Corrosion March

• types of hardness test (3)

  1. Brinell 2. Rockwell 3. Vickers
• Strength – the property that enables metals to resist deformation under load
• Compressive strength – maximum load in compression a material will withstand before a predetermined amount of deformation
• Shear Strength – the ability of a material to resist being fractured by opposing forces acting in a straight line but not in the same plane
• Tensile Strength – the maximum load in tension a material will withstand before fracturing
• Tensile Strength- ability of a material to resist being pulled apart by opposing forces. also known as ultimate strength
• Tension Test – method for determining the behavior of metal under actual stretch loading.
• Fatigue strength – maximum load a material can withstand without failure during a large number of reversal of load.
• Impact strength – the ability of a metal to resist suddenly applied loads
• Hardness – resistance of metal to plastic deformation, usually by indentation. Stiffness. ability to resist being permanently deformed when load is applied.
• Hardness - the greater the hardness of the metal, the greater the resistance to deformation.
• Rockwell Test

  • Most frequently used

  • Principle: A hard

  material can penetrate a softer one
• Toughness - property that enables a material to withstand shock and be deformed without rupturing. Combination of strength and plasticity.
• Elasticity - The ability of a material to return to its original shape after being stretched or compressed.
• Plasticity - Ability of the material to undergo irreversible deformation without fracture or damage; opposite of strength
• Brittleness - The tendency of a material to break or shatter when subjected to stress. Opposite of Plasticity.
• Ductility – property that makes it possible to withstand extensive permanent deformation from tension.
• Malleability – property that makes it possible for a material to withstand extensive permanent deformation from compression
• Phase - portion of a pure metal or an alloy that is chemically and physically homogeneous and has a distinct boundary.
• Phase Transformation

  1674°F (BCC to FCC)

  2541°F (FCC to BCC)

  2800°F (BCC-liquid)
• Ferrite – alpha iron that contains carbon atoms

  • soft, ductile material
• Austenite – gamma iron that contains carbon atoms; workable iron (forged and rolling)
• Cementite – when excess carbon atoms will combine with some of the iron atoms

  also called iron carbide (Fe3C)

  • hard, brittle
• Pearlite – specific mixture of 2 phases formed by transforming austenite of eutectoid composition into ferrite and cementite. The hard, brittle cementite reinforces the soft, ductile ferrite thus forming a natural composite