Session 1: Engineering Material
Unit 3: Material
Textual Question-Answers
Check Your Progress
A. Fill in the blanks
1. ……………. and …………. contain high proportion of iron.
Ans: Cast iron, steel
2. …………….. is an alloy of carbon and iron.
Ans: Steel
3. Steels containing ……………… to …………… carbon are calledplain carbon steels.
Ans: 0.05%, 1.5%
4. Steels containing up to …………… carbon are called dead mildsteel.
Ans: 0.15%
5. Blocks of many automobile and tractor assemblies are made of…………….
Ans: cast iron
B. Multiple choice questions
1. Alloy steels containing up to 5% of total alloying elements arecalled……………
(a) low alloy steels
(b) medium alloy steel
(c) hard steel
(d) None of the above
Ans: (a) low alloy steels
2. Mechanical properties of alloy steel, such as yield strength, ductility, are improved by…………..
(a) alloying
(b) welding
(c) quenching
(d) moulding
Ans: (a) alloying
3. The material used to construct vehicle chassis and framesis…………….
(a) carbon steel or aluminium alloys
(b) iron or chromium
(c) copper or steel
(d) mould material
Ans: (a) carbon steel or aluminium alloys
4. The fast cooling of iron with 2%–4.3% carbonproduces………………
(a) white cast iron
(b) grey cast iron
(c) hard iron
(d) mild cast iron
Ans: (a) white cast iron
5. When white cast iron cools down slowly, the resulting product isknown as…………….
(a) malleable cast iron
(b) hard iron
(c) grey iron
(d) None of the above
Ans: (a) malleable cast iron
C. Answer the following questions
1. Differentiate between glass and rubber.
Ans: Glass is a hard, brittle and transparent material that breaks easily, whereas rubber is soft, elastic and flexible. Glass does not stretch, while rubbercan be stretched and returns to its original shape.
2. Explain the role of plastic in automotive industry.
Ans: Plastic is widely used in the automotive industry due to its light weight, corrosion resistance and easy moulding. It is used in dashboards, bumpers, interior trims, electrical insulation and fuel system components toimprove fuel efficiency and reduce vehicle weight.
