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Name: David
Status: Student
Age: 40s
Location: N/A
Country: N/A
Date: N/A


Question:
What is the difference between physical properties and mechnical properties of steel?



Replies:
I am not sure I really follow your question, but I'll see if I can answer it. I take it you mean physical properties to be things like mass, melting point, etc., whereas mechanical properties are things like modulus of elasticity, hardness, etc. Both physical and mechanical properties are going to be dependent on chemical composition. More carbon, less carbon, more nickel, less nickel, etc. are going to influence what kind of steel you have. That is why you see numbered steels because they represent a certain composition.

However, mechanical properties can be greatly influenced by how they are treated during manufacturing. Steels can be quenched in water to give one value of hardness, whereas they can be quenched in oil to give a different value for hardness. Most of the mechanical properties are influence on what phase of material is allowed to develop as the steel is made. Quenching is just one way to influence phases and grains of a piece of material. Heat treating and annealing are just a couple of other ways to work a metal.

In short, physical properties such as mass and melting point are "kind of" locked in by the composition of the elements that make up steel, but mechanical properties can be greatly influenced by how the metal is treated during its creation. Hope this helped.

Dr. C. Murphy



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