Engineering Materials, Manufacturing and Electrical Machines Essay

Engineering Materials, Manufacturing and Electrical Machines - Essay ExampleThis conversion is carried out by de causeing the metal permanently by the application of forces on it. The desired work or final shape of the metal defines which type of de prepareation process has to be applied. Physical and mechanical properties of metal such as strength, hardness, brittleness, elasticity, plasticity, malleability, toughness, grain structure, isotropic behavior etc. also play an important role in deciding which kind of manufacturing process is to be used.Metals are generally ductile materials with a large plastic range on stress strain curve. This is due to the metallic bond present in them (Askeland, 2009 33). The stress strain curve of crackers steel is shown here, (although it will be different for each metal, it will follow more or less the same pattern) The area after the yield take down is the plastic range of mild steel. Clearly, it can undergo significant amount of plastic defor mation before it finally fractures. Same is true for other materials. Hence, to form a material in to desired shapes, plastic deformation is a desirable process.There are many different yield criteria which tell us the stress required to cause permanent yielding in a material. Out of these Tresca criterion is considered suitable for ductile materials (Marciniak et al., 2002 20). It suggests that yielding occurs (or plastic deformation starts) at a point when shear stress crosses a certain limit.Formability of a metal is its ability to deform in to desired shape or form without failure. Failure can be due to different physical phenomenon like shearing or necking etc. (Kalpakjian and Schmid, 2001 424).One of the earlier developed tests is form Test. In this test, a steel ball or any circular profile made of steel is pressed against the sheet with uniform increment of stress. The profundity to which the sheet can be deformed is a measure of its formability. This method however has it s own limitations as the results obtained are specific to the test conditions. The