Question 1

Materials characterization: method used to examine crystal structure (unit cell/space lattice)  Identify the technique that directly reveals crystal structures in solids. Choose the correct option.

Accepted Answer

Concept X-ray diffraction (XRD) directly determines crystal structures (lattice type, lattice parameters) from diffraction patterns. Optical/metallurgical microscopes reveal microstructure (grains, phases) but not the atomic lattice. Final Answer X-ray techniques (e.g., XRD)

Question 2

Blast furnace practice: principal function of coke in the burden  Choose the statement that best describes the role of coke in a blast furnace charge. Select the correct option.

Accepted Answer

Concept Coke serves as both fuel and reducing agent in the blast furnace. It combusts to supply high temperatures and generates CO, which chemically reduces iron oxides to metallic iron. Flux (e.g., limestone), not coke, combines with impurities to form slag. Option analysis • (c) is correct: coke provides heat and participates in reduction via CO. • (a) “controls grade” is not its primary defined role. • (b) coke is not iron-bearing ore. • (d) slag formation is mainly via fluxes reacting with gangue. Final Answer Supplies heat to reduce the ore and melt the iron

Question 3

Heat treatment statement: effect of quenching from the upper critical point  Statement to evaluate: “Quenching steel from the upper critical point results in a fine-grained structure.” Decide if the statement is correct or incorrect.

Accepted Answer

Concept Grain size is governed by the prior austenite grain size, which is influenced by austenitizing temperature and hold time. Quenching mainly controls the transformation product (e.g., martensite), not the grain size already established at temperature. Reasoning Heating much above the upper critical (A3/Acm) promotes grain growth; quenching from there yields hard martensite but does not by itself “refine” grains. Normalizing (proper austenitization just above critical and air cooling) is a standard refinement method. Final Answer Incorrect (False)

Question 4

Crystal structures: identify elements with HCP (hexagonal close-packed) lattice  Select the correct set for HCP among the given choices. Choose the correct option.

Accepted Answer

Concept Typical HCP metals: Zn, Mg, Cd, Co, Ti, Zr, etc. However, antimony (Sb) and bismuth (Bi) are rhombohedral, not HCP. The other sets list FCC (option b) and BCC (option c) metals. Option check • (a) includes HCP members (Zn, Mg, Cd, Co) but incorrectly adds Sb and Bi → set is not purely HCP. • (b) FCC set (γ-Fe, Al, Cu, Pb, Ag, Ni). • (c) BCC set (α-Fe, W, Cr, Mo). Thus, the only correct choice is “None of the above.” Final Answer None of the above

Question 5

Alloying effect: influence of tungsten (W) on the critical temperature of steel  How does adding tungsten to steel affect the critical transformation temperature? Choose the correct trend.

Accepted Answer

Concept Carbide-forming alloying elements such as tungsten (W), molybdenum (Mo), and vanadium (V) generally raise the critical transformation temperature(s) of steel, stabilizing ferrite/carbides and improving hot-hardness. Final Answer Increases the critical temperature

Question 6

Mechanical property definition: fracture with little permanent distortion  Identify the material property corresponding to failure with small plastic deformation before fracture. Choose the correct option.

Accepted Answer

Concept Brittleness is the tendency of a material to fracture with little or no plastic deformation. Ductility and malleability imply significant plastic deformation (tension and compression, respectively). Final Answer Brittleness

Question 7

Effect of free carbon (graphite) in iron: hardness and structure  Free (graphitic) carbon present in iron affects mechanical character and appearance. Choose the most appropriate description.

