(Light-)Microscopic And Electron-Microscopic
Metallography uses microscopy (max. magnification of 1:1000) to obtain information about the material’s crystallographic structure (crystal/grain organization), the material’s elongation and crystal distribution, and its orientation and overall structure. At Brechmann-Guss, in addition to general comparison of materials, we pay particular attention to the type of graphite which forms (lamellar/flake or spheroidal), as this is the defining feature of either cast iron with flake graphite (grey cast iron) or with nodular graphite (SG cast iron). For SG cast iron, information about the size and even distribution of the graphite nodules is also important; the type and shape of certain precipitates may be critical as well. These nature of these factors can be determined and evaluated based on prepared micrographs, in order to decide whether the given production lot can be released for the customer or whether the batch should be blocked until each part can be tested individually (a result which, of course, we are less happy about).