1. Teknologi Dan Rekayasa
KIND OF METALS

2. A BOUT OF METAL
I can define the terms associated with metal and metal fabrication.
I can explain metal classification.
I can list the major characteristics of ferrous metal, nonferrous metal and alloys
I can identify types of metals by the way of the spark test.
I can identify the different ways marking and cutting metal.
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3. PROPRIETIES 1. Solid at room temperature.
Most metals are solid at room temperatures (one notableexception is mercury).
Solid means having a definite shape and volume.
2.  Opaque
Metal will not permit light to pass through it.
Even very thin sheets of metal cannot be penetrated
by ordinary light.
3.  Conductor of heat and electricity.
All metals are conductors because they have electrons, which are free to move about.
This property of metals is very important and
widely used.
(Gold, silver, aluminum and copper are very good conductors.)
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4. PROPRIETIES 4. Luster All metal seems to reflect light when polished.
5.  Crystalline structure
Upon examination under a microscope, a metal is found to be made up of small grains.
These grains (crystals) vary in shape and size.
The arrangement of the atom (small particles within the grains) determine the shape of the crystalline structure.
6.  Expansion and contraction
Metal expand when heated and contract when cooled. This is due to the spacing of the atoms within each grain of metal.
7.  Hardness
This is the ability of a material to resist indentation, penetration, abrasion and scratching. Metals vary in hardness. Carbon content and application of heat will affect hardness.
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5. PROPRIETIES 8. Magnetism This is important property in metals.
Metals that are attracted to a magnet are most of the ferrous metal, nickel and cobalt.
9.  Ductile
Metals have the ability to become permanently deformed without cracking or failing.
Many metals have this property such as aluminum and copper.
10. Malleable
The metal have the ability to be hammered or rolled into various shapes.
11.High specific gravity—
Specific gravity is the ratio of the mass of a certain substance to that of an equal volume of water. In most cases metals have a higher specific gravity than water.
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6. CHEMICAL PROPERTIES
Metal will combine with other elements such as oxygen, sulfur and the halogens. Iron has a special affinity for carbon.
They are electropositive in character (due to the tendency to lose electrons)
They are present as cations (positively charge, taken in) when their salts are dissolved in water.
Whenever metals are fused together or by some means chemically combine at their point of contact by a process like welding, a sharing of electrons take place.
The outer ring is not full in the electron, then atoms of two different elements, or two of the same come together to fill the outer ring.
If the outer ring is fill, than there is no sharing of electrons like inert gases like argon
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7. TERMINOLOGY OF METALS 1. Adhesion
The sticking together of two unlike metals involving a
mechanical bond.
The mechanical bond involves the flowing of a metal in a
liquid form into the pores of a metal in a solid form. Brazing
and soldering are examples of adhesion.
2. Alloy
A mixture of two or more metals or metals and one or more non- metals.
3. Annealing
Softening metal and removing the brittleness. This is done by heating the metal to a cherry-red color and allowing it to cool slowly in vermiculite or dry hot sand.
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8. TERMINOLOGY OF METALS 4. Carbon
An element (symbol C), nonmetal often mixed with iron.
5.   Casting
In metalwork, pouring metal into a mold, so that after cooling it will be certain shape or form.
6.   Cementite
The compound iron carbide (Fe3C) which is quite hard and brittle.
It is iron with carbon dissolved in it.
7.    Ferrite
Elemental iron which is usually very soft.
It is only slightly harder that copper in a body centered cubic lattice composed of nine atoms. Examples are auto fenders and parts of soft drink cans.
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9. TERMINOLOGY OF METALS 8. Fusion The mixing of molten metals. 9. Grains
Most similar crystals closely packed together in standard symmetric pattern.
10.  Hardening
Making steel harder.
This is done by heating the medium or high carbon steel to a cheery red color and cooling it quickly in water. Hardened steel is not only extremely hard but also brittle. Hardening is the first step in tempering.
11.  Hardness
The ability of a metal to resist denting.
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10. TERMINOLOGY OF METALS 12. Heat A type of energy.
It is stored as molecular motion within a substance.
Heat always mover from a substance of high heat content towards a substance of low heat content.
13.  Iron
A crystalline metallic element. Symbol Fe.
14.  Lattice
The fundamental geometric structure of the crystals. The three types of lattices found in iron are body-centered- cubic, face- centered-cubic and hexagonal. The body- centered-cubic is composed of 9 atoms. The face- centered-cubic is composed of 14 atoms. The hexagonal lattice is composed of 17 atoms.
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11. TERMINOLOGY OF METALS 15. Melting point
The point at which a metal starts to change from solid to liquid.
16.  Tempering
Obtaining the desired hardness and toughness in metal. The degree of hardness, brittleness or toughness is determine by the job expected of the steel.
 17. Toughness
The resistance to fracture after permanent deformation.
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12. CLASSIFICATION OF METALS
Ferrous Metal : Metals whose chief ingredient is iron.
Non-Ferrous Metal : Metals which have no iron and made up of single elements
Ferrous Alloys : Metal made up largely of ferrous materials but have other elements in sufficient quantities to change the ferrous characteristics.
Non-Ferrous Alloys : Metals that are made up of two or more non-ferrous elements.
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13. Ferrous Metal Pig iron (Mine from soil) Cast iron Wrought Iron Steel
low carbon steel
medium carbon steel
high carbon steel (Drill bits)
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14. NON-FERROUS METALS Aluminum Copper Lead Magnesium Nickel Tin Tungsten
Zinc
Silver
Gold
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15. FERROUS ALLOY METAL Manganese steel Chrome steel Nickel steel
Stainless steel
Tungsten steel
Molybdenum steel
Vanadium steel
Silicon steel
Aluminum steel
Phosphorus steel
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16. Non-Ferrous Alloy Metals
Brass
Bronze
Solder
Mixing of tin & lead
Melting point is lower.
Pewter
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17. SEE YOU LATER THANKS FOR ATTENTION
Teknologi dan Rekayasa