Lab 1-Material Classification and Identification PDF

AIN SHAMS UNIVERSITY FACULTY OF ENGINEERING Sophomore Mechanical Eng. Program Structure and Properties of Materials (MDP 151) Lab 1-Material classification and identification Visual test: Objectives Identify different types of materials by various m...

AIN SHAMS UNIVERSITY FACULTY OF ENGINEERING Sophomore Mechanical Eng. Program Structure and Properties of Materials (MDP 151) Lab 1-Material classification and identification Visual test: Objectives Identify different types of materials by various means of Lab. (or shop) testing Introduction Solid materials have been conveniently grouped into basic classifications: metals, non-metals and composites. Metals can divided into two groups, ferrous (ie iron) and non-ferrous (ie copper). While non-metals can grouped into organic (like polymers) and inorganic (like. Ceramics). This scheme is based primarily on chemical makeup and atomic structure, and most materials fall into one distinct grouping or another, although there are some intermediates. In addition, there are two other groups of important engineering materials composites and semiconductors. As industry began to need more classes of materials, they were gradually developed; today many hundreds of these materials are in use. Without some means of reference or identification, work in the machine shop would be confusing. Therefore, this laboratory activity will introduce you several systems used for identifying different materials Background Many methods are used to identify a piece of metal. Identification is necessary when selecting a metal for use in fabrication or in determining its formability. Some common methods used for field identification are surface appearance, spark test, magnetic test, electrical and thermal and determination of density. Visual observation Some materials can be identified by visual observation of their finishes, touches, colors, texture, luster, and fracture appearance. Sometimes it is possible to identify metals by their surface appearance. Table 1 indicates the surface colors of some of the more common metals. A surface examination does not always provide enough information for identification but should give us enough information to place the metal into a class. The color of the metal and the distinctive marks left from manufacturing help in determining the identity of the metal. Cast iron and malleable iron usually show evidence of the sand mold. Low-carbon steel often shows, forging marks - and high-carbon steel shows either forging or rolling marks. Feeling the surface may provide another clue. Stainless steel is slightly rough in the unfinished state, and the surfaces of wrought iron, copper, brass, bronze, and nickel are smooth. Lead also is smooth but has a velvety appearance. When, the surface appearance of a metal does not give enough information to allow positive identification, other identification tests become necessary. At the end of Lab, you can answer the following questions: 1- Illustrate the general classification of Eng. Materials? 2- Explain using simple methods, how to identify (differentiate between) five samples from: copper, aluminum, steel, polymer and ceramic? 1 Table (1) surface colors of some of the more common metals Illustrate the general classification of Eng. Materials? 2 You are given pieces of different materials in solid stat and are asked to undergo the following testing. a. You are given some closed boxes with each a piece of an unknown material. By mere sensing (holding, balancing in the hand, etc.) try to identify the class of materials to which each one belongs. Write down your observations in the table below (Table 2). Sample # Shape, Color, Texture, Material* proposed by Material* proposed by Comments sensing visual observation Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample 7 Sample 8 Sample 9 Sample 10 Sample 11 Sample 12 *Material or materials group 3 Table 3 Sample # Shape Dimensions, cm Volume, Mass, Calculated Stand. , Material Comment (cm3) (gm) , (gm/cm3) (gm/cm3) 1 2 3 4 5 6 7 8 9 10 11 12 Explain using simple methods, how to identify (differentiate between) five samples from: copper, aluminum, steel, polymer and ceramic? 4