ch15 - 1 Chapter 15: Fundamentals of Metal Forming 15.1...

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 Chapter 15: Fundamentals of Metal Forming 15.1 Introduction s Deformation processes have been designed to exploit the plasticity of engineering materials s Plasticity is the ability of a material to flow as a solid without deterioration of properties s Deformation processes require a large amount of force s Processes include bulk flow, simple shearing, or compound bending States of Stress 2 15.2 Forming Processes: Independent Variables s Forming processes consist of independent and dependent variables s Independent variables are the aspects of the processes that the engineer or operator has direct control b Starting material b Starting geometry of the workpiece b Tool or die geometry b Lubrication b Starting temperature b Speed of operation b Amount of deformation Forming Operations Forming Operations 3 Forming Operations 15.3 Dependent Variables s Dependent variables are those that are determined by the independent variable selection b Force or power requirements b Material properties of the product b Exit or final temperature b Surface finish and precision b Nature of the material flow 15.4 Independent-Dependent Relationships s Independent variables- control is direct and immediate s Dependent variables- control is entirely indirect b Determined by the process b If a dependent variable needs to be controlled, the designer must select the proper independent variable that changes the dependent variable 4 Independent-Dependent Relationships s Information on the interdependence of independent and dependent variables can be learned in three ways b Experience b Experiment b Process modeling Figure 15-1 Schematic representation of a metalforming system showing independent variables, dependent variables, and the various means of linking the two. 15.5 Process Modeling s Simulations are created using finite element modeling s Models can predict how a material will respond to a rolling process, fill a forging die, flow through an extrusion die, or solidify in a casting s Heat treatments can be simulation s Costly trial and error development cycles can be eliminated 15.6 General Parameters s Material being deformed must be characterized b Strength or resistance for deformation b Conditions at different temperatures b Formability limits b Reaction to lubricants s Speed of deformation and its effects s Speed-sensitive materials- more energy is required to produce the same results 5 Stresses in Metal Forming s Stresses to plastically deform the metal are usually compressive b Examples: rolling, forging, extrusion s However, some forming processes b Stretch the metal ( tensile stresses) b Others bend the metal ( tensile and compressive) b Still others apply shear stresses Material Properties in Metal Forming s Desirable material properties: b Low yield strength and high ductility s These properties are affected by temperature : b Ductility increases and yield strength decreases when work temperature is raised s Other factors: b Strain rate and friction Bulk Deformation Processes...
View Full Document

Page1 / 18

ch15 - 1 Chapter 15: Fundamentals of Metal Forming 15.1...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online