Free Plant Design and Economics MCQs with Answers

• A. Above 1403
• B. Above 1800
• C. Upto 910
• D. Between 910 & 1403

Explanation: Alpha iron is the body-centred-cubic ferrite form of iron and remains stable from low temperature up to about 910°C, where it changes to…

• A. None of these
• B. Gypsum
• C. Rubber
• D. Talc

Explanation: On the Mohs hardness scale, talc has the minimum hardness, assigned a value of 1.

• A. High toughness
• B. High wear resistance
• C. Poor hardenability
• D. All A., B. & C.

Explanation: Cold-work tool steels must resist abrasion and deformation during cutting or forming, so high wear resistance is essential.

• A. And copper
• B. And graphite
• C. Tin, nickel, iron and chromium
• D. None of these

Explanation: Zircaloy is primarily zirconium alloyed with small amounts of tin, iron, nickel and chromium.

• A. High carbon steel
• B. Wrought iron
• C. Mild steel
• D. None of these

Explanation: An iron-carbon alloy containing about 4% carbon lies in the cast-iron range, whereas steel generally contains less than about 2.1% carbon.

• A. Visual inspection by naked eye
• B. Optical microscope
• C. X-rays
• D. Metallurgical microscope

Explanation: Macrostructure concerns large-scale features such as cracks, segregation and weld defects, which can often be observed by visual…

• A. Cast iron
• B. Either B. & C.
• C. Aluminium
• D. Steel

Explanation: Acetaldehyde can be transported in suitable steel or aluminium drums, provided the containers are properly designed for this volatile…

• A. Cast iron
• B. High silicon iron (14% Si)
• C. Mild steel
• D. Tin lined with refractory bricks

Explanation: Rotary dryers are commonly fabricated from mild steel because it is strong, readily available, weldable, and economical.

• A. Torsion
• B. Tensile
• C. Compressive
• D. Fluctuating

Explanation: Fatigue results from repeated or fluctuating stresses, even when each individual stress is below the material's ultimate strength.

• A. Phosphorus
• B. Silicon
• C. Sulphur
• D. None of these

Explanation: Silicon promotes the formation of a protective, relatively corrosion-resistant film in cast iron and also encourages graphitic carbon…

• A. Plain carbon steel
• B. Stainless steel
• C. Chrome carbon steel
• D. Malleable cast iron

Explanation: Ball bearings require high hardness, wear resistance, and fatigue strength, which are provided by high-carbon chromium steel, commonly…

• A. Pumice stone
• B. Graphite
• C. Carborundum
• D. Diamond

Explanation: Diamond is the hardest naturally occurring material because its carbon atoms are held in a strong three-dimensional covalent lattice.

• A. Increases its melting point
• B. Does not affect its melting point
• C. Makes it malleable
• D. Decreases its melting point

Explanation: Most impurities disrupt the regular iron lattice and lower the melting temperature, so impure iron melts over a lower or broader…

• A. Are used for automobile parts like gears, axle, shaft, bearings etc.
• B. Are prone to temper brittleness
• C. Have very poor fatigue resistance
• D. Do not contain nickel or chromium or both

Explanation: Low-alloy molybdenum steels in this range are valued for strength, hardenability, and fatigue resistance, making them suitable for gears…

• A. Steel
• B. Cast iron
• C. Ferroalloy
• D. None of these

Explanation: Cast iron commonly contains excess carbon in the form of graphite flakes or nodules, whereas in steel most carbon remains chemically…

• A. Inconel
• B. German silver
• C. Hastelloy
• D. Solder

Explanation: Hastelloy is a nickel-based corrosion-resistant alloy family whose important alloying additions commonly include molybdenum, with some…

• A. None of these
• B. Copper & aluminium
• C. Lead & tin
• D. Iron & copper

Explanation: Constantan is a copper-nickel alloy, typically containing about 55% copper and 45% nickel, and is used with copper in thermocouples.

• A. Cast iron
• B. Karbate
• C. Mild steel
• D. Stainless steel

Explanation: Karbate is an impervious graphite material with excellent resistance to hydrochloric acid, making it suitable for HCl absorbers.

• A. Mild steel
• B. 18/8 stainless steel
• C. Molybdenum stainless steel
• D. High silicon iron (14% Si)

Explanation: Molybdenum stainless steel retains high strength and creep resistance at about 500°C while also resisting corrosion under severe pressure.

• A. Brittleness
• B. Toughness
• C. Resilience
• D. Hardness

Explanation: Hardness is the ability of a material to resist scratching, abrasion, or indentation.