtration to remove suspended solids(d) Deaeration of the corrosive solution, decrease the temperature and use of settling and filtration to remove suspended solidsThis question was addressed to me in an online interview.Origin of the question is Eight Forms in section Eight Forms of Corrosion of Corrosion Engineering
Answer» The CORRECT choice is (d) DEAERATION of the corrosive solution, decrease the temperature and use of settling and filtration to remove suspended solids The BEST I can explain: Alteration of the environment is also ONE of the methods to minimize erosion-corrosion. This includes the deaeration of corrosive solution, decrease the temperature and use of settling and filtration to remove suspended solids.

Discussion

26.	What is meant by hydrogen embrittlement?(a) Entrapment of hydrogen molecules in the metal voids(b) Formation of brittle metal hydrides(c) Entrapment of metal hydrides in the metal voids(d) Entrapment of hydrogen molecules and metal hydrides in the metal voidsThis question was addressed to me during an online exam.My enquiry is from Eight Forms topic in section Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct answer is (b) FORMATION of brittle METAL hydrides Explanation: HYDROGEN embrittlement refers to the loss of ductility and strength of a metal due to the formation of brittle metal hydrides. Strong hydride forming metals such as titanium, results in brittle fracture.

Discussion

27.	Stress-corrosion cracking occurs due to the simultaneous presence of tensile stress and a specific corrosive medium.(a) True(b) FalseThis question was posed to me in a job interview.Question is taken from Eight Forms topic in section Eight Forms of Corrosion of Corrosion Engineering
Answer» The correct choice is (a) True Explanation: STRESS–corrosion cracking occurs DUE to the simultaneous PRESENCE of tensile stress either is caused by residual or external stress and a specific corrosive medium. Residual stress is caused due to WELDING, cold working, etc.

Discussion

28.	Which of the following type of corrosion that occurs at contact areas between materials under load subjected to vibration or relative motion?(a) Fretting corrosion(b) Crevice corrosion(c) Cavitation damage(d) Pitting corrosionThis question was posed to me in an interview for job.I'm obligated to ask this question of Eight Forms in section Eight Forms of Corrosion of Corrosion Engineering
Answer» The correct answer is (a) Fretting CORROSION Best explanation: Fretting corrosion is the SPECIAL type of erosion-corrosion that occurs at the contact AREAS between MATERIALS under LOAD subjected to vibration or relative motion.

Discussion

29.	What is meant by fatigue?(a) The tendency of a metal to fracture under static loading(b) The tendency of a metal to fracture under repeated cyclic loading(c) The tendency of a metal to fracture under non-repeating cyclic loading(d) The tendency of a metal to fracture after heavy deformationThis question was addressed to me during an interview for a job.My question is taken from Eight Forms topic in section Eight Forms of Corrosion of Corrosion Engineering
Answer» Right option is (b) The tendency of a metal to fracture under repeated cyclic loading Easiest explanation: Fatigue is defined as the tendency of a metal to fracture under repeated cyclic loading. BRIDGES, MACHINES will usually fail DUE to fatigue. It FAILS the metals EVEN below the yield stress of that metal due to repeated cyclic loading.

Discussion

30.	Which of the following is/are the preventions of stress-corrosion cracking?(a) Lowering working stress below the threshold value(b) Shot peening to produce residual compressive stresses(c) Applying for cathodic protection(d) Lowering working stress below the threshold value, shot peening to produce residual compressive stresses and applying for cathodic protectionI had been asked this question during an interview.The above asked question is from Eight Forms in division Eight Forms of Corrosion of Corrosion Engineering
Answer» The CORRECT answer is (d) Lowering working stress below the threshold value, shot peening to produce residual compressive stresses and applying for cathodic protection For explanation: METHODS to prevent stress-corrosion CRACKING are: i. Lowering working stress below the threshold value ii. Shot peening to produce residual compressive stresses iii. Applying cathodic protection to the structure iv. Adding inhibitors to the system v. ELIMINATING the critical environment SPECIES.

Discussion

31.	Which of the following metal is resistant to seawater, chlorides, and fuming nitric acid?(a) Aluminum(b) Lead(c) Titanium(d) Stainless steelI got this question during an interview.My doubt stems from Eight Forms topic in portion Eight Forms of Corrosion of Corrosion Engineering
Answer» Right option is (d) Stainless steel Explanation: Titanium is highly resistant to seawater, CHLORIDES, and FUMING NITRIC acid. It is also resistant to erosion-corrosion because of its high reactivity and stability of oxide film.

