1.
Presence of which material in aluminium alloy provides ductility to the alloy?
Correct Answer
C. Copper
Explanation
Copper is the material that provides ductility to aluminium alloy. Ductility refers to the ability of a material to be stretched or deformed without breaking. Copper is known for its high ductility, and when added to aluminium alloy, it enhances its ability to withstand deformation without fracturing. This makes the alloy more malleable and allows it to be easily shaped or formed into various structures or products. Therefore, the presence of copper in aluminium alloy contributes to its ductility.
2.
Which furnace is not used for heating aluminium alloys?
Correct Answer
A. Electric arc furnace
Explanation
Electric arc furnaces are not commonly used for heating aluminium alloys. These furnaces are primarily used for melting and refining steel and other metals. Aluminium alloys are typically heated using other types of furnaces such as pot furnaces, induction heating furnaces, or crucible furnaces, which are better suited for the specific requirements of heating aluminium alloys. Therefore, the correct answer is Electric arc furnace.
3.
Which of the following is not a purpose of fluxing and flushing the aluminium alloys?
Correct Answer
B. Removal of dissolved oxygen
Explanation
Fluxing and flushing of aluminium alloys is done to remove impurities and contaminants from the melt. Dissolved hydrogen can cause porosity in the alloy, so it needs to be removed. Dross, which is a layer of impurities on the surface of the melt, needs to be separated and entrapped to ensure a cleaner alloy. Dissolved oxygen, however, is not a purpose of fluxing and flushing. Oxygen can react with the alloy and cause oxidation, but it is typically removed through other processes such as degassing.
4.
What is the silicon composition present in an LM-17 cast aluminium alloy?
Correct Answer
D. 11.5%
Explanation
The correct answer is 11.5%. In an LM-17 cast aluminium alloy, the silicon composition is 11.5%. Silicon is commonly added to aluminium alloys to improve their strength, hardness, and corrosion resistance. It also helps in reducing shrinkage during solidification and improves the fluidity of the molten metal. The specific silicon composition in an alloy depends on the desired properties and the intended application of the alloy.
5.
Which gas is not used for fluxing and flushing in aluminium alloys?
Correct Answer
D. Oxygen
Explanation
Oxygen is not used for fluxing and flushing in aluminium alloys because it can react with the aluminium, causing oxidation and potentially compromising the quality of the alloy. Fluxing and flushing processes are used to remove impurities and create a clean surface for further processing, and gases like argon, chlorine, and nitrogen are commonly used for these purposes. Oxygen, on the other hand, can introduce unwanted reactions and should be avoided in these processes.
6.
Up to what length can the surface finish be achieved by green sand in aluminium alloys?
Correct Answer
B. 650 micro inch
Explanation
Green sand is a type of molding sand that is commonly used in the foundry industry for casting aluminum alloys. The surface finish refers to the smoothness and texture of the surface of the cast part. In this case, the correct answer is 650 micro inch, which means that green sand can achieve a surface finish of up to 650 micro inches in aluminum alloys. This indicates a relatively smooth and fine surface texture for the cast part.
7.
Which of the given metals is not counted among late additions in aluminium alloys?
Correct Answer
C. Manganese
Explanation
Manganese is not counted among late additions in aluminium alloys because it is typically added in the early stages of alloying to improve strength and corrosion resistance. Late additions in aluminium alloys usually refer to elements like boron and sodium, which are added in the final stages of alloying to modify the microstructure and enhance certain properties. Titanium can also be considered a late addition in some cases, as it is added to improve grain refinement and mechanical properties.
8.
Aluminium alloys are not susceptible to which of the following?
Correct Answer
A. Macro shrinkage
Explanation
Aluminium alloys are not susceptible to macro shrinkage. Macro shrinkage refers to the formation of visible voids or cavities in the metal due to improper cooling or solidification. Aluminium alloys have a high fluidity and low solidification shrinkage, which makes them less prone to macro shrinkage compared to other metals.
9.
A runner is located away from the:
Correct Answer
B. Drag
10.
Pouring basins are used for:
Correct Answer
A. Reducing vortex formation.
Explanation
Pouring basins are used to reduce vortex formation. When pouring liquid into a container, a vortex can form due to the circular motion of the liquid. This vortex can lead to splashing and uneven distribution of the liquid. Pouring basins are designed to minimize this vortex formation by providing a wider and shallower area for the liquid to enter. This helps to prevent splashing and ensures a more even and controlled pour. Therefore, pouring basins are specifically used to reduce vortex formation.