GATE 2018 Metallurgical Engineering Answer Key and Explanatory Answers
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2) When she fell down the ___________, she received many _________but little help.” Select the most appropriate option.
A. Stairs, Stares B. Stairs, Stairs C. Stares, Stairs D. Stares, Stares
Answer – (A) Stairs, Stares
3) Inspite of being warned repeatedly, he failed to correct his _______________ behavior.
A. Rational B. Reasonable C. Errant D. Good
Answer – (C) Errant
4) Arrange in descending orders of their volumes.
(i) Cuboid with 10cm x 8cm x 6cm
(ii) Cube with side of 8 cm
(iii) Cylinder with base radius 7cm and height 7cm
(iv) Sphere of radius 7cm
Volume of cuboid = lxbxh = 10x8x6 = 480 cu.cm
Volume of cube = a3 = 8x8x8 = 512 cu.cm
Volume of cylinder = V=πr2 h = (22/7) x 7x7x7 = 1078 cu.cm
Volume of Sphere = V= (4/3) π r3 = (4/3) x (22/7) x (7x7x7) = 1437 cu.cm
Answer – (IV) - (iii) - (ii) - (i)
7) An automobile travel from city A to city B and returns to city A by the same route. It cover the onwards journey @ 60km/hr. and return journey @ 90km/hr. What is the average speed of the entire journey?
A. 72 B. 73 C.74 D. 75
Since equal distances are covered at 60 kmph and 90 kmph, we can apply the formula 2xy/(x+y)
Average speed = (2x60x90) / (60+90) = 72 Km/hr.
Answer – (A) 72 Km/hr.
9) To pass a test, a candidate needs to answer at least 2 out of 3 questions correctly. Total no. of candidates are 6.3 Lacks. Number of candidates that answered correctly to question
A is 3.3 Lacks. Number of candidates that answered correctly to question
B is 2.5 Lacks. Number of candidates that answered correctly to question
C is 2.6 Lacks. Number of candidates that answered correctly to questions
A & B is 1 Lack. Number of candidates that answered correctly to questions
B & C is 90K. Number of candidates that answered correctly to questions
C & A is 80 Lack. If number of students answering all questions correctly is the same as the number of candidates answering none, how many candidates failed to clear the test?
A. 30K B. 2.7 Lacks C. 3.9 Lacks D. 4.2 Lacks
10) In a detailed study of annual crow birth in India, it was found that there was relatively no growth during period 2002-2004 and a sudden spike from 2004 – 2005. In another unrelated study, it was found that revenue from cracker sale in India which remained fairly flat from 2002-2004, saw a sudden spike in 2005 before declining again in 2006. Solid line shows sale of cracker while dash line represents crow birth in the graph. Choose the most appropriate inference from the above data.
A. There is a strong correlation between crow birth and cracker sale.
B. Cracker usage increase crow birth rates.
C. If cracker sale declines, crow birth will decline.
D. Increased birth rate of crows will cause an increase in the sale of crackers.
Ans = A
11) Which of the following materials are protected by passivation (i.e. formation of a thin adherent film on the surface) from corrosion?
P. Aluminium alloys Q. Mild steel
R. Stainless steel S. Silver
a) P & Q b) Q & R c) Q & S d) P & R
12) During upset forging, and considering friction, which of the following profiles represents the axial compressive stress?
Note: In these profiles, the absolute value of the axial compressive stress is plotted on the y – axis.
a) P b) Q c) R d) S
13) Arrange the following processes in INCREASING magnitude of surface roughness of the casting.
P. Investment casting Q. Permanent mould casting
R. Pressure die casting S. Sand casting
a) R < S < Q < P
b) P < S < Q < R
c) R < P < Q < S
d) Q < P < R < S
18) Which of the following welding processes in NOT suitable for joining thin metal sheets?
a) Gas Metal Are Welding b) Electro Slag Welding
c) Electron Beam Welding d) Laser Beam Welding
20) A steel is plastically worked in the temperature range below the nose of the TTT curve and above MS, followed by quenching to produce fine martensite. What is this process called?
a) Martempering b) Ausforming
c) Inter – critical forming d) Normalizing
21) A long oil pipeline made of steel is suspected to have developed a scale on the inner surface due to corrosion. Which of the following non – destructive techniques is the most suitable for detecting and quantifying such a defect?
a) Dye penetrant test b) Magnetic particle inspection
c) Ultrasonic inspection d) Acoustic emission
23rd Answer: We will provide soon. Doublechecking...
24) Consider the following engineering components:
P. Gas turbine blades Q. Tungsten – based heavy alloy penetrators
R. Self – lubricating bearings S. Engine block of an automobile
Which of the following two components are produced by powder metallurgy?
a) P & Q b) Q & R c) Q & S d) P & S
26) To minimize refractory loss during BOF steel – making. Slag is supersaturated with which of the following:
a) Al2O3 b) Fe2O3 c) SiO2 d) MgO
Ans: (D) MgO
As we know that refractory lining of basic oxygen furnace (BOF) is made up of basic material like Magnesite, Dolomite, Pitch impregnated magnesite etc. If we use acidic slag(SiO2,P2O5, etc.), it will react with the furnace lining and makes it thin. To minimize the refractory loss we will produce basic slag by adding excess CaO, MgO etc. to counter the effect of acidic material and also lining of furnace.
27) What is the most – abundant anion in a 2CaO.SiO2 melt?
Discussion Alert: Can answer D also. We are getting conflicting opinion on this question, with more people favoring D. So let us wait for official Answer Key.
Discussion Alert: Can answer be both C and D
Drawing can have edge cracks & surface cracks as drawing can be wire drawing or deep drawing.
In deep drawing there will be edge cracks when the restraint force is very high (and it will have earing when restraint force is moderate)
And rolling also has both surface & edge cracks.
Chevron cracking occurs in Extrusion & Arc welding (but chevron cracking to arc welding mapping is not there in given options). As per given options so both C & D can be correct.
Let us wait for the official key.