UME2405 Material Science & Engineering Metallurgy Department of Mechanical Engineering

UNIT III - FERROUS AND NON-FERROUS METALS

PART A
1. Cite two major reasons for the extensive use of ferrous alloys in engineering applications

Ferrous alloys are iron based alloys that has extensive use in engineering applications due to its
flexibility to meet strength, toughness, and impact of diverse industrial applications.
2. How will you classify steels?
• Plain carbon steels (Low Carbon steels, Medium Carbon steels, High carbon steels)
• Low-alloy steels
• High-alloy steels

3. What is the effect of alloying Silicon and Cobalt in steels?

Silicon improves oxidation resistance, strengthens low alloy steels and acts as a deoxidizer. Cobalt
contributes to red hardness by hardening ferrite, improves mechanical properties such as tensile
strengths, fatigue strength and hardness, refines the graphite and pearlite, a mild stabilizer of carbides,
improves heat resistance and retards the transformation of austenite and thus increases
hardenability and freedom from cracking and distortion.
4. What is the main difference between a brass and a bronze.Also List at least four types of
brasses used.
Brass is an alloy of copper and zinc whereas bronze is an alloy of copper and tin.
Gliding metal ( or commercial bronze), cartr idge brass, st andar d br ass ( or co ld
working brass), Muntz metal (or yellow metal), Naval brass, Admiralty brass.

5. What are three primary groups of plain carbon steels?

Low-carbon steels: Those contain less than 0.25% carbon.
Medium-carbon steels: Those containing between 0.25 and 0.60% carbon.
High-carbon steels: Those containing more than 0.60% carbon.

6. What are the primary effects of chromium, and copper as alloying elements in steel?
Effects of alloying chromium: Increases corrosion and oxidation resistance, increases hardenability,
increases high-temperature strength, and resists abrasion and wear (with high carbon).

Effects of alloying c o p p e r : Increases s t r engt h, a n d inc r e a s e s co rro sio n resistance.

Dr. S. Santosh, AP/Mech/SSNCE 12

 UME2405 Material Science & Engineering Metallurgy Department of Mechanical Engineering

7. Which alloy elements are basically a) carbide(stabilizers) formers, and b) graphite

stabilizers) promoters?
a) Carbide formers: Cr, W, Ti, Mo, Nb, V, and Mn. b) Graphite promoter: Si, Co, Al, and Ni.
8. What makes stainless steel “stainless”?
The chromium oxide (extremely dense-thin) protective layer acts as a barrier to retard further
oxidation, rust or corrosion. As this steel cannot be stained easily, it is called stainless steel.
9. What are the required properties of a tool steel?
Tool steels should have the following properties:
1. Good toughness, 2. Good wear resistance, 3. Very good machinability, 4. Slight change of form
during hardening, 5. Little risk of cracking during hardening. 5. Resistance to softening on heating.

10. What are HSLA steels? Where are they used?

HSLA steels are nothing but high-strength low-alloy steels. HSLA steels, also known as micro
alloyed steels, are low-carbon steels containing small amounts of alloying elements.These HSLA
steels are widely used as structural or constructional alloy steels.
11. What are Maraging steels? Give its composition.
Maraging steels are low-carbon, highly alloyed steels. These are very high- strength materials that
c an be hardened to obtain tensile strengths of up to1900 Mpa. Composition: Maraging steels contain
18% nickel, 7% cobalt, and small amounts of other elements such as titanium. The
carbon content is low, generally less than 0.05%.
12. What is the difference between malleable cast iron and ductile cast iron?
Malleable cast iron is produced by heat treating unalloyed white iron. The ductile (or SG or nodular)
cast iron is produced by adding magnesium and/or cerium to molten cast iron.Both malleable and
ductile cast irons have the nodules, also called spheroids. But the nodules of
ductile cast irons are more perfect spheres.
13. What are the primary effects of adding Ni, and Mo in cast irons?
Alloying
S.No General effects
element
It has graphitizing effect on cementite. So intends to produce a grey
iron.
1. Nickel (Ni)
It has a grain-refining effect, which helps to prevent the formation of
coarse grain.
Molybdenum
2. It increases the hardness of thick sections. It also improves toughness.
(Mo)
14. What are the effects of addition of manganese in steel?
Manganese is an essential alloy that helps convert iron into steel. As an alloy it decreases the brittleness
of steel and imparts strength.
15. State the composition, properties & applications of cupronickel & Monel metal.
The composition of the alloys can vary from 90% Cu–10% Ni to 70% Cu–30% Ni.
Uses: As heat exchanger or condenser tubes in evaporators of desalination plants, process industry
plants, air cooling zones of thermal power plants, high-pressure feed water heaters .