Accepted Answer

Concept In irons containing free graphite (e.g., grey cast iron), graphite flakes reduce strength and hardness and promote a coarser-looking fracture. The material is relatively soft and exhibits a coarse-grained, crystalline gray appearance. Final Answer Soft and gives a coarse-grained crystalline structure

Question 8

Thermoplastic materials: identify the correct definition and behavior under heat and pressure  Consider the behavior of thermoplastic polymers during heating, forming, cooling, and any associated chemical change. Choose the most accurate description…

Accepted Answer

Given Definition-centric question about thermoplastic behavior. Concept Thermoplastics soften and become formable when heated and solidify when cooled, without a chemical curing reaction. They can be reheated and reshaped multiple times. In contrast, thermosets cure irreversibly into a permanently hard product upon heat and pressure. Reasoning Thermoplastic: softens ⇄ hardens with temperature cycling; no cross-linking reaction.Thermoset: permanent set due to chemical cross-linking under heat/pressure. Eliminate options Option (a) describes thermosets. Options (c) and (d) are application-specific and not defining features. Final Answer Do not become permanently hard by heat and pressure; they soften on heating, harden on cooling, and undergo no chemical change

Question 9

Nonferrous alloys: alloy with a fine gold colour used for imitation jewellery  Among the given copper-based and bearing alloys, identify the one known for a gold-like colour and typical use in imitation jewellery. Choose the correct alloy.

Accepted Answer

Given Identify the alloy with a gold-like appearance commonly used for imitation jewellery. Concept Aluminium bronze (Cu–Al, typically 5–12% Al) exhibits a distinct yellow-gold colour and good corrosion resistance, making it suitable for decorative applications including imitation jewellery. Eliminate options Silicon bronze: typically reddish-brown; excellent corrosion resistance but not especially gold-like. Gun metal: Cu–Sn–Zn; greyish bronze, used for bearings/valves. Babbitt metal: soft bearing alloy (Sn/Sb/Cu or Pb/Sb/Sn), silver-grey, not decorative. Final Answer Aluminium bronze

Question 10

Austenitic stainless steels: method to increase hardness and tensile strength  For 18-8 (austenitic) stainless steels, which treatment/process effectively raises hardness and tensile strength? Select the best option.

Accepted Answer

Given Austenitic stainless steels are to be strengthened/hardened. Concept Austenitic grades (e.g., 304, 316) are not hardenable by conventional quench-and-temper heat treatment. They are strengthened by cold working (work hardening), which increases dislocation density and raises both hardness and tensile strength. Eliminate options Normalising, martempering, and full annealing do not increase hardness in austenitic stainless; annealing generally softens and restores ductility. Note Option (a) is interpreted as work hardening via cold work (proper mechanism). Final Answer Hardening and cold working (work hardening)

Question 11

Crystallography: statements about unit cells  Evaluate standard statements about unit cells (crystal lattices) and choose the most comprehensive correct option. Which is correct?

Accepted Answer

Concept A unit cell is the smallest repeating building block of a crystal lattice. All unit cells in a given single crystal share the same orientation and parallelism of corresponding faces; repeating the unit cell along lattice vectors reconstructs the entire lattice. Why all true (a) Captures the representative nature of the unit cell. (b) Unit cells in a single crystal are identically oriented; similar faces are parallel. (c) The formal definition: a smallest parallelepiped (the unit cell) that, by translation along three non-coplanar vectors, fills space. Final Answer All of the above

Question 12

Allotropy (polymorphism): definition based on crystal structure changes with temperature  Identify the correct statement describing an allotropic material. Choose the correct description.

Accepted Answer

Concept Allotropy (polymorphism in metals) is the ability of a material (e.g., iron, carbon as graphite/diamond) to exist in more than one crystal structure depending on temperature (and sometimes pressure/composition). Eliminate options (a) contradicts allotropy; (b) describes amorphous solids, not crystalline allotropes; (d) is incorrect because only (c) is true for allotropy. Final Answer Exhibits different crystal structures at different temperatures

Question 13

Material property: definition of hardness (ability to resist indentation/scratch)  Select the option that correctly captures the essence of hardness as a mechanical property. Choose the correct statement.

