Strong decarburization at a billet corner - 1.2516
Surface decarburization is a loss of carbon in the skin of the material. Favoring factors are high temperatures and larger quantities of oxygen in the atmosphere. Characteristics for a Surface decarburization are increased amounts of ferrite, reduction of the amount of carbides or also lamellar pearlite at spheroidised hypereutectoid steels. In the following example a billet corner of the pre-material was strongly decarburised and this is the reason for the defect at the wire rod.
Rod wire 12,00 mm round - spheroidised