Production Technology (IND 006) Lecture No. 7 Preparatory Year, Faculty of Engineering, Fayoum University Dr. Ahmed Salah Abou Taleb Lecturer, Industrial Engineering Dept., Faculty of Engineering, Fayoum University

Introduction

Metal Forming

Introduction Metal Forming Hot & Cold Working Spinning Forging Wire Drawing Tube Drawing Extrusion Deep Drawing Rolling

1- Hot & Cold Working Squeezing Stretching Bending

1- Hot & Cold Working

1- Hot & Cold Working Hot Working: The metal flow formed (worked) above its recrystallization temperature, so that the grains can reform as fast as they are distorted. Cold Working: The metal flow formed (worked) below its recrystallization temperature, so that the grains remain distorted.

1-1 Hot Working Hot Working Advantages: Hot Working Limitations: 1- Low cost. 2- Easier to work 3- Uses less energy or force. 4- Grain refinement from cast structure. 5- Pores may reduce in size or close completely during deformation. 6- Materials are left in the fully annealed condition. 7- Metal is ductile. Hot Working Limitations: 1- Poor surface finish and rough. 2- Low dimensional accuracy. 3- Low geometric accuracy. 4- Low in strength, and rigidity. 5- Oxidation of the workpiece. 6- Grain structure may vary throughout the metal. 7- Requires a heating unit (very expensive)

1-2 Cold Working Cold Working Advantages: 1- No heating required 2- Good surface finish. 3- Relatively high dimensional accuracy. 4- Relatively high geometrical accuracy. 5- Increase strength and rigidity. 6- No oxidation of surface. Cold Working Limitations: 1- Greater forces are required. 2- Heavier and more powerful equipment and stronger tooling are required. 3- Higher in equipment cost. 4- Metal is less ductile. 5- Undesirable residual stress may be produced.

2- Forging Is a manufacturing process involving the shaping of metal using localized compressive forces. Forging is often classified according to the temperature at which it is performed: cold, warm, or hot forging.   Forged parts can range in weight from less than a kilogram to 580 tons.

2- Forging

2- Forging

2- Forging

2- Forging

2- Forging

3- Rolling The slab is passed backwards and forwards between the work rolls of the mill. The gap between the mill rolls is gradually reduced for each pass. the thickness of the slab is reduced and its length is increased.

3- Rolling

4- Extrusion A hydraulic ram squeezing a billet of metal, preheated above the temperature of recrystillization, through a hole in the die is shaped to produce the required section. Materials: copper, brass alloys, aluminum and its alloys

5- Tube Drawing To size a tube by shrinking a large diameter tube into a smaller one, by drawing the tube through a die. In order to control the wall thickness and internal finish of the tube, a plug mandrel is used. The floating mandrel is drawn forward with the tube but cannot pass through the die.

6- Wire Drawing It is similar in principle to tube drawing but since a longer length of material is involved, the wire is pulled through the die by bulk block. The drawing wire may be coiled a coiler. Fine wire, as used for electrical conductors is produced on multiple head machines. As the wire become thinner it becomes longer.

7- Deep Drawing A blank of calculated diameter is placed on a die and held of it by a blank holder and bottom is pressed into the die by a punch and the walls are pulled in. Generally used for making cup shaped from the sheet blanks.

8- Spinning Is a process in which pressure and plastic flow is used to shape material. Spinning may be either hot or cold and is generally carried over spinning lathe. Metal is forced to flow over a rotating shape by pressure of blunt tool.