Lines with strong pickling attack - 1.4401
After pickling the wire material line-type cavities have been observed with an amplified pickling attack on the surface. A metallographic examination showed a strong grain boundary attack in these areas because of carbide precipitates amplified on the grain boundaries . By the carbide precipitates the resistance against corrosion has been reduced drastically because of the chromium loss in the environment of the carbides. Since the rod wire was not subjected to any heat treatment, the cause of this defect must be looked at the pre-material (billet).
Rod wire 13,50 mm round - untreated , pickled