Papers by Author: Ding Guo Zhao

Abstract: According to the actual situation of refining high nitrogen steel with the laboratory high pressure reaction axe, the molten steel flow field in the high-pressure and bottom-blowing nitrogen reactor was simulated by using the software Fluent. The rules of the influence of pressure factor on the molten steel flow field characteristics, turbulent kinetic energy and gas content were explored. According to the characteristics of the flow field and gas-liquid two phase structure, the rules of the influence of pressure factor on nitrogen concentration distribution were analyzed. So some useful theoretical basis and guidance were provided for laboratory refining high nitrogen steel and industrial production in the future.

Abstract: The experiments of smelting high nitrogen nickel-free stainless steel were carried out in the high temperature and high pressure reaction kettle. The nitrogen content was more than 1.36% by using the method of high pressure and bottom blowing nitrogen. With controlling high pressure nitrogen atmosphere and bottom blowing nitrogen, internal react were investigated by single factor experiment. Experimental results shown that there is saturated solubility, while smelting 18Mn18CrN steel with high pressure and bottom blowing nitrogen. Thermodynamic calculation model nitrogen solubility under the condition of high pressure was established, and the influence of nitrogen partial pressure on saturated solubility was researched.

Abstract: We studied the nitrogen macrosegregation of the HNS, and found that there were severe vertical segregation and horizontal segregation. Both of them are normal segregation. The study shown that the overflow area of nitrogen bubbles in the process of solidification is due to the nitrogen macrosegregation.

Abstract: The environment is a human living space. The harmonious development of the human with the natural environment is the basis for sustainable development. With the improvement of society development and human creativity, environmental pollution and ecological destruction has exacerbated the environmental carrying capacity continued to decline. Accompanied to industrialization and urbanization and society growth, ecological environment continues to worsen. Human existence was under the challenge from the natural world. The obvious contradiction was between society development and environmental protection. Environmental issues were restraining the further development of the global economy.

Abstract: The method of smelting High nitrogen steels by blowing nitrogen from the device bottom is a promising way of increasing nitrogen with gas. Introduced the device and technical development of smelting High nitrogen steels in domestic and foreign countries, expounded the method and character of dissolving nitrogen into liquid steel at high temperature and high pressure, and analyzed the advantage of increasing nitrogen by bottom-blowing nitrogen. The domestic research is at the developing period of experimental research. The High nitrogen steels which content is more than 1.0% was produced with bottom-blowing nitrogen method at high pressure. The velocity of dissolving nitrogen with bottom-blowing was increased and the smelting time was shortened. The technical effect was very good.

Abstract: Based on the phase diagrams analysis, the activity model of Fe-C-B ternary system was established with the ion and molecule coexistence theory. The activities of Fe, C, B, Fe3C, FeB, FeB2 and B4C in melt were calculated by analyzing the model. We have researched the thermodynamic condition of boron oxide reducing with carbothermic method and analyzed the effects of CO partial pressure, B2O3 content and slag type for the lowest smelting temperature. In normal pressure, the carbon content is high in melt, so it needs 2000°C for decarbonizing and chrome remaining. When CO partial pressure is 0.1 kPa and CaO content is less 60%, the lowest temperature of smelting ferro boron could be below 1600°C.

Abstract: In the paper, the reaction of solid-solid model was researched and we confirmed the reaction equation. The experiments in the lab shown that the t1/2 is 11.8min in the ferrosilicon reduction boron anhydride reaction at low temperature. The yield of boron is higher by direct reduction method smelting. In the boron oxide reducing experiment, the yield minimum is 76%, the maximum is 82%, and the average value is about 79%, which provides favorable foundation conditions for smelting amorphous mother alloy.

Abstract: Analyzed the reaction between slag and liquid iron and done a lot of experiments in the Lab to find the effect of many factors. It shown that putting into CaO to low the reaction activity with small amount of calcium oxide added, it can make the expansion in reaction to be inhibited, and improve the content of CaO in further. Silicate is high melting point material in the reaction product. After the reaction it reduce the slag fluidity to the slag with addition of CaF2, which can further improve the effect of reduction reaction.

Abstract: Researched on the refractory material corrosion by experiments. Each refractory was measured to take four different parts, and the average corrosion thicknesses of silicon carbide, quartz and corundum were 0.52mm, 1.03mm and 1.40mm. The corrosion of corundum refractory was most serious, and quartz refractory had a certain degree of corrosion, but it was not very serious. The corrosion of silicon carbide refractory was the least. In the experiment in intermediate frequency furnace, only upper and lower parts of slag line were connected to the refractory and the degree of corrosion was little for silicon carbide crucible. Slag part of the wall thickness was about 16.6mm after the reaction. Amorphous master alloy parts of the wall thicknessis about 16.9mm. For quartz crucible, refractory corrosion was much bigger, which was 10 mm thick before reaction. The erosion thick was about 2~3mm. It was a little thicker than corrosion experiment in static crucible.

Abstract: The mechanism of refractory material corrosion was analyzed. The laboratory amorphous alloy smelting of the mother prefabricated crucible, reaction process is basically to crucible refractory material of blast furnace slag corrosion, melt corrosion is small. Generally smelting amorphous mother alloy was a difficult thing, and it shown that the basicity was better around 1.0. Compared with quartz refractory, it is good to choose the silicon carbide refractory materials, while smelting amorphous alloy.