Engineering Materials Practice Set-1

21. Bell metal contains

85 - 92% copper and rest tin with little lead and nickel

90% copper and 10% tin

70 - 75% copper and rest tin

70% copper and 30% zinc

22. Pick up the wrong statement Nickel and chromium in steel help in

Raising the elastic limit

Providing high strength at elevated temperatures

Improving machining properties

Providing corrosion resistance

23. Which of the following statement is wrong?

Steel with 0.8% carbon is wholly pearlite

The amount of cementite increases with the increase in percentage of carbon in iron

A mechanical mixture of 87% cementite and 13% ferrite is called pearlite

The cementite is identified as round particles in the structure

24. In process annealing, the hypo eutectoid steel is

Heated below or closes to the lower critical temperature and then cooled slowly

Heated from 30°C to 50°C above the upper critical temperature and then cooled in still air

Heated from 30°C to 50°C above the upper critical temperature and then cooled slowly in the furnace

Heated from 30°C to 50°C above the upper critical temperature and then cooled suddenly in a suitable cooling medium

25. Nickel in steel

Improves wear resistance, cutting ability and toughness

Refines grain size and produces less tendency to carburisation, improves corrosion and heat resistant properties

Gives ductility, toughness, tensile strength and anti-corrosion properties

Improves cutting ability and reduces hardenability

26. Body centered cubic space lattice is found in

None of the above

Alpha iron, tungsten, chromium and molybdenum

Zinc, magnesium, cobalt, cadmium, antimony and bismuth

Gamma iron, aluminium, copper, lead, silver and nickel

27. A coarse grained steel

Is more ductile and has a greater tendency to distort during heat treatment

Is more ductile and has a less tendency to distort during heat treatment

Is less tough and has a less tendency to distort during heat treatment

Is less tough and has a greater tendency to distort during heat treatment

28. Y-alloy contains

5 to 6% tin, 2 to 3% copper and rest aluminium

3.5 to 4.5% copper, 0.4 to 0.7% magnesium, 0.4 to 0.7% manganese and rest aluminium

3.5 to 4.5% copper, 1.2 to 1.7% manganese, 1.8 to 2.3% nickel, 0.6% each of silicon, magnesium and iron, and rest aluminium

4 to 4.5% magnesium, 3 to 4% copper and rest aluminium

29. In a hardening process, the hypo-eutectoid steel is

Heated from 30°C to 50°C above the upper critical temperature and then cooled slowly in the furnace

Heated below or closes to the lower critical temperature and then cooled slowly

Heated from 30°C to 50°C above the upper critical temperature and then cooled suddenly in a suitable cooling medium

Heated from 30°C to 50°C above the upper critical temperature and then cooled in still air

30. For a steel containing 0.8% carbon

There is no critical point

There is only one critical point

There can be any number of critical points

There are two critical points

Engineering Materials Practice Set-1

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