1.
The type of weld represented by the shaded region in the figure is
Correct Answer
C. Fillet
Explanation
The shaded region in the figure represents a fillet weld. Fillet welds are commonly used to join two pieces of metal at right angles. They are characterized by a triangular-shaped cross-section and are often used in applications where strength and load-bearing capacity are not the primary concern. The fillet weld provides good resistance to shear forces and is commonly used in construction, fabrication, and automotive industries.
2.
The major difficulty during welding of aluminium is due to its
Correct Answer
A. High tendency of oxidation
Explanation
The major difficulty during welding of aluminium is due to its high tendency of oxidation. When aluminium is exposed to air, it quickly reacts with oxygen to form a thin layer of oxide on its surface. This oxide layer acts as a barrier, preventing proper bonding between the aluminium pieces being welded. In order to overcome this difficulty, special techniques and equipment are required to remove the oxide layer and create a clean surface for welding.
3.
In solid-state welding, the contamination layers between the surfaces to be welded are removed by
Correct Answer
B. Plastic deformation
Explanation
In solid-state welding, the contamination layers between the surfaces to be welded are removed by plastic deformation. This process involves applying pressure and heat to the surfaces being welded, causing them to deform and merge together. As the surfaces deform, any contaminants or oxide layers on the surfaces are pushed out and removed, ensuring a clean and strong bond between the materials. This method is effective in removing the contamination layers and promoting a successful weld.
4.
Which one of the following is a solid state joining process?
Correct Answer
C. Friction welding
Explanation
Friction welding is a solid state joining process because it involves the joining of two materials without the use of a liquid or molten state. In this process, the materials are rubbed together under pressure, generating heat through friction. This heat causes the materials to soften and bond together, creating a solid joint. Unlike other welding processes mentioned, such as gas tungsten arc welding, resistance spot welding, and submerged arc welding, friction welding does not involve the melting of the materials, making it a solid state joining process.
5.
It is desired to make a product having T-shaped cross-section from a rectangular aluminium block. Which one of the following process is expected to provide the highest strength of the product?
Correct Answer
C. Metal forming
Explanation
Metal forming is expected to provide the highest strength of the product. Metal forming processes such as forging and rolling involve shaping the metal while it is in a plastic state, which leads to the alignment of the metal grains and an increase in strength. Welding, casting, and machining processes do not typically involve plastic deformation of the metal and may result in lower strength compared to metal forming.
6.
The part of a gating system which regulates the rate of pouring of molten metal is
Correct Answer
C. choke
Explanation
The choke is the part of a gating system that regulates the rate of pouring of molten metal. It acts as a restriction in the flow, controlling the flow rate and preventing excessive pouring. By adjusting the size or shape of the choke, the flow rate can be controlled to ensure a consistent and controlled pour of the molten metal.
7.
The welding process which uses a blanket of fusible granular flux is
Correct Answer
B. Submerged arc welding
Explanation
Submerged arc welding is the welding process that uses a blanket of fusible granular flux. In this process, a layer of flux covers the weld area, preventing atmospheric contamination and providing protection from the heat generated during welding. The flux also acts as a deoxidizer, removing impurities from the weld. The arc is created between a continuously fed electrode and the workpiece, which is submerged in the flux. This process is commonly used for welding thick materials and in applications where high productivity is required.
8.
In a linear arc welding process, the heat input per unit length is inversely proportional to
Correct Answer
C. Welding speed
Explanation
In a linear arc welding process, the heat input per unit length is inversely proportional to the welding speed. This means that as the welding speed increases, the heat input per unit length decreases. This is because a higher welding speed leads to a shorter arc length and less time for the heat to be transferred to the workpiece. Therefore, the faster the welding speed, the less heat is inputted per unit length of the weld.
9.
In full mould (cavity-less) casting process, the pattern is made of
Correct Answer
A. Expanded polystyrene
Explanation
In full mould (cavity-less) casting process, the pattern is made of expanded polystyrene. This material is commonly used in this process because it can be easily shaped and molded into complex designs. Expanded polystyrene patterns are lightweight, durable, and have good dimensional stability. They can withstand the high temperatures and pressures of the casting process without deforming or breaking. Additionally, expanded polystyrene patterns can be easily removed from the mold after casting, leaving behind a precise and accurate final product.
10.
The hot tearing in a metal casting is due to
Correct Answer
C. Wide range of solidification temperature
Explanation
Hot tearing in a metal casting is caused by a wide range of solidification temperature. When the solidification temperature range is broad, different parts of the casting solidify at different rates, leading to internal stresses and the formation of cracks. This phenomenon is known as hot tearing. Factors such as high fluidity, high melt temperature, and low coefficient of thermal expansion may affect the casting process but are not directly responsible for hot tearing.