MEP WRITTEN NOTES

1. Purpose of Sacrificial anodes to save the metal

2. Composition of Brass, Bronze, Aluminum Bronze

Brass = 70 copper + 30 zinc

Bronze = 88 copper + 12 tin

Gunmetal = 88 copper + 10 tin + 2 zinc

3. Aluminum bronze = aluminum + copper + tin

4. Weight of rudder acts on rudder carrier bearing

5. Rudder clearance can be measured by trammel

6. What is jumping clearance between the rudder pad and rudder stock

7. When zinc is added to mild steel zinc act as a sacrificial anode

8. Direction of a gear pump depends on prime mover

9. For ME LO P/P, centrifugal type is used quantity of discharge is more

10. method of improving corrosion resistance of metal by adding chromium by metal diffusion is called chromising

11. why metal cladding is better method of improving strength - Material is thick compare to the other method.

12. impingement is which type of corrosion - erosion corrosion

13. what kind of corrosion if outlet of heat exchanger throttled n der is turbulence in HX errosion

14. In bilge line, discharge line goes to where(whether OBD or shore connection or OWS)

15. Galvanic series s as follows – Graphite, Au, Ag, Titanium, Ni, Cu, Tin, Bronze, Pb, Stainless steel, Cast iron, Mild steel, Cd, Al, Zn, Mg(least noble). Aluminium will corrode faster than stainless steel

16. Bimetallic corrosion is the accelerated corrosion of one metal placed in contact with a different more noble (less corroding) metal.

17. Sherardising, Chromising, Calorising = Metal diffusion

A. Sherardising = addition of zinc coating

B. Chromising = addition of chromium coating

C. Calorising = addition of aluminium coating

Corrosion resistance:

A. Hot dipping – Zinc is used for this process and aluminium also (0.1mm thickness)B. Metal spraying – Zinc and aluminimumC. Electro plating – zinc , cadmiumD. Metel cladding –

18. When the two metal (dissimilar) placed in electrical continuity are placed in an electrolyte that type of corrosion called – Bimetallic corrosion or galvanic corrossion

19. Cadmium coatings – electro plating

20. Dezincification….removal of zinc frm brass..

21. Carbonizing or case hardening- graphite atmosphere..adding carbon..

22 .Chromising- addition of chromium coating..

23 .Cargo pump discharge y throttled- maintain backpressure

24 .Coating n welding rod…carbonates and silicates…

25. Sea Water pump air leak gland packing –scoring

26 .v/v seats 2 seats-gate and ball.

27 .rotating type….butterfly, ball

28. Anodic protection using zinc anode

• Zinc is insulated to hull

• Zinc is in electrical contunity to hull

29. Bimetallic corrosion internally happens in an alloy

• Impingment corrosion

30. The dipping of aluminum on metal by electroplating is known as Aluminizing