Metal Identification

Most Valuable Metal

metalidentification — Mon, 21 May 2007 05:24:18 +0000

Most valuable metal A valuable metal is a rare metallic chemical element of high economic value. In metal identification , the valuable metals are less unthinking than most elements, have high shine, and have higher melting points than other metals. Historically, valuable metals were important as currency, but are now regarded mainly as investment and industrial possessions. Gold, silver, platinum and palladium each have an ISO 4217 currency code. Most known valuable metals are gold and silver. While both have industrial uses, they are better known for their uses in art, jeweler, and coinage. Other precious metals contain the Platinum group metals: ruthenium, rhodium, palladium, osmium, iridium and platinum, of which platinum is the most widely traded. (more…)

Metal Properties

metalidentification — Mon, 21 May 2007 05:22:27 +0000

Metal properties Chemical properties The largest part metals in metal identification are chemically reactive, reacting with oxygen in the air to form oxides over shifting timescales (for illustration iron rusts over years and potassium burns in seconds). The alkali metals react quickest followed by the alkaline earth metals, found in the leftmost two groups of the periodic table. The transition metals take much longer to oxidize (such as iron, copper, zinc, nickel). Others, like palladium, platinum and gold, do not respond with the atmosphere at all. Some metals form a wall layer of oxide on their surface which cannot be penetrated by further oxygen molecules and thus retain their shiny look and good conductivity for many decades (like aluminum, some steels, and titanium). The oxides of metals are basic (as opposed to those of nonmetals, which are acidic), although this may be considered a rule of thumb, rather than a fact. Painting or anodizing metals are good ways to prevent their corrosion. On the other hand, a more reactive metal in the electrochemical series must be chosen for coating, especially when chipping of the coating is anticipated. Water and the two metals form an electrochemical cell, and if the coating is less reactive than the outer surface, the coating actually promotes corrosion. (more…)

Classification of Metal

metalidentification — Mon, 21 May 2007 05:21:15 +0000

Classes of metals Ferrous and non-ferrous metals Other way of classifying metals is by their content, and one common splitting up is into ferrous metals and non-ferrous metals. The word ferrous is originated from the Latin “Ferrum” which means “containing iron”, thus ferrous metals contain iron and non ferrous metals do not. Ferrous metals may be clean iron, like wrought iron, or they may be alloys of iron and other elements. In metal identification the Steel, being an alloy of iron and carbon, would therefore be a ferrous metal. Ferrous metals are frequently magnetic, but this property is not in and of itself sufficient to classify a metal as ferrous or non-ferrous. Austenitic stainless steel, a ferrous metal, is non-magnetic, while cobalt is magnetic but non-ferrous. (more…)

Metal Fabrication

metalidentification — Mon, 21 May 2007 05:19:56 +0000

Metal Trade and Production In Metal Trade and Production, metallurgy is focusing with the production of metallic works and metal identification for use in consumer or engineering products. This involves the production of alloys, the shaping, the heat treatment and the surface treatment of the product. The job of the metallurgist is to attain design criteria specified by the mechanical engineer, such as cost, weight, strength, toughness, hardness, corrosion and weariness resistance, and presentation in temperature extremes. Widespread engineering metals are aluminums, chromium, copper, iron, magnesium, nickel, titanium and zinc. These are most often used as alloys. Much attempt has been placed on discerning one, on important alloy system, that of purified iron, which has carbon dissolved in it, better known as steel. Normal steel is used in low cost, high strength applications where weight and corrosion are not a problem. Cast irons, including flexible iron are also part of this system. Stainless steel or galvanized steel are used where resistance to corrosion is important. Aluminium alloys and magnesium alloys are used for applications where strength and weightlessness are required. A nickel-based alloy such as reproduction is used in highly corrosive environments and for non-magnetic applications. The nickel-based is used in high temperature applications such as turbochargers, pressure vessels, and heat exchangers. (more…)

Iron Based Metal

metalidentification — Mon, 21 May 2007 05:18:45 +0000

Iron based metal Cast iron Cast iron usually refers to grey cast iron, but identifies a large group of ferrous alloys, which harden with a eutectic. In metal identification iron accounts for more than 95%, while the main alloy elements are carbon and silicon. The quantity of carbon in cast irons is the range 2.1 - 4%, as ferrous alloys with less are denoted carbon steel by definition. Cast irons be full of appreciable amounts of silicon, normally 1 - 3%, and consequently these alloys should be considered ternary Fe-C-Si alloys. Even though this, the principles of cast iron solidification are understood from the binary iron-carbon phase diagram, where the eutectic point lies at 1154 °C and 4.3 wt% carbon. Since cast iron has nearly this composition, its melting temperature of 1150 to 1200 °C is about 300 degrees lower than the melting point of pure iron. Cast iron tends to be brittle, unless the name of the particular alloy suggests otherwise. The color of a fracture surface can be used in metal identification to identify an alloy: carbide impurities allow cracks to pass straight through, follow-on in a smooth, “white” surface, while graphite flakes deflect a passing crack and initiate countless new cracks as the material breaks, resulting in a rough surface that appears grey. By means of its low melting point, good fluidity, castability, excellent machinability and wear resistance, cast irons have become an engineering substance with a wide range of applications, including pipes, machine and car parts. (more…)