Because of unfavorable parameter during the solution annealing,
too high temperature or too long holding time, strong scale layers can be formed.
This scale layer is partly accompanied by stronger formation of scars. Unless by
wrongly selected annealing parameters, a furnace disturbance yields the same defect
picture. By influence of oxygen at increased temperatures metals (steel in this
case) can form oxidic layers on the surface. These are described as a scale. Grain
boundary oxidation is a type of the scaling hurrying on ahead at the grain boundaries.
10,00 mm round - solution annealed