Discussion

32.	What is meant by season cracking of brass?(a) Stress-corrosion cracking failure of brass cat ridge cases due to ammonia(b) Stress-corrosion cracking failure of brass cat ridge cases due to caustic soda(c) Stress-corrosion cracking failure of brass cat ridge cases due to caustic soda and ammonia(d) Stress-corrosion cracking failure with brittle fractureThis question was posed to me in examination.My query is from Eight Forms topic in section Eight Forms of Corrosion of Corrosion Engineering
Answer» Right choice is (a) Stress-corrosion cracking failure of brass cat ridge CASES due to AMMONIA Explanation: Season cracking refers to the stress-corrosion cracking failure of brass cat ridge cases. The main important ENVIRONMENTAL component in season cracking is ammonia, which results from the DECOMPOSITION of organic matter.

Discussion

33.	Which of the following is/are the other names of fretting corrosion?(a) Friction oxidation(b) Wear oxidation(c) False brinelling(d) Friction oxidation, wear oxidation and false brinellingThe question was asked in an interview for job.This is a very interesting question from Eight Forms in section Eight Forms of Corrosion of Corrosion Engineering
Answer» The correct answer is (d) FRICTION oxidation, wear oxidation and false brinelling The best I can explain: FRETTING corrosion is ONE of the special types of erosion-corrosion. It also called friction oxidation, wear oxidation, CHAFING, and false brinelling. Because it gets initiated with wear or friction and oxides debris are FORMED during corrosion.

Discussion

34.	Hydrogen damage refers to the mechanical damage of a metal caused by the presence of or interaction of hydrogen.(a) True(b) FalseI have been asked this question in examination.Question is from Eight Forms in division Eight Forms of Corrosion of Corrosion Engineering
Answer» The correct option is (a) True To EXPLAIN I would say: Hydrogen damage refers to the mechanical damage of a metal CAUSED by the presence of or interaction of hydrogen. And hydrogen damage can be classified into four types based on the MECHANISM of FAILURE.

Discussion

35.	Which of the following is/are the facts that indicate the reduction in fatigue resistance of metal?(a) Corrosion pits act as stress raisers(b) Corrosion pits act as initiate cracks(c) Corrosion pits act as a stress raiser and initiate cracks(d) Corrosion pits neither act as stress raiser nor initiate cracksThis question was posed to me in quiz.My enquiry is from Eight Forms topic in chapter Eight Forms of Corrosion of Corrosion Engineering
Answer» RIGHT option is (c) CORROSION pits act as a STRESS raiser and initiate cracks Easy explanation: Corrosion fatigue is the combination of both corrosion and fatigue simultaneously. Fatigue RESISTANCE is reduced because corrosion pits act as stress raisers and initiate cracks.

Discussion

36.	Which of the following type of compounds act as an inhibitor for hydrogen-ion reduction?(a) Sulfide ions(b) Phosphorous compounds(c) Arsenic compounds(d) Sulfide ions, phosphorous and arsenic compoundsI had been asked this question at a job interview.The question is from Eight Forms topic in section Eight Forms of Corrosion of Corrosion Engineering
Answer» Right answer is (d) Sulfide ions, phosphorous and arsenic compounds Explanation: HYDROGEN atoms DIFFUSE into steel and other metals, which results in hydrogen blistering and hydrogen embrittlement. These inhibitors such as sulfide ions (POLYSULFIDE ion), phosphorous, and arsenic compounds reduce the RATE of hydrogen-ion reduction.

Discussion

37.	Erosion corrosion results when the protective oxide films are damaged and the metal or alloy are attacked at a rapid rate.(a) True(b) FalseI have been asked this question in exam.My question is from Eight Forms in division Eight Forms of Corrosion of Corrosion Engineering
Answer» The correct choice is (a) True For explanation I would say: As the relative MOVEMENT of the corrosive SOLUTION and the surface of the metal increases the intensity of erosion-corrosion increases. At higher velocities, it RESULTS in the damage or WORN out of oxide film and it attacks the metal RAPIDLY.

Discussion

38.	Which of the following is/are the metallurgical factors that affect stress-corrosion cracking?(a) Chemical composition(b) Distribution of precipitates(c) Dislocation interactions(d) Chemical composition, distribution of precipitates and dislocation interactionsI got this question in class test.My doubt is from Eight Forms in division Eight Forms of Corrosion of Corrosion Engineering
Answer» Right option is (d) Chemical composition, distribution of precipitates and dislocation interactions Easy explanation: METALLURGICAL factors that affect stress-corrosion cracking are: i. AVERAGE chemical composition ii. PREFERENTIAL orientation of grains iii. Distribution of precipitates iv. Dislocation interactions v. DEGREE of METASTABILITY.

