Transmission Electron Microscope Observations of SUS304L Stainless Steel Heat Affected Zone

The micro-structure distribution of SUS304L stainless steel heat affected zone was investigated by transmission electron microscopy. The results are as follows: (1) Small ferrite phases were observed at sub-boundaries near the fusion boundary in the coarse grained region by transmission electron microscopy, which were not recognized by optical microscopy. (2) The degree of recovery in the dislocation structure became lower in the heat affected zone with the distance from the fusion boundary. (3) No grain boundary precipitations were observed in the grain boundary etched region by transmission electron microscopy. (4) The Vickers hardness distribution can be explained by the distribution of grain size and dislocation density.