This set of Foundry Problems focuses on “Sections in the Foundry”.
1. _____________ is the most often used method for making of the complex shapes that are uneconomical to manufacture by other methods.
b) Machine Shop
c) Assembly Line
Explanation: In all the above mentioned ways, the basic function is the same that is the preparation of final products. But, the foundry is responsible for making up of castings which is often complex in shape and it cannot be made by manual methods. Usually, ferrous and non-ferrous alloys are employed for making castings.
2. Which of the following is the furnace used for melting in foundries?
b) Assembly Line
c) Pit Furnace
d) Electric Induction
Explanation: Out of all the furnaces, Cupola is largely used by the melting department in the foundry. Due to the varying sizes of the cupola the amount of metal melted is usually high and the materials required to charge the cupola are also widely available. Hence, the cupola is used in melting.
3. Castings of only ferrous materials can be made in foundries.
Explanation: The most common metals processed are aluminium and cast iron. However, other metals, such as bronze, brass, steel, magnesium, and zinc, are also used to produce castings in foundries. In this process, parts of desired shapes and sizes can be formed.
4. Which of the following is not included in scrap used for melting?
c) Defective castings
Explanation: All of the above mentioned types of materials are scraps from the earlier used materials except for billets. A billet is a form of cylindrical shaped raw materials which is melted and solidified to get to that shape after purification. Billets are externally prepared for ease of transportation and are not a scrap.
5. Shaking out is the easiest way to remove the sand from the castings after is it solidified.
Explanation: Shakeout frees the casting from the sand, which is attached to the metal runners and gates — the channels through which the molten metal traveled to reach the component itself. It is either done mechanically or manually.
6. The ____________ process is employed to remove gases.
Explanation: The Refining is done to remove deleterious gases and elements from the molten metal to avoid casting defects. The material is added during the melting process to bring the final chemistry within a specific range specified by industry and/or internal standards.
7. The pouring is accomplished by ______________ force.
Explanation: In a foundry, molten metal is poured into molds. Pouring can be accomplished with gravity, or it may be assisted with a vacuum or pressurized gas. Many modern foundries use robots or automatic pouring machines to pour molten metal. Traditionally, molds were poured by hand using ladles.
8. Which of the following plastic is not obtained from degating?
Explanation: The cores are made up of sand and are placed in the mould box to create cavities in the castings. Once the metal is poured and solidified, the cores are obtained in an amorphous form and cannot be withdrawn.
9. The heat treatment alters the properties of the materials and enhances them according to their functionality and material.
Explanation: Heat treating is a group of industrial and metalworking processes used to alter the physical, and sometimes chemical, properties of a material. The most common application is metallurgical aspects in the foundry and machine shop. Heat treatment techniques include annealing, case hardening, precipitation strengthening, tempering, and quenching.
10. The machining is the integral and last step in the foundry industry.
Explanation: The final and the integral step in the process of casting usually involves grinding, sanding, or machining the component in order to get the desired dimensional accuracies, physical shape, and surface finish. All of this is taken care by the machining shop.
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