Why the cupping test may not predict well the formability of sheet metals in actual forming processes? Cupping test uses square or rectangular specimens only. Strain in some forming operations is not axi-symmetric. Cupping test is mainly for compression Stress is rarely uni-directional in sheet metal forming.

Why the cupping test may not predict well the formability of sheet metals in actual forming processes? Cupping test uses square or rectangular specimens only. Strain in some forming operations is not axi-symmetric. Cupping test is mainly for compression Stress is rarely uni-directional in sheet metal forming.

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

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Questions: 1. Two thick slabs of 300mm each, the first one is used in cold rolling where u=0.08 while the second is used in cold rolling where u-0.5. The mill roll diameter in each case is the same as 600mm. Determine the max draft (reduction) in both cases. Discuss the wide difference in results. = 2. A tensile specimen of the metal of 100 mm is length stretched to a length 157 mm during the rolling process. If the metal has a flow curve with parameters: K = 850 MPa and strain hardening exponent n = 0.30. Determine the average flow stress that the metal has been subjected to during the deformation.
3) A direct extrusion process is used to reduce a cylindrical part that has a diameter of 5 inch and is 10 inch long to a cylinder with 2 inch diameter. The die angle is 90°. The cylinder material has a strength coefficient of 10 ksi and strain hardening exponent Of 0.15. Determine a. Extrusion strain b. Ram force
3XPL@!N THE PROCESS @ND PROVIDE EXAMPLES FORMING OPERATIONS 1. Forging is mechanically working or deforming a single piece of a usually hot metal; this may be accomplished by the application of successive blows or by continuous squeezing. 2. Rolling, the most widely used deformation process, consists of passing a piece of metal between two rolls; a reduction in thickness results from compressive stresses exerted by the rolls. 3. Extrusion, a bar of metal is forced through a die orifice by a compressive force that is applied to a ram; the extruded piece that emerges has the desired shape and a reduced cross-sectional area. 4. Drawing is the pulling of a metal piece through a die having a tapered bore by means of a tensile force that is applied on the exit side.
QUESTION 3 Extrusion and drawing have numerous application in manufacturing continuous as well as discrete products from a wide variety of metals and alloys. There are three types of extrusion. Please describe and draw the schematic illustration to represent each of them. Question 4 Selection of die in forging process is very important in order to control the quality of the product. List four general requirements for die material.
Both extrusion and bar drawing processes can be used to reduce the cross section. What can be the basic differences between extrusion and bar drawing processes? Also discuss briefly why must the drawing stress never exceed the yield strength of the work metal?
(c) A flat rolling operation is being carried out where the roll radius is 200 mm and the roll rotates at 100 rpm. The workpiece material is annealed low carbon steel with 200 mm wide and 10 mm thickness. The strength coefficient and the strain hardening of the carbon steel are 530 MPa and 0.26, respectively. The coefficient of friction is 0.2. (i) Caicurae tne roll force and torque if the workpiece is rolled to a thickness of 4 mm. (ii) Calculate the maximum possible draft and evaluate how friction effect the thickness of the rolled workpiece.
Homework: In hot rolling process, the following data was collected: N=20rpm, R=20cm, to=40mm, tF35mm, C=415MPA, m=0.02, w-60cm one pass rolling. Find Froll, T and Power.
Which of the following is true about open die forging process? O Forged pieces have accurate dimensions therefore there is usually no need for additional finishing operations such as heat treatment or machining. O Forged pieces have outstanding grain structure and the best combination of mechanical properties. O Forging is carried out at temperature above re-crystallization temperature Forged pieces are small in size since the forging process is incapable of doing large components such as turbine shafts.
b Discuss the qualitative changes of burst and collapse resistances when the casing string is become under tension or compression load. c Explain how casing design problems depend heavily on stress analysis techniques, rock mechanics and drilling and production conditions.
3. Write any four major forging defects and solution for those defects.
Explain steps of extrusion process in forming process?
5) A steel specimen of rectangular cross section with 120 mm width, 180 mm thickness and 90 mm height was upset at room temperature by open-die forging to a height of 55 mm. If the strength coefficient and strain hardening exponent of this material were 1015 MPa and 0.17 respectively, the coefficient of friction is 0.2, and assuming that the thickness would not change during forging; determine the required upsetting force at the end of stroke.