Figure 66 is a photograph of a section through a welded joint. The surface has been polished and treated to reveal the microstructure. The workpiece has a fine, uniform grain structure that becomes slightly coarser close to the weld. The weld metal has a coarse grain structure, with the pattern of grains creating an impression of material flowing away from the workpiece into the weld metal. There is a scale bar indicating that the grains in the weld metal are a few hundred microns in size. Those in the workpiece are too small to measure at this magnification.

 4.6.2 Fusion welding