Accepted Answer

Concept Hardness is the resistance to localized plastic deformation (indentation/scratch). A harder material can scratch or indent a softer one. Eliminate options (a) Ductility (wire drawing). (b) Brittleness (tendency to fracture). (d) Malleability (sheet forming). Final Answer It can cut (scratch/indent) another metal

Question 14

Steelmaking at TISCO (Jamshedpur): traditional primary process used historically  Identify which steelmaking process has historically been in operation at Tata Iron and Steel Works (Jamshedpur) as per traditional references. Choose the correct proce…

Accepted Answer

Context Traditional examination references cite the open hearth process as historically practiced at TISCO, Jamshedpur (before widespread adoption of basic oxygen/electric steelmaking). Why not others The Bessemer process was less suited for high-quality control; electric and duplex routes are used, but the classic answer for older plants/MCQs is open hearth. Final Answer Open hearth process

Question 15

Blast furnace charging: location through which the charge is fed  In an iron-making blast furnace, identify the correct region/part through which the solid charge (ore, coke, flux) is fed into the furnace. Choose the correct part.

Accepted Answer

Concept The charge is introduced at the throat (top) of the blast furnace via the charging apparatus (e.g., bell & hopper or bell-less top). The burden then descends through the stack towards the bosh and hearth. Why not others Stack is the shaft region where descending/reaction occurs; bosh is the widest, high-temperature zone; tuyeres introduce hot blast air near the hearth. Final Answer Throat (top)

Question 16

Quality comparison of steelmaking routes: Bessemer/Open-hearth vs. LD (basic oxygen)  Complete the statement about product quality: Steel produced by the Bessemer or open-hearth process is __________ to that produced by the L–D (basic oxygen) proces…

Accepted Answer

Concept The LD (basic oxygen) process provides rapid refining, better control of composition, and generally lower impurity levels (e.g., P, S) than traditional Bessemer/open-hearth routes. Consequently, product quality from LD is typically superior. Therefore Relative to LD steel, Bessemer/Open-hearth steel is considered inferior in quality in classical comparisons. Common pitfall Assuming equality ignores the advances in refining and control inherent in the LD process.

Question 17

Cast irons: element added to produce nodular (spheroidal graphite) iron  Identify the element intentionally added to molten cast iron to produce nodular/spheroidal graphite (SG iron). Choose the correct element.

Accepted Answer

Concept Nodular (spheroidal graphite) cast iron is produced by magnesium treatment (sometimes rare earths like cerium are also used). Mg modifies graphite morphology from flakes to spheroids, improving ductility and toughness. Why not others Ni, Cr, and Cu are alloying elements for strength/corrosion/wear but do not cause graphite nodularisation. Final Answer Magnesium

Question 18

Metallurgy: effect of silicon addition to copper  Silicon is added to copper (silicon bronze) as an alloying element. Which property combination is most improved by silicon in copper alloys? Choose the correct option.

Accepted Answer

Given Silicon is added to copper (forming silicon bronze) to modify properties. Concept / Approach Silicon in copper forms silicon bronzes noted for higher strength with good ductility and corrosion resistance. Machinability improvements in copper are more commonly associated with lead, sulfur, or tellurium additions, not silicon. Option analysis • Machinability: not the primary benefit of silicon in copper alloys. • Hardness or hardness+strength: only partially reflects the effect; silicon bronzes maintain useful ductility. • Strength and ductility: best describes silicon bronze performance. Final Answer Strength and ductility

Question 19

Steel microstructures and hardness ranking  Among common steel microstructures (pearlite, ferrite, cementite, martensite), which one gives the highest hardness under typical heat-treatment conditions? Choose the correct option.

Accepted Answer

Concept Martensite (formed by rapid quenching of austenite) is a supersaturated, body-centered tetragonal phase that is the hardest common steel microstructure. Ferrite is soft and ductile; pearlite is intermediate; cementite is a hard carbide but occurs as a constituent—bulk martensite provides the highest macroscopic hardness in heat-treated steels. Final Answer Martensite

Question 20

Identify the composition of brass (basic metallurgy recall)  Brass is an alloy of which elements? Choose the correct option.

Accepted Answer

Concept Brass = copper + zinc. (Copper + tin is bronze; adding zinc and tin together makes other bronzes or special brasses.) Final Answer Copper and zinc

Engineering Materials Questions