金属的挤出及拉拔Ch15.ppt

Chapter 15 Direct-Extrusion Extrusions and Products Made from Extrusions Types of Extrusion Process Variables in Direct Extrusion Extrusion Force Types of Metal Flow in Extrusion with Square Dies Extrusion Temperature Ranges Extrusion-Die Configurations Extrusion in Creation of Intricate Parts Design of Exruded Cross-Sections Extrusion of Heat Sinks Cold Extrusion Examples Cold-Extruded Spark Plug Impact-Extrusion Process Impact Extrusion Chevron Cracking 9-MN (1000-ton) Hydraulic-Extrusion Press Process Variables in Wire Drawing Tube-Drawing Operations Drawing Dies Extruded Channel on a Draw Bench Multistage Wire-drawing Machine Manufacturing, Engineering Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid. ISBN 0-13-148965-8. ? 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved. Extrusion and Drawing of Metals Figure 15.1 Schematic illustration of the direct-extrusion process. Figure 15.2 Extrusions and examples of products made by sectioning off extrusions. Source: Courtesy of Kaiser Aluminum. Figure 15.3 Types of extrusion: (a) indirect; (b) hydrostatic; (c) lateral; Figure 15.4 Process variables in direct extrusion. The die angle, reduction in cross-section, extrusion speed, billet temperature, and lubrication all affect the extrusion pressure. Figure 15.5 Extrusion constant k for various metals at different temperatures. Source: After P. Loewenstein Figure 15.6 Types of metal flow in extruding with square dies. (a) Flow pattern obtained at low friction or in indirect extrusion. (b) Pattern obtained with high friction at the billet-chamber interfaces. (c) Pattern obtained at high friction or with coiling of the outer regions of the billet in the chamber. This type of pattern, observed in metals whose strength increases rapidly with decreasing temperature, leads to a defect known as pipe (or extrusion) defect. Figure 15.7 Typical extrusion-die configurations: (a) die for nonferrous metals; (