Causes of the hot ductility drops of steels

• DOI: 10.1134/s0036029514090092
• Publication Date: 2015-01-07T00:23:11Z
• Authors: N. G. Kolbasnikov; M. A. Matveev; V. V. Mishin; P. A. Mishnev; S. V. Nikonov
• Keywords: Ductility (Earth science); Slab; Microalloyed steel

The effect of conditions of continuous casting and hot rolling of steel on the high-temperature ductility of a microalloyed pipe steel of strength class Kh42 and 17G1S-U steel is studied. A Gleeble-3800 thermomechanical facility is used to perform physical modeling of the hot ductility of steel. The temperature dependence of the hot ductility of steel is determined under various slab cooling conditions in a continuous caster and during hot rolling. The ductility drops of iron and steels is found to be mainly caused by an increase in the elastic modulus near the temperatures of the polymorphic transformation caused by first- and secondorder phase transformations (polymorphic and magnetic transformations, respectively). Structural factors, such as the grain size, excess-phase inclusions located along initial grain boundaries, and interstitial impurities, lead to an additional decrease in the ductility.