_____________ is the process of coating the surface of steel with aluminium oxide, thereby imparting it increased resistance to corrosion & oxidation upto a temperature of 700°C ?

Related Mcqs:

1. Hot dipping process is used for coating a low melting point metal (e.g. Pb, Sn, Zn) on iron, steel & copper having relatively higher melting points. Which of the following is not a hot dipping process ?

   A. Galvanising
   B. Tinning
   C. Sherardizing
   D. None of these

2. Coating thickness in case of galvanising of steel sheet generally corresponds to the deposition of _______________ gms of zinc per m2 of steel strip ?

   A. 5-10
   B. 1000-1500
   C. 120-500
   D. 1500-3000

3. The thickness of oxide film is y at time t. If K1, K2 and K3 are the temperature dependent constants, the parabolic law of oxidation is given by __________________?

   A. y2 = 2k1t + k2
   B. y = k1 ln (k2t + k3)
   C. y = k1 t + k2
   D. y = k1t3 + k2

4. _______________ is the hardest oxide and is hence used where high wear resistance at high temperature is required?

   A. Beryllium
   B. Zirconia
   C. Alumina
   D. Magnesia

5. High speed steel tools retain their hardness upto a temperature of __________________ °C?

   A. 500
   B. 750
   C. 900
   D. 1100

6. Austempering of steel requires it to be heated to 875°C followed by sudden cooling to 250- 525°C, thereby changing austenite to___________________?

   A. Sorbite
   B. Bainite
   C. Martensite
   D. Troostite

7. The ‘transition temperature’ for ductile to brittle behavior of steel increases with increase in the _____________ content in steel?

   A. Carbon
   B. Manganese
   C. Both A nor B
   D. Neither A nor B

8. Minimum temperature upto which water can be theoretically cooled down in the cooling tower by evaporative cooling is equal to the ______________ temperature of air?

   A. Wet bulb
   B. Dry bulb
   C. Saturation
   D. Dew point

9. High relative humidity decreases the evaporative process and as the temperature is increased, the relative humidity decreases. The comfort range for human body is the ambient temperature of 22 to 27°C with relative humidity ranging from _______________ percent ?

   A. 5 to 10
   B. 15 to 25
   C. 45 to 50
   D. 75 to 80

10. Out of the following, the ________________ pipe has the least corrosion resistance?

    A. Mild steel
    B. Copper
    C. Cast iron
    D. Wrought iron