Page 336 - Manufacturing Engineering and Technology - Kalpakjian, Serope : Schmid, Steven R.
P. 336

Metal-Rolling

                                                   Processes and


                                                   Equipment







                                    ° This first chapter of Part III on the forming and shaping of metallic and non-
                                      metallic materials describes the rolling of metals, perhaps the most important
                             322      metal-forming operation based on volume of metals rolled.
                                    ° The chapter begins with a description of the flat-rolling process, analyzing the
                                                               q
                             327      force, tor ue and  P ower re uired in terms of relevant material and  P rocess
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                                      P arameters, as well as a review of defects and their causes in rolled roducts.
                                    ° Shape-rolling processes are then described, where Workpieces are passed through
               Force and Torque in    a series of shaped rolls.
               Flat-rolling  320
                                    ° Special rolling processes such as cross rolling, ring rolling, thread rolling, tube
                                      rolling, and tube piercing are also discussed.
                                    ° The chapter ends with a description of the characteristics of rolling mills and
                                      roll arrangements for specific products.
                                    Typical products made by various rolling processes: Plates for ships, bridges, struc-
                                    tures, machines; sheet metal for car bodies, aircraft fuselages, appliances, containers;
                                    foil for packaging; I-beams, railroad rails, architectural shapes, large rings, seamless
                                    pipe and tubing; bolts, screws, and threaded components.
                                    Alternative processes: Continuous casting, extrusion, drawing, machining of
                                    threaded components.



                                   l3.l    Introduction

                                   Rolling is the process of reducing the thickness or changing the cross section of a
                                   long workpiece by compressive forces applied through a set of rolls (Fig. 13.1).
                                   This process is similar to rolling dough with a rolling pin to reduce its thickness.
                                   Rolling, which accounts for about 90% of all metals produced by metalworking
                                   processes, was first developed in the late 1500s. Modern steelmaking practices and
                                   the production of various ferrous and nonferrous metals and alloys now generally
                                   involve combining continuous casting with rolling processes. This greatly improves
                                   productivity and lowers production costs, as described in Section 5.4. Nonmetallic
                                   materials also are rolled to reduce their thickness and enhance their properties.
                                   Typical applications are in the rolling of plastics, powder metals, ceramic slurry,
                                   and hot glass.

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