Question

When metal foundry products are cleaned by shot blasting, heat is generated by friction. Nitrogen is used for:
A. Providing an inert atmosphere
B. Cooling the blast chamber
C. Reducing friction
D. Displacing hot air

Answer 1

Hint: The two atoms in nitrogen are attached through a triple bond between. This makes it strong. In order to break such a strong bond, tremendous energy is needed, so nitrogen can be used to provide an inert atmosphere.

Complete step by step answer:
Shot Blasting is a surface treatment, to clean, peen or polish metal by means of high velocity steel abrasive. Shot blasting is an effective means through which it is possible to obtain excellent cleaning and surface. Shot blasting is commonly used for cleaning of iron, steel forgings, etc. Shot blasting is used in almost every industry that uses metal, which include construction, foundry, aerospace, automotive, shipbuilding, rail etc. The major technologies used in shot blasting are wheel blasting and air blasting.
Factory that produces metal castings is a foundry. Here, metals are cast into different shapes by melting them into a liquid, pouring the metal into a mould, and removing the mould material after the solidification of metal as it cools. The most common metals processed by shot Blasting are aluminium and cast iron.
The main function of a shot blasting machine is the movement of projectiles to hit the metal surface to prevent contamination of the surface and to improve strength of metal. Blasting machines can perform many tasks like cleaning, removal of rust, producing uniform cosmetic finish, mechanical function texturing, adhesion texturing, casting of die casting etc. Blasting machines can also provide protection of metal from corrosion that can occur depending on the environmental and working conditions. It can leave the substrate dry and clean by preparing surfaces for recoating.
A large amount of heat is generated during this process by friction. Here, nitrogen is commonly used as inert gas to create an inert atmosphere because it consists of strong triple bonds. It needs a lot of energy to break and participate in a reaction.

So, the correct answer is Option A.

Note: Sandblasting and shot blasting, both are the processes used for mechanical surface cleaning. Many industries who use this method. The differences in both the processes are in principle and application types. Metallurgy is the process of extraction of metal from its ore.