Macroscopic metallography

Macro metallography: inspect the sample with naked eye or low magnification (magnification is generally less than 50), and the sample surface can be treated or not.            Microscopic inspection: inspect the sample with a microscope, with a magnification of 50-500 generally. The surface of the sample can be treated or not.            The purpose of macroscopic and microscopic examination is to evaluate the microstructure (including grain structure, morphology and orientation, precipitation and slag inclusion) and its relationship with various cracks and cavities.