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JNTU B.Tech III MECHANICAL WORKING OF METALS Previous Question Paper (January/February - 2023 - R18)

B.Tech | III | I | R18 | January/February - 2023

Answer PaperPaper Code: 155CDMaximum Marks: 75Time: 3 Hours

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

125 marks
a
How plane-stress conditions are defined?
2 marks

Answer

Plane-stress conditions are defined when one of the principal stresses is zero, typically occurring in thin sheets where the stress component normal to the surface is negligible compared to the in-plane stresses.

b
How the state of stress at a point is described?
3 marks

Answer

The state of stress at a point is described by a stress tensor consisting of nine components, represented as a 3x3 matrix. These include three normal stresses (σx, σy, σz) acting perpendicular to the faces and six shear stresses (τxy, τyx, τxz, τzx, τyz, τzy) acting parallel to the faces, which simplify to six independent components due to symmetry (τij = τji).

c
Explain the significance of true stress – strain parameters.
2 marks

Answer

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d
What do you mean by transverse plastic strains?
3 marks

Answer

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e
Distinguish between cold working and hot working.
2 marks

Answer

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f
What is the influence of temperature in metal working?
3 marks

Answer

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g
What is the significance of coefficient of friction?
2 marks

Answer

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h
What is controlled rolling?
3 marks

Answer

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i
What is patenting?
2 marks

Answer

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j
What is limit of drawability?
3 marks

Answer

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Part B

210 marks
a
Explain the advantages and limitations of Tresca criterion over Von Mises yield criterion.
5 marks

Answer

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b
Differentiate between elastic deformation and plastic deformation.
5 marks

Answer

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OR
310 marks
a
Consider the elemental cube whose faces represent the principal planes and draw maximum shear stress plane for the cube. Justify the answer in detail.
5 marks

Answer

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b
Write the mathematical expression for Von Mises yield criterion and explain in detail.
5 marks

Answer

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410 marks
a
Show that constancy of volume results in e1 + e2 + e3 = 0 and 1 + 2 + 3 = 0.
5 marks

Answer

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b
Why the relationship for conventional strain valid only for small strains but the relationship for true strain is valid for all strains?
5 marks

Answer

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OR
510 marks
a
Explain the octahedral shear stresses and strains.
4 marks

Answer

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b
Explain invariants of stress and strain.
3 marks

Answer

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c
Show that the equations for significant stress and strain reduce to the values for a tensile test.
3 marks

Answer

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610 marks
a
What would be the effect of section thickness ‘h’ on the forging load if the friction were reduced to zero?
5 marks

Answer

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b
Explain the effect of strain rate and microstructure on metal forming processes.
5 marks

Answer

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OR
710 marks
a
Show how a value of flow stress independent of friction can be obtained with the compression test using an extrapolation method.
5 marks

Answer

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b
Derive the expressions for flow stress and strain in plane-strain compression test.
5 marks

Answer

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810 marks
a
Explain the reasons for designing rolling mills with complex clusters of rolls.
5 marks

Answer

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b
Explain the basic requirements for a rolling lubricant.
5 marks

Answer

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OR
910 marks
a
What is planetary mill? Explain its characteristic features, advantages and limitations.
7 marks

Answer

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b
Explain how bars and shapes are produced.
3 marks

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1010 marks
a
Differentiate between piercing and extrusion processes.
3 marks

Answer

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b
An aluminium thin-walled tube (radius/thickness = 20) is closed at each end and pressurized to 1,000 psi to cause plastic deformation. Neglect the elastic strain and find the plastic strain in the circumferential direction of the tube. The plastic stress-strain curve is given by
σ = 25(ε)^0.25
, where stress is in ksi.
7 marks

Answer

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OR
1110 marks
a
Differentiate between tube sinking and tube drawing.
3 marks

Answer

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b
Explain the principle of wire drawing operation.
4 marks

Answer

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c
Differentiate between wire, rod and tube.
3 marks

Answer

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About this paper

This page contains the question paper of MECHANICAL WORKING OF METALS from JNTU for B.Tech MME-MMT III I, January/February - 2023, R18.

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