Scarica Basic metal processes (processi basici della lavorazione del metallo e più Slide in PDF di Inglese solo su Docsity! Module 5 Basic Metal Processes CONTENTS • STEELMAKING • BLAST FURNACE • THE STEELMAKING PROCESS • CASTING • DIE-CASTING • SAND CASTING AND STRAND CASTING • HOT AND COLD PROCESS • FORGING • EXTRUSION • POWDERED METAL PROCESSES • WELDING • BRAZING AND SOLDERING MARINO MARCO 2 MARINO MARCO 5 THE STEELMAKING PROCESS The steelmaking process revomes the excess carbon and impurities from the pig iron and adding other materials The L.D. use the oxygen to produced steel. Inside the converter, oxygen is blown onto the surface with a pipe, called lance The oxygen reacts with the impurities. Carbon is oxidized to carbon monoxide The steel is generally cast into ingots oxygen Pig iron MARINO MARCO 6 CASTING Casting is a method of shaping an object by pouring a liquid into a mould and letting it harden This process offers many advantages: - the most intricate shapes may be cast - some metal can only be cast to shape since they cannot be hot-worked - construction is simplified - this process is adaptable to mass production - extremely large, heavy object can be cast when it would be difficult to produce them in any other way The most common types of casting are die-casting, sand casting and continiuos or strand casting MARINO MARCO 7 DIE-CASTING Die-casting is the process of forging molten metal into the cavities of steel moulds called dies Common metal used in die-casting include zinc and alluminium The mould is sprayed with lubricant and closed. Molten metal is injected with high preassure Finally, the die is opened and the casting is ejected The preassure is maintained in the mould MARINO MARCO 10 FORGING Forging shaping metal by hammering or pressing Some example of forgeable materials are steel, nickel, aluminium and bronze The most common forging methods are: Hand forging Hammer forging Drop-hammer or impact-die forging MARINO MARCO 11 EXTRUSION Extrusion is the process of giving a specific shape by forcing it through a metal die The most commonly extruded materials include metals, plastics and rubber Extrusion can be hot or cold process In the hot porcess the temperature depends on the methd and the material is heated Cold extrusion is also called the Hooker process, the metal is forced through on orifice in a die Impact extrusion is similar to cold extrusiom MARINO MARCO 12 POWDERED METAL PROCESSES Powdered metallurgy is the process of powdered and pressing blending fine The powder metallurgy process has four basic steps - powder blending - compacting - sintering - secondary operations This process is very costly
