Posted in Metal Working Principles & Procedures

Standard Designations and Marking System of Metals

Knowledge of the standard designations of metals and the systems of marking metals is necessary so that you can select the proper material for a specific job. The standard designations discussed in this chapter are index numbers that are used to indicate the composition of the various metals. The two major systems used for iron and steel are those of the Society of Automotive Engineers (SAE) and the American and Steel Institute (AISI). The Aluminum Association method is used for aluminum. Other nonferrous metals we designated by the percentage and types of elements in their composition. FERROUS METAL DESIGNATIONS. You…

Posted in Metal Working Principles & Procedures

Properties of Materials

The physical properties of a metal or a plastic determine its behavior under stress, heat, and exposure to chemically active substances. In practical application, behavior of a material under these conditions determines its mechanical properties, indentation, and rusting. The mechanical properties of a material. therefore, are important considerations in selecting material for a specific job. The following information concerns metals. Plastics are discussed later in this chapter. Stress is the amount of internal force with which a material resists a change in shape. Strain is the deformation or change in shape that is caused by an applied load. Strength is…