Contact Us - Tell A Friend - Make a Donation - Free-Ed.Net Home

Summary

Each metal or alloy has properties, qualities, or characteristics that make it desirable for a particular use. Undesirable qualities are toned down or compensated for by enhancing the desirable ones. This is done with alloys and metal processing.

Hardness is a metal's characteristic to resist penetration, cutting, or distortion. This quality can be enhanced by alloying, heat treatment, and cold working. Brittleness in a metal causes cracking or breaking under stress. Metal that can be shaped by hammering, rolling, or pressing is malleable. Ductility permits a metal to be drawn, bent, or twisted into various permanent shapes without breaking. This is a desirable quality in metal used for tubing or wire. Elasticity allows metal to return to its original shape when the force causing the change in shape is removed. Metal that conducts heat or electricity is conductive. Density is the mass per unit volume of a substance, and the preferred unit of volume expression is the cubic inch. Contraction and expansion are the qualities that describe a substance's reaction when heated or cooled. Strength is the measure of a metal's ability to hold loads or withstand an applied load. Toughness measures a metal's ability to withstand tearing, shearing, or stretching stresses. Stress, measured in pounds per square inch (psi), is the force or forces placed upon a metal, substance, or body. The different ways that stress forces can be applied are tension, compression, torsion, bending, and shear. Tension pulls or stretches a material, and resistance to tension is tensile strength. Compression describes a substance's decrease in volume under pressure. Torsion is the force that produces a twisting motion. Bending is a combination of tension and compression forces. Shear is a cutting force.

Copyright © 2005-09 SweetHaven Publishing Services
All rights reserved