Page 399 - 04. Subyek Engineering Materials - Manufacturing, Engineering and Technology SI 6th Edition - Serope Kalpakjian, Stephen Schmid (2009)

Qualitative Problems 379

BIBLIOGRAPHY

Altan, T., Ngaile, G., and Shen, G. (eds.), Cold and Hot Lange, K. (ed.), Handbook of Metal Forming, McGraw-Hill,
Forging: Fundamentals and Applications, ASM 1985.
International, 2004. Michaeli, W, Extrusion Dies, 2nd ed., Hanser, 1992.
ASM Handbook, Vol. 14A: Metalworking: Bulk Forming, Nonferrous Wire Handbook, 2 vols. The Wire Association
ASM International, 2005. International, Inc., 1977 and 1981.
Blazynski, TZ., Plasticity and Modern Metal-forming Saha, P., Aluminum Extrusion Technology, ASM Inter-
Technology, Elsevier, 1989. national, 2000.
Hosford, WF., and Caddell, R.M., Metal Forming: Sheppard, T., Extrusion of Aluminum Alloys, Chapman SC
Mechanics and Metallurgy, 3rd ed., Cambridge, 2007. Hall, 1997.
Inoue, N., and Nishihara, M. (eds.), Hydrostatic Extrusion: Tschaetch, H., Metal Forming Practice: Processes, Machines,
Theory and Applications, Elsevier, 1985. Tools, Springer, 2007.

REVIEW QUESTIONS

l5.l. How does extrusion differ from rolling and forging? l5.9. Describe the difference between direct and reverse
extrusion.
l5.2. Explain the difference between extrusion and drawing.
|5.3. What is a spider die? What is it used for? l5.I0. What is land? What is its function in a die?
|5.4. Why are wires sometimes drawn in bundles? l5.l I. How are tubes extruded? Can they also be drawn?
Explain.
I5.5. What is a dead-metal zone?
l5.|2. It is possible to extrude straight gears; can helical
l5.6. Define the terms (a) cladding, (b) dummy block,
gears also be extruded? Explain.
(c) shear dies, (d) skull, and (e) canning.
I5.l3. What is the difference between piping and bambooing?
l5.7. Why is glass a good lubricant in hot extrusion?
I5.8. What types of defects may occur in (a) extrusion and
(b) drawing?

QUALITATIVE PROBLEMS

I5.I4. Explain why extrusion is a batch, or semicontinu- l5.23. In which applications could you use the type of
ous, process. Do you think it can be made into a continuous impact-extruded parts shown in Fig. 15.16?
process? Explain. l5.24. Can spur gears be made by (a) drawing and (b) extru-
l5.|5. Explain why cold extrusion is an important manu- sion? Can helical gears? Explain.
facturing process. l5.25. How would you prepare the end of a wire in order to
I5.|6. What is the function of a stripper plate in impact be able to feed it through a die so that a drawing operation
extrusion? can commence?
|5.l 7. Explain the different ways by which changing the die l5.26. What is the purpose of a dummy block in extrusion?
angle affects the extrusion process. Explain.
l5.|8. Glass is a good lubricant in hot extrusion. Would l5.27. Describe your observations concerning Fig. 15.9.
you use glass for impression-die forging also? Explain. I5.28. Occasionally, steel wire drawing will take place
|5.l9. How would you go about avoiding center-cracking within a sheath of a soft metal, such as copper or lead. What
defects in extrusion? Explain why your methods would be is the purpose of this sheath?
effective. |5.29. Explain the advantages of bundle drawing.
l5.20. Table 15.1 gives temperature ranges for extruding l5.30. Under what circumstances would backwards extru-
various metals. Describe the possible consequences of extrud- sion be preferable to direct extrusion?
ing at a temperature (a) below and (b) above these ranges.
|5.3l. Why is lubrication detrimental in extrusion with a
I5.2l. Will the force in direct extrusion vary as the billet porthole die?
becomes shorter? If so, why?
l5.32. Describe the purpose of a container liner in direct
l5.22. Comment on the significance of grain-flow patterns, extrusion, as shown in Fig. 15.1.
such as those shown in Fig. 15.6.