Nowadays, the concept of high entropy alloys (HEAs) has expanded the limits of metallurgy and high-quality metallurgical HEAs ingots have already been successfully obtained on an industrial scale. High Chromium Cast Irons (HCCI) and Multi-Component Cast Irons (MCCI) are known to be a useful material for applications when abrasion resistance is required. Inspired by the concepts of high-entropy alloys, a base HCCI was modified, by adding other carbide-forming elements, at concentrations higher than what is currently used, in order to develop a new class of white cast iron, High Entropy White Cast Iron (HEWCI). The characterization of carbides precipitated during the HEWCI solidification was performed by scanning electron microscopy, energy dispersive spectroscopy, electron backscattered diffraction (SEM/EDS/EBSD) and X-ray diffraction (XRD). With the characterization techniques employed, the as-cast microstructure obtained of HEWCI is composed of approximately 50% of austenite matrix and 50% of different types of carbides, MC, M7C3 and M2C carbides.
1 January 2010 in Ironmaking & Steelmaking: Processes, Products and Applications
Heat transfer coefficients in the mould were determined by the inverse method and they are related to both process conditions and carbon equivalents of steels. Experimental data were obtained from an industrial plant by temperatures measured in moulds of the continuous casting machine by thermocouples placed in the mould wall in known positions. The temperatures are compared to profiles of simulations by the numerical model of both solidification and heat transfer processes previously examined. As a result, the numerical model calculates the heat transfer coefficients in the metal/mould interface for heats cast with different process parameters. The results make possible the determination of expressions for the calculation of the interfacial metal/mould heat transfer coefficients that include the effects of steels grades, mould faces, casting speed, mould taper, mould section and pouring temperatures for a range of process parameters.
The present work focuses on the investigation of thermal profiles in copper molds and at the strand surface during continuous casting of different steel grades in an industrial plant. Thermocouples embedded in the mold walls were used to measure temperatures along the mold length. Noncontact pyrometers positioned at different locations along the machine monitored the strand surface temperatures. The experimental results permitted an interrelation between steel grade, mold section (240 × 240 mm, 180 × 180 mm, and 150 × 150 mm), and mold wall, and strand surface temperatures to be established as a function of casting operating conditions. It is shown that the mold outer face (external curved wall) has the highest temperature distribution from the meniscus to the bottom of the mold followed by the inner and side faces, respectively. The deepest meniscus is shown to occur for the 150-mold, and the 180-mold is shown to have the highest temperature profiles along the mold length in all faces examined. Low carbon steels present the highest strand surface temperatures along the machine when compared with those of medium and high carbon steels. When the steel composition is parameterized, it is shown that the 150-mold has the smaller strand surface temperature close to the mold exit when compared with the 180 and 240 molds, and it is shown that this behavior changes after the unbending point.