Page 355 - 04. Subyek Engineering Materials - Manufacturing, Engineering and Technology SI 6th Edition - Serope Kalpakjian, Stephen Schmid (2009)

Metal-Forging

Processes and

Equipment

I4.| Introduction 335
~ This chapter describes the fundamentals of forging and related processes, l4.2 Open-die Forging 337
including design and economic considerations. |4.3 Impression-die and
Closed-die Forging 339
' Open-die forging operations for producing simple shapes are discussed first,
|4.4 Various Forging
followed by impression-die and closed-die forging operations for producing Operations 343
more intricate shapes. I4.5 Forgeability of Metals;
° Various forging operations, such as heading, piercing, coining, swaging, and Forging Defects 348
I4.6 Die Design, Die Materials,
cold extrusion, are then introduced.
and Lubrication 349
° Factors involved in forging defects and die failures are explained. I4.7 Die-manufacturing
Methods and Die
° The economics of forging, as it relates to process selection, is also discussed.
Failures 35|
° The chapter ends with a review of the design of forged parts, die design and 14.8 Forging Machines 353
manufacturing, and selection of die materials and lubricants in forging I4.9 Economics of Forging 355
operations. EXAMPLE:
|4.I Calculation of Forging
Typical parts made by forging and related processes: Shafts, gears, bolts, turbine
Force in Upsetting 339
blades, hand tools, dies, and components for machinery, transportation, and
CASE STUDIES:
farm equipment.
I4.| Manufacture of a Stepped
Alternative processes: Casting, powder metallurgy, machining, and fabrication.
Pin by Heading and
Piercing Operations 345
l4.2 Suspension Components
I4.I Introduction for the Lotus Elise
Automobile
356
Forging is a basic process in which the workpiece is shaped by compressive forces
applied through various dies and tooling. One of the oldest and most important
metalworking operations, dating back at least to 4000 B.C., forging first was used
to make jewelry, coins, and various implements by hammering metal with tools
made of stone. Forged parts now include large rotors for turbines; gears; bolts and
rivets; cutlery (Fig. 14.1a); hand tools; numerous structural components for ma-
chinery, aircraft (Fig. 14.lb), and railroads; and a variety of other transportation
equipment.
Unlike rolling operations described in Chapter 13 that generally produce contin-
uous plates, sheets, strips, or various structural cross sections, forging operations pro-
duce discrete parts. Because the metal flow in a die and the material’s grain structure
can be controlled, forged parts have good strength and toughness, and are very reli-
able for highly stressed and critical applications (Fig. l4.2). Simple forging operations

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