Irvin De La Paz – Mechanical Engineering Academic Projects

Metallurgy Simple Assignment

by Irvin De La Paz on 14/11/09 at 2:48 am

Summary:

For engineers  the most important thing is that  designs do not kill people. On the roots of all designs there is material selection. How do we engineers determine what materials to use?

There is a bunch of topics from engineering of materials to metallurgy that cover to some degree material selection. The project here is part of metallurgy class (the study of physical properties  of metals).

Theory

Sufficient stress (force/area) applied to a material may caused deformation.  In mechanics there are 2 types of deformations: elastic (deformation not permanent, material return to original size after force dissipate) and plastic (permanent  deformation, scary depending on the application). The deformation is measured as strain. Strain is defined as the percent of  change in lenght over original lenght.

The relationship of stress and strain is often visualizes in the graphic (as shown below).

To make such a graphic, there is an organization called American Standards of Testing Materials (ASTM) which sets the rules of how the testing should be performed.  A task was given to to test a steel after doing a hardness test (hardness is the measure of how easy or hard a material can scratch).  ASTM E8 was used to test and design the specimen.

The document  is a simple calculation about such test.  The objective of my test  was to identify what metal I was assigned.

Document available Tension_Testing_for_Steel