This set of Foundry MCQs focuses on “Electric Arc Furnace”.
1. Induction _______ is the principle of Induction furnace
Explanation: The Induction heating is the process by which the passage of an electric current through a conductor releases heat. Hence it is a principle used in Induction furnace.
2. The currents induced in the electromagnetic induction principle for induction furnace is called _____
a) Direct current
b) Indirect current
c) Eddy currents
d) Electric current
Explanation: The energy transfer to the object to be heated occurs by means of electromagnetic induction. Any electrically conductive material placed in a variable magnetic field is the site of induced electric currents, called eddy currents, which will eventually lead to joule heating.
3. Joule heating is called as resistive heating.
Explanation: The heat which is produced in the joule heating is directly proportional to the square of the current multiplied by the electrical resistance of the wire used. Hence, joule heating is termed as resistive heating or ohmic heating.
4. Induction heating in Induction furnace relies on ______________ frequency.
Explanation: Induction heating relies on radio frequency as it is a part of electromagnetic wave that portion of electromagnetic spectrum below infrared and microwave energy. Since heat is transferred to the product via electromagnetic wave, it never comes in direct contact with any flame, the indicator doesn’t get hot and there is no product contamination.
5. Induction furnace usage has the highest refining capacity.
Explanation: Induction furnace has a lack of refining capacity; the charge materials must be clean of oxidation products and of oxidation products and of known composition, some alloying elements are lost due to oxidation.
6. The crucible inside the furnace is cooled by __________
Explanation: The crucible in which the metal is placed is made of stronger materials that can resist the required heat, and the electric coil itself cooled by a water system so that it does not overheat or melt. The induction coil is cool to touch but the heat that builds is to be cooled.
7. Which of the following furnaces is the best to melt scrap?
b) Electric arc
Explanation: The induction furnace is commonly used to melt all grades of steels and iron as well as many non-ferrous alloys. As it can be used for re-melting of the metals, it is suitable for melting of scrap and reusing it.
8. The induction furnace can be used to melt as well as re-melting of the metal.
Explanation: The furnace is ideal for the melting and re-melting and alloying because of the high degree of control over the temperature and chemistry while the induction current provides good circulation of the molten metal.
9. Coreless Induction Furnace operates on ___________
b) Induction motor
Explanation: Coreless induction furnace consists of two types of coils; primary and secondary coil. The wall of the container forms the secondary winding and the iron core links the primary as well as the secondary coil. This is the principle of the transformer as well as induction furnace.
10. The induction furnace is replacing cupolas in the foundries.
Explanation: The induction furnace ranges from sizes of a small furnace to big one depending upon the amount of weight which is to be melted and the size of the organization. It is also replacing cupolas it emits lots of dust and pollutants and is less flexible in operations than induction furnace.
Sanfoundry Global Education & Learning Series – Foundry and Forging.
To practice MCQs on all areas of Foundry, here is complete set of 1000+ Multiple Choice Questions and Answers.