Steel Interview Questions Part-2
Question 11. What Is Case Hardening ?
It is a process of making outer surfaces harder of the steel part. Generally it is done for the following purposes,
To make outer surface harder.
To bring the cost cheaper
To utilize low carbon steel.
Question 12. What Are The Common Heat Treatment Processes Used In Industries ?
The following heat treatment processes are generally used in manufacturing :
Question 13. What Is Meant By Lower And Higher Critical Points ?
While heating a steel part, the temperature raises and it changes the structure of steel part .The temperature point at which the change starts is called lower critical point and the temperature at which the change ends is called higher critical point.
Question 14. Why Heat Treatment Of Steel Is Necessary?
To improve machinability.
To obtain desired properties.
To increase resistance of corrosion.
To change electrical and magnetic properties.
To relieve the stresses after cold or hot working.
To refine the grain size.
Question 15. What Are The Differences Between Brass And Bronze ?
Brass is an alloy of copper and zinc. Generally brass contains 60% copper and 40% zinc. These are used for making bearings, pump fittings, bushes and utensils.
Bronze contains copper and tin. It is comparatively hard, surface wear is less, can be remolded into any shape like wires, sheets, rods etc.
Question 16. What Are The Chemical Composition Of Gun Metal, German Silver And Duralumin ?
Gun metal is an alloy of 88% copper, 10% tin and 2% zinc. It is generally used for casting boiler fittings, bearings ,bushes etc.
German silver is an alloy of copper, nickel, tin and led. It is used for making utensils and resistances in electrical work.
Duralumin is the aluminium alloy contains 3.54.5% copper,0.40.7% magnesium,0.40.7% manganese and remaining aluminium .Mainly used for making bars, tubes, rivets, sheets ,forgings and stampings.
Question 17. What Do You Mean By Stainless Steel ?
It is an alloy steel which contains mainly 8% Nickel and 18% Chromium. Stainless steel main applications in measuring and surgical instruments.
Question 18. How Is Steel Classified ?
According to carbon percentage
- Low carbon steel : Less than 0.25% carbon
- Medium carbon steel: 0.25%0.7% carbon
- High carbon steel: 0.7%1.5% carbon
According to percentage of alloying elements
- Low alloy steel: Alloying element less than 8%
- High alloy steel: Alloying element more than 8%
- Question 19. Why Are Machine Beds Made Of Cast Iron?
Because it has more compressive strength and negligible shrinkage. It can easily cast into any integral shape, wear resisting and can absorb vibrations.
Question 20. How Does Carbon Affects The Properties Of Steel ?
If carbon content is higher the degree of hardness is more and the melting point is lower, If carbon percentage is lower it is easy to forging and forge welding.