JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III Year FABRICATION PROCESSES Previous Question Paper (January/February - 2023 - R16)
Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory, which carries 25 marks. In Part A, answer all questions. iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
Define volumetric shrinkage.
Answer
Volumetric shrinkage is the reduction in the volume of a cast metal as it cools from the molten state to room temperature. It occurs in three distinct stages: liquid contraction, solidification shrinkage during the phase change, and solid contraction as the casting cools to ambient temperature.
What is the purpose of riser in casting?
Answer
A riser, also known as a feeder, is a reservoir of molten metal provided in the casting mold to compensate for the volumetric shrinkage that occurs as the metal cools and solidifies. Its primary purposes are:
- To provide a source of liquid metal to the casting cavity to prevent shrinkage cavities or voids (porosity) as the liquid metal contracts during solidification.
- To act as a heat reservoir, ensuring that the metal in the riser remains molten longer than the casting itself, thereby allowing for effective feeding.
- To facilitate the escape of gases and air from the mold cavity, which helps in reducing casting defects.
Explain resistance welding.
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What is braze welding?
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What is recrystallization temperature?
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What is strain hardening?
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What fluids are used in hydrostatic extrusion?
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What is tube extrusion?
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Define open die forging.
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What is rolling? Write its applications.
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Part B
Sketch and explain the working of a crucible furnace. Give its applications.
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What are the elements of Gating System? Explain with sketches.
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Explain various stages in investment casting process using suitable sketches. Also, list the applications of the process.
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What are the casting defects? Explain the reasons for such defects and suggest suitable remedies.
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Explain types of welding joints with sketches. Also, give different welding positions.
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Describe different types of gas welding flames with sketches. Suggest suitable flame type for a given metal.
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Give the advantages and limitations of TIG welding over MIG welding.
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Discuss various destructive and non-destructive methods of testing weld quality.
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Distinguish between cold and hot working.
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A cup of height 10 mm, diameter 5 mm and corner radius 0.2 mm is to be made from sheet metal of 2.5 mm thickness. Find the suitable number of draws?
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The shear strength of cold rolled steel is 300 MPa. Determine the punch force required for making a blank of 120 mm diameter from a strip of 3 mm thickness of the above material. What is the theoretical and maximum punch force required?
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Sketch and explain wire drawing and tube drawing processes in detail. Give their applications and advantages.
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Distinguish between cold and hot extrusion processes.
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List out the advantages, disadvantages and limitations of extrusion.
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Explain with a neat sketch impact Extrusion process.
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What are the applications and limitations of extrusion process?
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Distinguish between drop and press forging process with reference to the process and products obtained.
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Classify forging defects and give the necessary remedies.
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Explain the rolling process in detail with the help of a sketch. What is Rolling Hill?
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Give the advantages of closed die forging over open die forging.
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