Materials

ferrous metallurgy

involves processes and alloys based on iron

non ferrous metallurgy

involves processes based on their materials

wrought iron

iron alloy with a very loww carbon content, in comparison to steel, and has fibrous inclusions ( slag )

Ferrous Alloys

iron is the principal constituent, include steel or cast iron

copper

latin cuprum (Cu) rank next to iron in importance and wide range of application good heat and electrical conductivity whitish with bluish cast

magnesium

lightest engineering material available combination of low density and good mechanical strength has made it one of the most specified materials in aircraft, space, portable power tools, luggage, and similar applications as conpeting with aluminum alloys

Non ferrous Metals

low permeability the pure metals are rarely used as structural materials as they lack mechanical strength they are used where their special properties such corrosion resistance, electrical conductivity and thermal conductivity are required they can be fabricated with ease, high relatively low density, and high electrical and thermal conductivities

Three classes of stainless steels

martensitic ferritic austenitic

Forging

mechanically working or deforming a single piece of a normally hot metals classified as either closed or open die

Alloys

mixture of two or more metals or non-metals together having good mechanical stregth, low temperature coefficient of resistance

carbon

most common alloying material for iron

Grey Cast Iron

named after greyfractured surface, which occurs because the graphitic flakes deflect a passing crack and initiate countless new cracks as the material breaks

White Cast Iron

named after its white surface when fractured, due to its carbide impurities which allow cracks to pass straight through

Iron

pig iron cast iron - white cast iron - grey cast iron wrought iron

Metals

polycrystalline bodies which are having number of differentially oriented fine crystals

miscellaneous

powder metallurgy welding

cold working

produced an increase in strength with the attendant decrease in ductility

casting

sand die investment lost foam continuous

Non Ferrous alloys

steel and other ferrous alloys are consumed in exceedingly large qunatities because they have such a wide range of mechanical properties may be fabricated with ease, and are economical to produce

fabrication of metals

techniques are normally preceded by refining, alloying, and often heat-treating processes that produce alloys with the desired characteristics

Non ferrous alloys distinct limitations

(1) a relatively high density (2) a comparatively low electrical conductivity (3) inherent susceptibility to corrosion in some common environments

Ferrous alloys widespread use is accounted by for three factors

(1) iron-containing compounds exist in abundant quantitis within the earth's crust (2) metallic iron and steel alloys may be produced by using relatively economical extraction, refining, alloying, and fabrication techniques (3) ferrous alloys are extremely versatile, in that they maybbe tailored to have a wide range of mechanical and physical properties

stainless steel

(inox steel) is a steel alloy with a minimum of 10.5 or 11% chromium content by mass. does not corode, rust, or stain with water as ordinary steel does Alloy: are highly resistant to corrosion (rusting) in a variety of environments, especially the ambient atmosphere predominant alloying element is chromium a concentration of atleast 11wt% Cr is required

Aluminum

Most important non ferrous metal. outstanding physical properties it is suitable for all machining, casting and forming operations low density and ability to resist corrosion; good conductivity

extrusion

a bar metal is forced through a die orifice by a compressive force that is applied to a ram

closed die

a force is brought to bear on two or more die halves having the finished shape such that the metal is deformed in the cavity between them

steel

alloy consist mostly iron and has carbon content between 0.2% and 2.1% by mass. Alloy: are iron-carbon alloys that may contain appreciable concentrations of otger alloying elements

zinc

an inexpensive material with modorate strenght chemically similar to magnesium more ductile but not as strong bluish white most commonly used to extend the life of other materials such as steel, rubber and plastic, and wood

metals

are alloyed to enchance their properties

major metals

are solid state at normal temperature

Forging operations

are those in which the shape of a metal piece is changed by plastic deformation the deformation must be induced by an external force or stress, the magnitude of which must exceed the yield strength of the materials

Medium-carbon steel

carbon concentration between about 0.25 and 0.60 wt% these alloys be heat treated by austenitizing, quenching, and then tempering to improve their mechanical properties most often utelized in the tempered condition these heat treated alloys are stronger than low carbon steel

High-Carbon steel

carbon contents of 0.60 to 1.4 wt% are the hardest, strongest, and yet least ductile of the carbon steels they are almost always used in a hardened and tempered condition and as such, are especially wear resistant and capable of holding a sharp cutting edge usually contains chronium, vanadium, tungsten, and molybdenum

high speed steel

commonly used in tool bits and cutting tools can withstand higher temperatures without losing its hardness

Copper alloys

coppers (minimum 99.3% Cu) high coppers (99.3-96% Cu) Brasses ( Cu-Zn alloys with 5-40% Zn) bronze (mainly Cu-Sn alloy)

Cast iron

derived from iron

forming operations

forging rolling extrusion drawing

metals

having high thermal and conductivity

Ferrous metals

having iron as common element strongest materials available and are used for applications where high strength is required at relativelyvlow cost and where weight is not a primary importance

ferrous materials

having very high permeability which makes these materials suitable for construction of core of electrical machines

classifications of fabrication techniques

includes various metal-forming methods casting powder metallurgy welding and machining

Metallurgy

technology of metals the way in which science is applied to the production of metals the engineering of metal components for usage in products for consumers and manufacturers a domain of material science and engineering that studies the physical and chemical behavior of metallic elements, their intermetallic compounds, and their mixture, which are called alloys

pig iron

the intermediate product of smelting iron ore with a high-carbon fuel such as coke, usually with limestone as a flux

rolling

the most widely used deformation process consists of passing a piece of metal between two rolls reduction in thickness results from compressive stresses exerted by the rolls

Drawing

the pulling of metal piece through a die having a tapered bore by means of a tensile force that is applied on the exit side

Low-Carbon steel

these generally contain less than about 0.25 wt% C and are unresponsive to heat treatments intender to form martensite; strengthening is accomplised by cold work as a consequence, these alloy are relatively soft and weak but have outstanding ductility and toughness; in addition, they are machinable, weldable, and of all steels, are the least expensive to produce

Tin

too weak to be used alone for most mechanical applications it is often alloyed with elements such as copper, antimony, lead, aluminum and zinc to improve mechanicalor physical properties commonly used as a coating

open die

two dies having simple geometric shapes are employed, normally on large work pieces

titanium

used for corrosive environment or applications of light weight, high strength and nonmagnetic properties it has good high temperature stregth as compared with other light metals

Lead

versitile material due to special properties of high atomic weight and density, softness, ductility, low stregth, low melting point, corrosion resistance and ability to lubricate. toxicity is one of the chief disadvantage

hot working

when deformation is achieved at a temperature above that at which recrystallization occurs