Metallography is a science of revealing, interpreting and documenting the microstructure of metals, alloys, and other engineering materials. Some scientists believe that this definition should be extended to include any form of testing and analysis which is in any way related to microstructure.

The importance of microstructure analysis to the modern foundry metallurgy is its capability of providing consistently accurate metallurgical data. This is only possible when sample preparation is performed according to certain acceptable standards. A successful metallographic polish is one that produces a sample surface which reveals the true microstructure.

 Three requisites for an acceptable metallographically polished surface are:

 1)      Freedom from disturbed or flowed material.

2)      Flatness – edges are not rounded , surface is not wavy

3)      Freedom from scratches which can confuse the visual analysis.

To achieve these requisites, all steps from the initial cutting to final polishing must be performed so that the main obstacles to good preparation, overheating, and mechanical deformation, are avoided. Care must be taken to remove all effects produced by the initial sample removal and to carry subsequent steps to completion, thereby removing all deformation from previous steps.