High Temperature Solidification Phase Transformation Rule Of Low-carbon Steel

The rule of Steel billet’s shell growth in the crystallizer is a key area in the study of thesolidification. Metallurgy scholars at home and abroad mainly analyze the influence factors ofperitectic steel slab crack formation from the macroscopic Angle such as planting, process,chemical composition, and the scholars of researching Peritectic alloy solidification mainlyfocus on theoretical research. The study of peritectic transformation phase in liquid steelshrinkage under high temperature is less, and there also is not a suitable instrument using tomeasure the rule of temperature changing, and lack of necessary scientific theoretical basis andresearching means when they analyze the phenomenon such as the shrinkage and the producingcrack of slab during the continuous casting process.This thesis mainly based on the abovesituation. It was mainly about respectively designing and manufacturing a equipment using tostudy the metal and alloy high temperature solidification phase changing. Using the software ofAnsys simulation analysis of the continuous cooling process of the steel grade in crystallizer,we can draw the law of the size choosing different slab heat transfer. Using DTA differentialthermal analyzer, we can analyze and determine Q345D high strength low alloy structural steelliquids, the temperature of peritectic reaction transition and the determination of occurringphase transition’s temperature. By comparing different cooling speed and cooling curve, itconcludes that the phase transition temperature will back during the surface with the increasingof cooling rate. With the analysis of the normal temperature the organization, it concludes thatthe micro organization is mainly ferrite and a small amount of pearlier, conforming to the Fe-C basic law of solidification phase diagram. The phase transformation pointing data plays atheoretical guiding role for subsequent non-equilibrium solidification experiments.By usingWKDHL type of consumable medium frequency electric furnace to research high temperature solidification principle, it concludes that different cooling speeds and different watertemperatures obtains different organization and hardness data.Using the experimental device from this research and development design andmanufacture to do Q345D high temperature solidification experiments, choosing the differentliquid quenching temperature,direct liquid quenching without slow cooling, quenching at thetemperature1495℃reduced by slowing cooling speed of10℃/min and quenching at thetemperature1350℃, according to the phase transformation point data from DTA equilibriumsolidification experiments, we can obtain that the different temperatures of the water quenchingresult in different microstructures. There is almost no ferrite’s formation by direct liquidquenching, a lot of blocky ferrite remained on the grain boundary at quenching temperature1495℃, and completely austenite’s formation transforming to martensite at temperature1350℃. We can get the high temperature solidification experiment device function feasibility.