The hardness of materials and life applications on it
Hardness of materials
Some solid substances are soft at room temperature such as the rubber , and some solid substances need heat to become soft and easy to be shaped such as the metals , and some solid substances can not be soften by heating such as coal and sulphur .
Hardness of materials has been assessed by the materials resistance of cutting , scratching or bending , and it is measured by the resistance which a smooth surface offers to abrasion .
The degree of hardness is determined by observing the comparative ease or difficulty which one mineral is scratched by another , Hardness is the property of a material that enables it to resist the plastic deformation by penetration .
Hardness is the resistance of a material to deformation , indentation or penetration by drilling , abrasion , impact or scratching , Hardness is measured by hardness tests such as Brinell , Rockwell , Knoop or Vickers tests , and there is no standard hardness scale .
The hardness of alloy is the diameter of the dent an alloy measured when 1 kg of weight is dropped onto it , The smaller the diameter of the dent formed on the alloy , the harder the alloy .
The hardness tests serve an important need in industry , these tests are based on experiments and observation ,They are able to detect certain differences between the materials .
The importance of hardness testing has to do with the relationship between the hardness and other properties of the material , and the hardness test is preferred because it is simple , easy and relatively nondestructive .
Life application of hardness
The screwdrivers are made of steel iron because it is very hard , and the rods used in building houses concrete are made of iron not copper because the hardness of iron is more than that of copper .