Thursday, October 22, 2009

Physical of Working Material

Physical Properties of Working Materials


Classification of Materials:


1. Metals
  • Ferrous Metals: Steel, Cast Iron
  • Non Ferrous Metal: light metals, heavy metals, unalloyed steel, alloy
2. Joining Materials:
  • Joining different substances: sintering, adhesion, injection, vapor deposition, soldering
3. Non Metals:
  • Natural substances: wood leather, asbestos
  • Artificial substances: plastic, glass, ceramic, concrete
  • Auxiliary materials: lubricant and coolants, grinding and polishing materials, adhesives, cleaning agents. 
 

Classification of material according to technical criteria:

  1. Light metal and heavy metals (limit = 4.5 g/cm3)
  2. Melting point: low melting point metals (below 1000oC), medium melting point metals (between 1000 – 2000oC), high melting point metals (above 2000oC)
  3. Chemical resistivity: Noble metals, e.g. gold, silver, platinum, and base metals, e.g. iron, zinc, aluminum.
  4. Significance for industry: Ferrous metals, non-ferrous metals.
  5. Processing (primary forming, re-forming, cutting and joining); casting materials, forging materials.

Bodies and their state of aggregation:


Any limited quantity of a substance is known as a body in physics, e.g. a plate of plastic, a piece of round steel, a quantity of water or acid in a beaker, a quantity of hydrogen or acetylene in a glass flask. The three major classes here are solids (plastic, steel); liquid (water, acid) and gases (hydrogen, acetylene).

Solids have fixed shape and volume. The shape of the body can be change by applying force, e.g., by bending or compressing, in the course of which, however, the volume remain practically unchanged.

Liquids have no definite shape; they rather assume the form of the vessel in which they are contained and form a nearly horizontal surface. The volume of a liquid, too, cannot be changed even under great pressure.

Gases have no definite shape and distribute themselves uniformly over the available volume of expansion. The smallest particle are completely free, move randomly and are at relatively large distance from each other.

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