Papers by Keyword: Refining

Abstract: In order to bring on the producing of low & ultra-low sulfur steel and optimal control of refining slag composition and property converter tapping, slag oxidability and oxygen activity have been analyzed. In addition, optimal refining slag composition and adding process, adding system of modifying agent and bottom argon-blowing in ladle were researched as well. On this basis, refining process of low-sulfur steel has been optimized. The results show that sulfur content in steel is as low as 6.6×10^-6~40×10^-6，which achieved the production of low sulfur steel.

Abstract: In order to produce low oxygen steel with high quality, converter slag-tapping, slag oxidability and oxygen activity have been analyzed. In addition, modifying and adding process of slag, control of slag oxidability and bottom argon-blowing in ladle were studied as well. On this basis, refining process which is beneficial to low oxygen steel producing with converter-continuous casting process has been developed. The results show that content of T[O] in steel is not more than 15×10^-6.

Abstract: RH vacuum refining is a complex metallurgical process, which includes multiphase flow, heat transfer and different chemical reactions. It plays an important role in the iron and steel making. The fluctuation of free surface in the vacuum vessel has a very significant effect on the quality of the molten steel. In the present study, a 3D mathematical model of the gas-liquid-slag three-phase flow was established in the vacuum vessel of RH-TB. The results show that the fluctuation of free surface in the vacuum vessel and the diameter of slag-hole are both influenced by the injection rate of oxygen and the circulation rate of molten steel. When the injection rate of oxygen is changing from 2.355m3/s to 3.925m3/s, the fluctuation of free surface is changing from 0.175m to 0.28m and the diameter of slag-hole is changing from 0.746m to 0.852m. The present study could be helpful to optimization and refining effect improvement of RH vacuum circulation refining furnace.

Abstract: Xylanse named as Pulpzyme HC was used to modify bleached softwood pulp before refining. The efficiency of modification by different enzyme dosage was invested in this paper. The result showed that enzymatic treatment decreased the dissolved charge and absolute Zeta potential of the slurry and increased the fiber surface wettability. Appropriate Pulpzyme HC (0.4u/g) could improve the refining efficiency by 9.5°SR. The brightness and bulk of hand sheets increased with the increasing of the enzyme. Tensile index and tear index of hand sheets reached the maximum at the enzyme dosage of 0.2u/g. In this dosage, fiber length, knot index and curl index of fiber increased. But excessive enzyme decreased the tear index and had no effect on the tensile index.

Abstract: A new porous nozzles for refining molten aluminum were made from mullite，graphite powder, red mud and sodium silicate. The relationships between graphite content and permeability, sintering parameters and permeability, graphite content and compressive strength were investigated, respectively. The internal structures of the nozzle before and after sintering were observed by SEM. The experimental results show that the permeability of sample can be improved by sintering at temperature of 1000°C for 2 hours. As graphite content increases, the permeability of sample increases, yet the ultimate compressive strength decreases. The compressive strength can be enhanced by using combination of different sizes of mullite particles.

Abstract: The costs of salt flux treatment have received a strong industry focus as solid flux addition has replaced the usage of Chlorine for alkali and inclusion reduction. The magnesium chloride component has historically had the higher cost incidence but since 2008 the potassium chloride component because of its role as feedstock of fertilizer production has been subject to large commodity price driven fluctuations and rose 350% in 200 – 2009. As demand for world food production and bio fuels increases as the global economy recovers further price rises can be anticipated. A programme of work and field results are presented on the development of an alternative flux system based on a ternary composition.

Abstract: It was investigated that the effect of electric pulse modification (EPM) on the hot tearing of Al-5%Cu-0.8%Mn alloy. The results indicate that hot tearing tendency of all samples can be reduced treated by electric pulse with different parameters, moreover, hot tearing stress of alloy with EPM was enhanced 3 times or so than that of samples without treatment. Decreasing the quantity of eutectic in grain boundaries, decreasing the end-solidifying temperature of the alloys, and refining the grains are main causations for increasing hot tearing resistance of Al-5%Cu-0.8%Mn alloy by electric pulse modification.

Abstract: It was investigated that the effect of electric pulse modification (EPM) on the hot tearing of Al-5%Cu-0.8%Mn alloy. The results indicate that hot tearing tendency of all samples can be reduced treated by electric pulse with different parameters, moreover, hot tearing stress of alloy with EPM was enhanced 3 times or so than that of samples without treatment. Decreasing the quantity of eutectic in grain boundaries, decreasing the end-solidifying temperature of the alloys, and refining the grains are main causations for increasing hot tearing resistance of Al-5%Cu-0.8%Mn alloy by electric pulse modification.

Abstract: With China cast CAE / InteCAST, we analyzed the ordinary valve casting parameters of solidification process, flow and heat transfer, and frequency smelting refining furnace used in the process of feeding wire, argon technology in the intermediate. Comparison-ray testing and physical anatomy of the results, we developed nuclear power valve steel casting process parameters. The results showed that the software forecast casting the shrinkage tendency of value; frequency smelting refining controlled sulfur, phosphorus and aluminum content; products fully comply with the ASTM A216/A216M overcome hot cracking defects, improving the casting ability of anti-fatigue.

Abstract: The aim of this work is to study the influence of beating and refining as well as the fibre furnish on the properties of silk paper, such as air permeance, softness, pore size, tensile index and burst index. The results showed that the beating characteristic of silk fibre was similar to that of plant fibre, they all had the characteristic of fibrillation. Silk paper had excellent softness and air permeance when the beating degree of silk pulp was 20 °SR, 181.3 μm/Pa·s and 2.5 mN·m²/g respectively, which was superior to paper made from plant fibres of the same beating degree. The minimum average pore size of silk paper was 5.11 μm at the beating degree of 20 °SR, and it decreased with the increase of beating degree, reached 0.79 μm at the beating degree of 67 °SR. With the increase of beating degree, the tensile index of silk paper increased at first, and then decreased. The burst index of silk paper showed a upward trend, but the softness and air permeance of it constantly decreased. The tensile strength of paper made from mixed-furnish pulp consisting of silk and softwood reached the maximum when the amount of silk fibre was 4%, and its air permeance increased with the increase of silk fibre.