SOAKING ANNEALING TREATMENT METHOD FOR HIGH CARBON STEEL

摘要

PROBLEM TO BE SOLVED: To provide a soaking annealing treatment method for high carbon steel by which huge carbide such as eutectic carbide is rendered harmless substantially, occurrence of flaws such as the surface crack can be prevented or reduced, and the treatmentprocessing time can be shortened.;SOLUTION: When a cast billet of the high carbon steel is heated to a predetermined soaking temperature in a heating furnace, the cast billet is heated at heating rate of ≤50°C/h in the transforming temperature zone from the starting point of the transformation to the finishing point of the transformation, and is heated at higher heating rate than the heating rate in the transformation temperature zone in the temperature zone other than the above temperature zone, and then is held in a predetermined soaking temperature. Further, it is preferable that the heating rate in the temperature zone of lower than the starting point and/or the temperature zone exceeding the finishing point is ≤100°C/h. Furthermore, an isothermal conservation may be performed at just below the starting point of the transformation and/or just above the finishing point of transformation.;COPYRIGHT: (C)2010,JPO&INPIT