Discussion

39.	Which of the following type of directional patterns usually exhibit by erosion-corrosion?(a) Grooves(b) Waves(c) Rounded holes(d) Grooves, waves and rounded holesThis question was addressed to me by my school principal while I was bunking the class.My query is from Eight Forms in chapter Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct option is (d) GROOVES, waves and ROUNDED holes The explanation is: Erosion corrosion results in wear or ABRASION of the surface of the metal. It is CHARACTERIZED in appearance by grooves, gullies, waves, rounded holes, and valleys.

Discussion

40.	Which of the following type of corrosion in which corrosion occurs due to the presence of hydrogen sulfide?(a) Hydrogen embrittlement(b) Hydrogen blistering(c) Sulfide stress corrosion(d) Erosion corrosionI got this question during an online exam.The origin of the question is Eight Forms topic in chapter Eight Forms of Corrosion of Corrosion Engineering
Answer» Right choice is (c) Sulfide stress corrosion For explanation I would say: Sulfide stress cracking occurs in the presence of water and HYDROGEN sulfide. It is highly concerned with PETROLEUM INDUSTRIES and OIL refining industries.

Discussion

41.	Which of the following metal is highly susceptible to hydrogen embrittlement?(a) Titanium(b) Nickel(c) Martensitic iron-base alloys(d) Titanium and martensitic iron-base alloysThis question was posed to me in an interview.The origin of the question is Eight Forms in chapter Eight Forms of Corrosion of Corrosion Engineering
Answer» RIGHT option is (d) Titanium and martensitic iron-base alloys The best I can explain: Hydrogen embrittlement refers to the brittle cracking failure of reactive METALS due to the formation of METAL hydrides. Titanium, ferritic, and martensitic iron-base alloys are susceptible to hydrogen embrittlement.

Discussion

42.	Which of the following is/are the preventions of corrosion fatigue?(a) Use of high tensile strength metals(b) Perform shot penning to induce compressive stresses(c) Use coatings such as electrodeposited zinc, nickel(d) Use of high tensile strength metals, perform shot penning to induce compressive stresses and use of coatings such as electrodeposited zinc, nickelThis question was posed to me in semester exam.My enquiry is from Eight Forms in division Eight Forms of Corrosion of Corrosion Engineering
Answer» Right answer is (d) Use of high tensile strength metals, perform shot penning to INDUCE COMPRESSIVE stresses and use of COATINGS such as electrodeposited zinc, nickel For explanation I would say: Methods to prevent corrosion FATIGUE: • Use of high tensile strength metals • Perform shot penning to induce compressive stresses • Use coatings such as electrodeposited zinc, nickel, chromium, COPPER and nitride coatings.

Discussion

43.	Which of the following alloy in which both intergranular and trans-granular cracking occurs?(a) High-nickel alloys(b) iron-chromium alloys(c) Brasses(d) High-nickel alloys, iron-chromium alloys, and brassesI had been asked this question in a national level competition.I'm obligated to ask this question of Eight Forms in portion Eight Forms of Corrosion of Corrosion Engineering
Answer» RIGHT choice is (d) High-nickel alloys, iron-chromium alloys, and brasses Explanation: Stress-corrosion CRACKING can be INTERGRANULAR and trans-granular cracking. Alloys such as high-nickel alloys, iron-chromium alloys, and brasses often CRACK both in intergranular and transgranular manner.

Discussion

44.	Which of the following will result due to cavitation damage of a metal?(a) Mechanical action(b) Chemical dissolution(c) Both mechanical action and chemical dissolution(d) Neither mechanical action nor chemical dissolutionThe question was asked in an interview for internship.The origin of the question is Eight Forms in chapter Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct answer is (C) Both mechanical action and chemical DISSOLUTION To explain I WOULD say: Cavitation damage is the special form of erosion-corrosion that occurs by the formation and collapse of vapor bubbles in a liquid near a metal surface. It results in the mechanical and chemical dissolution of metal.

Discussion

45.	Which of the following is/are the classic examples of stress-corrosion cracking?(a) Season cracking of brass(b) Caustic embrittlement of steel(c) Season cracking of brass and caustic embrittlement of steel(d) Neither season cracking of brass nor caustic embrittlement of steelThe question was asked in semester exam.I want to ask this question from Eight Forms topic in portion Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct OPTION is (C) Season cracking of BRASS and caustic embrittlement of steel To explain I would SAY: The two main classic examples of stress-corrosion cracking are: i. Season cracking of brass ii. Caustic embrittlement of steel.

