1. Metallurgy and Metal’s Physical Properties

2. Objectives Identify and explain the terms associated with metals.
Describe the properties and structures of metals.

3. Metal 75% of all elements are classified as metals Alloy
Mixture of two or more metals, and metals and nonmetals
more desirable properties and are less expensive than pure metals.

4. Adhesion High temperature creep
The slow stretching of steel under stress at high temperatures.
Adhesion
The sticking together of two unlike metals involving a mechanical bond.
Bond is caused by liquid metal going into the metal’s pores

5. Annealing Annealing Tempering Establishing the desired hardness
the softening of metal and removing of the brittleness.
done by heating metal to cherry red and then allowing it to cool slowly in vermiculite, hot sand, or a furnace.
Tempering
Establishing the desired hardness

6. Hardening The process of making steel harder
Done by heating the steel to cherry red color, then cooling it in water.
Hardened steel is not only extremely hard but also brittle.
The first step in tempering.
Hardness
The ability of a material to resist being indented.

7. Casting Pouring melted metal into a mold Malleable
The ability to be shaped by beating or rolling

8. Properties and structures of Metals

9. Properties
The distinct characteristics used to help identify a given metal
Includes:
brittleness
color
corrosion resistance
ductility
malleability
strength.

10. There on 6 different Ways to classify metal

11. 1. Mechanical hardness brittleness ductility percent elongation
toughness
wear
strength

12. . Tensile strength Compressive strength
ability of a metal to resist being pulled apart
Compressive strength
ability of a metal to resist deformation by forces pushing it together.

13. . Shear strength Fatigue strength
metal resisting forces in opposite directions
Fatigue strength
Metal taking repeated loads without deforming.

14. Impact strength Flexure strength
the ability of a metal to resist shock.
Flexure strength
Ability of a metal to bend without deforming or breaking.

15. 2. Chemical properties
The chemical make-up of the metal and its ability to resist reaction with the environment.
Chemical properties are:
Acidity or alkalinity of the metal
Corrosion resistance
Resistance to acids and salts
Resistance to other chemicals

16. 3. Physical properties
Shape,
Specific gravity
Weight

17. 4. Thermal properties Characteristics such as: expansion contraction
thermal conductivity
specific heat

18. 5. Optical properties
luster
color
light transmission
light reflection

19. 6. Electromagnetic properties
electrical conductivity
magnetic permeability
galvanic action

20. 7. Acoustical properties
relate to the ability of a metal to transmit and reflect sound

21. Crystal Structure
The way molecules of a substance are arranged or how they are packed or fitted together.
The pattern these atoms make is called a space lattice.
14 lattices involved in the study of metals
Only three common structures are of real importance.

22. The body-centered cubic
Has nine atoms.
Strength and the difficulty with which they are worked when cold.
Ex: iron, molybdenum, chromium, tungsten, and vanadium at room temperature.

23. The face-centered cube
Has fourteen atoms.
they are plastic and malleable.
Ex: iron, aluminum, nickel, copper, lead, platinum, and silver.

24. The close-packed hexagon
Has seventeen atoms.
non-plastic and must be heated before they can be worked.
Ex: cadmium, cobalt, bismuth, magnesium, titanium, and zinc.