Advanced Materials Research Vols. 476-478

Abstract: Metallic materials are corraded unavoidably with deterioration of eviroment in heavy industry cities. Transformation of rust layer structure of Q235 atmospheric corraded in Tangshan industrial estate was analyzed with instrumentalities of X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) , EDS and so on. The results showed that corrosion outcomes of Q235 transformed from FeOOH and Fe3O4 to FeOOH, Fe3O4 and FeSO4 through insolation in one year.

Abstract: The influence of different dearsenization agents on the arsenic removal in molten iron (steel) was studied. The result indicates that low temperature is beneficial to the process of arsenic removal reaction and the different dearsenication agents have different arsenic removal effects on arsenic containing molten iron . However, The dearsenication additive selected has a merely maximum arsenic removal rate of 58.6% while other dearsenic agents have the arsenic removal rate no higher than 25%. Relevant researches also indicate the phosphorus contained in the molten iron has a relatively significant influence on the arsenic removal rate. With the reduction of the content of phosphorus in the molten iron, the arsenic removal rate is improved significantly.

Abstract: In this paper, firstly, the equilibrium solubility product formula of MoC with NaCl type cubic crystal structure in ferrite has been deduced by thermodynamic method, according to the free energy change of molybdenum and carbon dissolved in ferrite and the formation energy of MoC. On the basis of deducing activity coefficients of Mo in iron, the solubility product formula of MoC in austenite has been obtained according to the relationship of solubility product of MoC in austenite and ferrite. Finally, the solubility products for MoC and NbC in iron are compared. The solubility product formulae of MoC deduced would play an important role in related theoretical research and practical production.

Abstract: A circuit using the singlechip as key component for temperature control for DFB laser diode is designed in this article. An imbalance electrical bridge for measuring the temperature of laser diode is used in this circuit, and the result of measurement is converted to digital quantity by ADC. After that, the error signal is gotten through the digital PID calculation. At last, the DAC chip make error signal be voltage to drive power amplifier for TEC. The function of set point and display of real time temperature is also added. After the test for a long time, we confirm the precision of temperature is better than ±0.001°C.

Abstract: The optimization of the location and height of weir & dam with drain holes in a single-strand continuous casting tundish was carried out from the view of fluid flow characteristics by physical modeling using a 0.4 scaled water model and mathematical modeling study. Considering simultaneously reducing the remaining melt, maximizing the plug flow and avoiding the short circuited flow, the dam with two upwardly inclined drain holes was optimized. The parameters such as location and height of weir & dam Lw/L, Ld/L, Hw/H and Hd/H are important to fluid flow in tundish. Among them, the location and height of dam were more critical to the overall fluid flow in tundish. The gap between weir and dam was also very important, the gap length that smaller than 0.266 will be preferred. The dead region behind the weir was enlarged and the tracer flow through the drain holes of dam was weakened as increasing the gap of weir and dam. In present study, the parameters of the optimized Case7 are Hw/H 0.448 (162/362), Hd/H 0.718 (260/362), Lw/L 0.4 (480/1200) and Ld/L 0.667 (800/1200). For the fluid flow field, the near surface flow which beneficial to inclusions removal existed both above the dam and through the upwardly inclined drain holes. While the case of bottom grooved dam used may lead to short circuited flow through the grooves.

Abstract: Reduction experiments between slag-metal at 1600°C were carried out by using equilibrium method, in which the slag phase was CaO-SiO2-Al2O3 containing Nb2O5 or Fe(NbO3), while the metal phase was Fe-C or Fe-Si. Reduction ability of carbon and silicon as well as reduction characteristics of Nb2O5 and Fe(NbO3) were compared.

Abstract: Coking is the process of coal pyrolysis. It can produce a large number of PAHs which are the typical persistent organic pollutants with their teratogenic, carcinogenetic, and mutagenic. The writer studied the PAHs in single coal coking process through laboratory sampling and high-performance liquid chromatography analysis, observed and summarized the structure distribution of 16 kinds of priority recommended PAHs in three single coal coking process, and provided the foundation data for the control of PAHs.

Abstract: In this paper, the tensile properties of dual phase (DP) steels with different martensite contents have been studied. Two steels with 0.09 and 0.15% carbon were used for the production of DP steel samples via intercritical annealing treatment, and the deformation behaviour of DP steel samples were examined during tensile loading. Although DP steels usually show two-stage work hardening behaviour, DP steels in this study with relatively high martensite content and coarse islands size exhibit a three-stage work hardening behaviour. This unusual behaviour was attributed, with the help of SEM micrographs, to decohesion of martensite-ferrite interface and martensite cracking.

Abstract: The effects of boron on the undercooled austenite transformation of low carbon Mn-Nb steels during continuous cooling were investigated in this study. Five kinds of steel specimens were fabricated by varying boron contents. Continuous cooling transformation (CCT) curves of the investigated steels under deformed conditions were constructed by a combination of deformation dilatometry and metallographic methods. The results indicated that a small amount of boron efficiently increased the hardenability of steels and lowered transformation temperature, which leading to a finer bainite microstructure and an increase in hardness.

Abstract: The influence of microstructures with different heat treatments to stimulate the weld fusion zone and HAZ on corrosion properties of X80 pipeline steel was investigated in alkaline sand soil using electrochemical measurement and surface analysis(SEM, EDS and XRD). The results showed that the microstructure of X80 steel affected the properties of corrosion product layers. Generally, X80 steels with heat treatments had a higher corrosion rate than the as-received steel. The increase of pearlite content enhanced the corrosion of ferrite through a galvanic effect. The appearance of upper bainite and martenite increased further the activity of the steel. The corrosion product layer formed on as-received X80 steel was compact and complete, provided an effective protection to the underneath steel. However, the corrosion product layers on the heat-treated X80 steels were generally inhomogeneous, loose, porous and defective, and provided minor protectiveness. The cathodic/ anodic reactions of X80 steel are dominated by the oxygen reduction and formation of iron oxides that deposit on the steel surface which was through a physical block effect to afford the protection. We shall be able to publish your paper in electronic form on our web page http://www.scientific.net, if the paper format and the margins are correct. Your manuscript will be reduced by approximately 20% by the publisher. Please keep this in mind when designing your figures and tables etc.