This square profile has been cold drawn by a round pre-material.
During the production problems appeared in the form of corner cracks. The material
showed a well spheroidised annealing structure, with strong carbide precipitate
on the grain boundaries. A structure with strong grain boundary precipitations
in the area of the broken corner also became stated. The structure at the three
corners without breaks had, however, only low grain boundary precipitations. The
flanks of the defects didn't show any decarburization, so they had arisen after
the last heat treatment. The different corner form can be seen in the dissimilar
forms of the microstructur. Bad flow behavior at the drawing.
6,00 mm round - pickled , annealed , drawn at square profile