A Practical Approach To Understanding Steels, Their Alloying, Heat Treatment And Surface Hardening.

Abstract

The greatest tonnage of engineering materials used in the world are steels. Therefore, it is most helpful, and in many cases mandatory, that those who either design, fabricate or maintain components constructed of steel have a practical understanding of how this family of materials functions. Steel is a very versatile material which can exhibit a wide range of both physical and mechanical characteristics. The diversity of steel is never more strikingly illustrated than the use of a file to round off a rough edge or a steel cutting tool to shape another piece of steel in some form of metal working equipment. These are two pieces of the same metal so different in properties that one, without damage to itself, will actually cut the other. The addition of various alloying elements to steel and how they affect the efficiency of thermal heat treatment, mechanical properties, dimensional stability, fatigue properties, wear and machinability will be discussed. In addition, all of the commonly used through section heat treating processes are described as they apply to steel and its alloys. The two major classes of surface hardening techniques, namely alterations to and no alternations of the surface chemistry, will be discussed as they apply to increasing hardness, improving wear and fatigue resistance and controlling dimensional stability of mechanical components.