Dr. S. Santosh, AP/Mech/SSNCE 13

UME2405 Material Science & Engineering Metallurgy Department of Mechanical Engineering

Cupronickels are alloys of copper and nickel.

Monel consists of (in %) Ni - 66 , Cu- 31.5, Fe- 1.35, Mn- 0.9 plus residuals.
Uses of monel metal: For making propellers, pump fittings, condenser tubes, steam turbine blades,
sea water exposed parts, tanks, and chemical and food handling plants.

16. What is meant by precipitation hardening?

Precipitation hardening, also known as age hardening, is the most important method of
improving the physical properties of some of the non-ferrous alloys by solid state reaction.
17. The thermal conductivity of a plain carbon steel is greater than for a stainless steel. Why
is this so?
The thermal conductivity of a plain carbon steel is greater than for a stainless steel because the
stainless steel has much higher concentrations of alloying elements. Atoms of these alloying elements
serve as scattering centers for the free electrons that are involved in the thermal transport
process.
18. What is the typical constituent microstructure of bearing alloy?
Also called as white metal, it is an alloy used to provide the best bearing surface in a plain bearing.
It has properties that help reduce friction which make it a good material to use in a plain bearing. The
structure of the alloy is made up of small hard crystals dispersed in a matrix of softer alloy.
Common compositions for Babbitt alloys:
1) 90% tin 10% copper, 2) 89% tin 7% antimony 4% copper, 3) 80% lead 15% antimony 5% tin
Applications: Internal combustion engines use Babbitt metal which is primarily tin-based because it
can withstand cyclic loading. Lead-based Babbitt tends to work-harden and develop cracks but it is
suitable for constant-turning tools such as saw blades.

19. Name any two copper alloy and its composition.

Brass -45% zinc ,55% copper, Cupro nickel – 30% Ni ,70% Cu.
20. What are the effects of adding Tungsten on steels?
Tungsten (W) – increases hardness particularly at elevated temperatures due to stable carbides,
refines grain size.
21. List the major alloying elements of aluminium alloys in 6061 and 7075.
6061 (Al-Si) aluminium alloy's composition roughly includes 0.4–0.8% silicon, 0.7% iron, 0.15–
0.4% copper, 0.4-0.35% chromium and smaller % of titanium, zinc, and other metals.
7075 (Al-) aluminum alloy's composition roughly includes 5.6–6.1% zinc, 2.1–2.5% magnesium,
1.2–1.6% copper, and smaller % of silicon, iron, manganese, titanium, chromium, and other metals.

PART B
1. Sketch the microstructure in different types of cast iron and explain in detail how it affects the
property of cast iron.
2. Explain in detail the effect of major alloying element in copper alloys, state the name, properties
and applications of those alloys formed.
3. Describe the properties and typical applications of Low, Medium and high carbon steels?

Dr. S. Santosh, AP/Mech/SSNCE 14

UME2405 Material Science & Engineering Metallurgy Department of Mechanical Engineering

4. (a) Summarise the effect of the following elements as alloying additions to steels: Mn, Si, Cr,
Mo, V, Ti, Al, Si, Cu, W? (b)What is White Cast Iron? How is Malleable Cast iron produced from
White Cast Iron?
5. Describe the different types of stainless steels, making reference to approximate
compositions, structures, heat treatments and applications?
6. Write an engineering brief about (a)Tool steels (b) HSLA steels (c)Maraging steels (d)High
speed steels?
7.(a) Explain the composition, properties and typical applications of Aluminium alloys? Also
Mention their importance in engineering industry.
(b) What are the types of titanium alloy, their composition, properties and applications?
(c) Explain the composition, properties and typical applications of Nickel alloys.
8. Explain the process of Precipitation strengthening treatment for the Al-4%Cu system?
9. (a) What are the necessary metallurgical characteristics required in a good bearing metal?
(b) Compare and contrast lead- base, tin-base, copper-base and aluminium-base bearing
alloys.
10. Explain the steps involved in precipitation hardening/Strengthening?
11. Explain brief properties and applications of cast iron and also draw the microstructure of any
four types.
12.Explain the various classification of alloys.Discuss the composition, properties and application
of Maraging steel and HSLA steel.

13. It is required to do turning operation of mild steel shaft on a lathe machine. Suggest and discuss
suitable material for the single point cutting tool for this purpose.
14. What is an alloy steel? How are alloy steels classified. Explain them?

15. Why copper is a suitable material for automobile radiators?

Dr. S. Santosh, AP/Mech/SSNCE 15