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Q9. (a) Explain fatigue cracking, stating its causes and propagation. (8)

(b) Explain, how poor maintenance and engine overload may contribute to the risk of fatigue cracking of cylinder head holding studs. (8)

Q9. (a) Describe the properties of each of the following alloys used in marine engineering, giving a practical example for which, each is suited:

(i) cupro-nickel

(ii) white metal

(iii) titanium.

b) Discuss the merits of EACH of the following alloys for use in the casting of large propellers:

(i) nickel aluminium bronze (ii) stainless steel.

c) Describe the tests that may be carried out on steel to be used for ship's side plating.

Q3. A. Explain the causes of the formation of mill scale on steel plate. Describe the preparation necessary before the application of conventional paints to the underwater surface of the hull; C. Describe a coating scheme for the underwater hull using conventional paints.

Q8.  With reference to fatigue of engineering components;

(a) Draw an S/N curve for steel, showing the fatigue limit and two representative stress cycle condition on the graph

(b) Explain how a component is designed to avoid fatigue failure, suiting the S/N curve drawn in part (a)

(c) Explain how poor maintenance and incorrect machinery operation can result in fatigue failure even though a component is designed to operate below the fatigue limit.