Discussion

46.	Which of the preventions is/are the preventions of hydrogen blistering?(a) Use of clean steel instead of rimmed steel(b) Applying metallic, inorganic and organic coatings(c) Use of substituting alloys such as nickel-based alloys(d) Use of clean steel instead of rimmed steel, applying metallic, inorganic and organic coatings and use of nickel-based alloysThe question was posed to me during a job interview.This is a very interesting question from Eight Forms in section Eight Forms of Corrosion of Corrosion Engineering
Answer» Right choice is (d) Use of CLEAN steel INSTEAD of rimmed steel, applying METALLIC, inorganic and organic COATINGS and use of nickel-based alloys Easiest explanation: Preventions of hydrogen blistering are: Use of clean steel instead of rimmed steel Applying metallic, inorganic and organic coatings Use of substituting alloys such as nickel-based alloys Removing poisons such as sulfides, arsenic compounds, cyanides, and phosphorus IONS.

Discussion

47.	Cavitation damaged can be reduced by changing the design to minimize hydrodynamic pressure differences in process streamflow.(a) False(b) TrueThis question was addressed to me during an internship interview.I need to ask this question from Eight Forms topic in division Eight Forms of Corrosion of Corrosion Engineering
Answer» Right option is (b) True Explanation: CAVITATION DAMAGED can indeed be reduced by changing the design to minimize HYDRODYNAMIC pressure differences in process streamflow. It reduces the impingement area and FORCE of the STREAM.

Discussion

48.	Which of the following environmental factor plays an important role in erosion-corrosion?(a) Velocity(b) Corrosive concentration(c) pH of the environment(d) Relative humidity of the atmosphereI have been asked this question in homework.I would like to ask this question from Eight Forms topic in portion Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct choice is (a) VELOCITY Explanation: Erosion corrosion accelerates the rate of attack on a metal because of relative movement between CORROSIVE fluid and the metal surface. It increases as the velocity of the corrosive SOLUTION increases.

Discussion

49.	Which of the following condition is/are correct regarding the boiling point of a liquid with an increase in pressure?(a) Decreases up to triple point(b) Increases up to triple point(c) Increases up to the critical point(d) Decreases up to the critical pointThe question was posed to me at a job interview.I'm obligated to ask this question of Eight Forms in chapter Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct choice is (a) Decreases up to triple point The BEST I can explain: As the PRESSURE of a liquid decreases, its boiling point decreases up to its triple point. As the pressure increases its increases up to a critical point. Example: At higher altitudes boiling point of liquids reaches low as ATMOSPHERIC pressure decreased.

Discussion

50.	Which of the following type of corrosion is caused by the formation and collapse of vapor bubbles in a liquid near the metal surface?(a) Filiform corrosion(b) Fretting corrosion(c) Cavitation damage(d) Crevice corrosionThis question was addressed to me in exam.The question is from Eight Forms in division Eight Forms of Corrosion of Corrosion Engineering
Answer» Correct choice is (C) Cavitation damage Best explanation: Cavitation damage is the SPECIAL form of erosion-corrosion that occurs by the FORMATION and collapse of vapor bubbles in a liquid near a metal surface.

Discussion

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In which of the following environments that stainless steel will undergo stress-corrosion cracking?(a) Chlorides(b) Caustics(c) Ammonia(d) Chlorides and causticsThe question was posed to me in quiz.The question is from Eight Forms topic in section Eight Forms of Corrosion of Corrosion Engineering

As stress-corrosion cracks penetrate the material, the cross-sectional area gets reduced under constant tensile load.(a) False(b) TrueThis question was posed to me during an internship interview.Question is from Eight Forms topic in portion Eight Forms of Corrosion of Corrosion Engineering

Stress-corrosion cracking occurs due to the simultaneous presence of tensile stress and a specific corrosive medium.(a) True(b) FalseThis question was posed to me in a job interview.Question is taken from Eight Forms topic in section Eight Forms of Corrosion of Corrosion Engineering

Which of the following metal is resistant to seawater, chlorides, and fuming nitric acid?(a) Aluminum(b) Lead(c) Titanium(d) Stainless steelI got this question during an interview.My doubt stems from Eight Forms topic in portion Eight Forms of Corrosion of Corrosion Engineering

Hydrogen damage refers to the mechanical damage of a metal caused by the presence of or interaction of hydrogen.(a) True(b) FalseI have been asked this question in examination.Question is from Eight Forms in division Eight Forms of Corrosion of Corrosion Engineering

Erosion corrosion results when the protective oxide films are damaged and the metal or alloy are attacked at a rapid rate.(a) True(b) FalseI have been asked this question in exam.My question is from Eight Forms in division Eight Forms of Corrosion of Corrosion Engineering