Why cold working of metal is important in engineering?

Give two (2) examples of processes for cold working.

After high level of cold work, the material becomes very difficult to further work or form.  If it must be formed, what is the necessary process need to be done to the material? Why and how to do it?

Explain the necessity of heat treatment for steel.

What is the purpose of the reduced-section tensile test, the root bend test, the face bend test, and the side bend test?

The presence of harmful elements such as sulfur, phosphorous, oxygen, hydrogen, and nitrogen can affect the properties of iron-carbon alloys.  Describe the effect of each element on the properties of the iron-carbon steel.

Why is creep testing important? Describe and illustrate creep testing and the behavior of the specimen during creep test.

What can the effect of creep be on a structural metal?

Define the following terms: Ultimate tensile strength, 0.1% proof stress, yield strength; and maximum allowable stress

Describe fatigue testing methods.  Explain how does grain size, surface finish, corrosion and temperature can influence fatigue strength of a component.

State the difference between ferrous alloys and nonferrous alloys.  Give two (2) typical examples of the alloys and their alloying elements, and the composition range.

Describe and illustrate with the aid of sketches, the process of extrusion in relation to the fabrication of machinery parts and components.

Describe and illustrate with the aid of sketches, the process of stretch forming in relation to the fabrication of machinery parts and components.

Describe and illustrate with the aid of sketches, the process of forging in relation to the fabrication of machinery parts and components.

Sketch a typical load-extension curve obtained from tensile test carried out on a low carbon steel specimen; and

Sketch the iron-carbon equilibrium diagram for steel up to 2% carbon content and temperature ranging from ambient to 1,000^oC.

Sketch a typical load-extension curve obtained from tensile test carried out on an aluminum alloy specimen.

State typical values of tensile and yield strength of a boiler plate material.

Write a short note on the following and show the equilibrium diagram the existence of those components.

a)     Austenite 

b)     Ferrite

c)     Pearlite 

d)     Cementite

e)     Martensite

Why mechanical properties of metal important? What is the significance of the stress-strain diagram?

What are the two main parameters which are used to describe the strength of a metal? Explain that parameters with the aid of graphs where appropriate.  State its unit of measurement.

What is meant by modulus of elasticity and explain its importance in a physical sense. 

How is modulus of elasticity applied to boiler construction?

What are the two main parameters which are usually used to describe the ductility of a metal? Explain the parameters and state its unit of measurement.

Explain what is metal casting?  Describe and illustrate the following processes:

a)    Sand casting

b)    Die casting

c)    Investment casting

Write a short note on the following:

a)        Stress relieving

b)        Spherodizing

c)        Case hardening

The following destructive mechanical tests are usually conducted on the welding specimen of the boiler shell plate.  In each case describe and illustrate how the test is carried out and explain the importance of the mechanical test

a)        Macro examination

b)        Tensile test

c)        Bend test

Describe the structural changes which take place when plain carbon eutectoid steel is slowly cooled from austenitic region just above the eutectoid temperature.  Distinguish among the following three types of plain carbon steels:

a)  Eutectoid

b)     Hyper-eutectoid

c)     Hypo-eutectoid

Write an essay on each of the following:

a)         Annealing

b)         Hardening

c)         Tempering

d)         Normalizing

Briefly describe the mechanical tests for strength properties.

Describe briefly the procedures in tensile testing.

What is meant by allowable stress and how it is determined?

Name the parts of boilers that must be considered for stress calculation.

Sketch the iron-carbon equilibrium diagram for steel with less than 1.0% carbon and indicate the zones for annealing, normalizing, tempering, and stress relieving.

Explain in brief the difference between hardness and hardenability.

Hardening, tempering, annealing, normalizing, spheroidizing, and case hardening are the most common heat treating processes used for ferrous metals.  Among them, what is the process used for nonferrous metal heat treatment?

Many cutting tools and pieces of equipment must be hardened and tempered before they are used. Explain why and the process of hardening and tempering these tools.

Explain on why tempering is to be done after quenching?

What is the range of Brinell hardness of typical boiler steel plate material?

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