Advanced Materials Research Vols. 785-786

Abstract: Based on the characteristics of the production process and quality level of the cord steel 82A, this paper focus on the analysis of the converter terminal temperature, terminal oxidability and the converter slag on the influence of the content of titanium in steel, which combined the oxidation removing related theory of titanium element in steel, and puts forward effective measures of ultralow titanium content controlling in steel, and obvious effects have been obtained in the production: the average [Ti] content is 4.9ppm in the end products, in which the proportion of less than 5ppm is above 90%.

Abstract: The cold draw MFT8 steels with different reduction in cross sectional areas were investigated to understand the effect of aging time on the anti-stress relaxation ability of non-quenched and tempered steel. The hardness and the anti-stress relaxation ability of cold draw NQT MFT8 steel was improved after aging at 300°Csince the precipitation of submicron particles within deformed ferrite. The cold draw NQT MFT8 becomes harder and more resistant to stress relaxation with increasing aging time. The cold draw MFT8 with both 25% and 30% reduction in cross sectional areas are stress relaxation resistant after aged at 300°C for 2 hours.

Abstract: It is very important to produce 55Q steel with the exact carbon content. Low and inconsistent carbon elemental recovery problems are often encountered when adding pig iron, or carbon powder into the baths of light rail steel. This is the case because carbon presents some of the following characteristics: lower density much more than the molten steel, low solubility in the liquid steel, high affinity due to oxygen. These circumstances lead to difficulties or risks, such as: poor or erratic recovery of alloying carbon element, violent and dangerous splashing, adverse environmental impact. To counter these problems existed in conventional method, carbon cored wire was prepared and wire injection process introduced in this work, and the effects of parameters such as feeding rate, etc on carbon recovery are investigated. The results show when using the carbon wire injection method, stable carbon addition is obtained, that is, the mean recovery of the carbon absorption is 90%, and what's more, the carbon content is under control accurately and environment improved.

Abstract: The paper compares numerical simulation with experimental results of pressurized elbow piping subjected to reversed in-plane bending in elastoplastic domain. The modified AbdelKarim-Ohno model is implemented into finite element program ANSYS by writing own user subroutine in FORTRAN language. The modified AbdelKarim-Ohno model may improve the prediction accuracy of ratcheting behavior of pressurized elbow under cyclic loading.

Abstract: Inhibition of low carbon steel (LCS) corrosion in 3.5% NaCl of Pluchea indica Less. leaves extract (PILLE) has been studied using various investigation techniques such as weight loss and polarization methods. The percentage of inhibition increased as the concentration of the inhibitor increased. The results of corrosion test reveal that the extract behaves as a mixed type corrosion inhibitor. Optimum inhibition is reached from 3 mL gambir extract for immersion time of 216 hours. Fourier transform infrared (FTIR) spectroscopy result of adsorbed film on LCS surface containing PILLE shows that in changes in the functional group frequencies of the organic component of the extract.

Abstract: Electrochemical Performance of Q235 steel was measured in different temperature and different waste water. The result showed that the protection current of Q235 steel would increase with the temperature increasing.

Abstract: The difficult problems in dephosphorization pretreatment of the high phosphorous hot metal are extremely high flux consumption and very large temperature drop. Dephosphorization with multi phase flux would be helpful to solve these difficulties. In this paper, 2CaO·SiO₂ was used as the solid phase and the effect of slag composition and solid/slag mass ratio on dephosphorization efficiency of the high phosphorus hot metal was investigated in the laboratory. Dephosphorization capacity of nine multi phase fluxes was determined by means of equilibrium experiment and it is revealed that dephosphorization capacity of the multi phase fluxes is controlled by the slag composition when solid/slag mass ratio is within 0.30; as solid/slag mass ratio exceeds 0.30, dephosphorization capacity of the multi phase fluxes increases with increasing the ratio. Pretreatment experiments of Fe-0.5%P-0.15%Si-4.5%C were conducted with multi phase flux at 1400 °C (1673.15 K). The test results show that replacement of slag with 2CaO.SiO₂ particles on mass ratio of 50:50 brings about smaller finale [%P], suggesting dephosphorization of the high phosphorus hot metal with multi phase flux is beneficial to the reduction of flux consumption. Moreover, the experimentally determined equilibrium MgO concentration in the multi phase fluxes decreases with increasing solid/slag mass ratio when the ratio exceeds 0.30, implying dephosphorization with multi phase fluxes of higher solid/slag mass ratios is beneficial to the control of reactor linings corrosion.

Abstract: Corrosion control of glutaraldehyde biocide for 304 stainless steel in simulated cooling water system containing sulfate-reducing bacteria (SRB) was studied by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The results revealed that impedance values of stainless steel electrode increased gradually while the passive current densities decreased with the increasing concentration of glutaraldehyde. The biocide improved good anti-corrosion performance to stainless steel in bacteria system. The impedance value |Z|_0.05 increased from 19.72 kΩ·cm² to 33.77 kΩ·cm², and the passive current density reduced from 0.93 μA·cm^-2 to 0.16 μA·cm^-2 when the glutaraldehyde concentration reached 80 mg/L.

Abstract: Si-Ti coatings were prepared on the surface of T-222 alloy by fused slurry method at different temperatures (1425-1500°C). Microstructure and composition of the coatings were characterized and analysed through scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), energy dispersive X-ray spectrometry (EDS) respectively. The coating fabricated at 1450°C exhibited excellent structure compatible with high temperature oxidation resistance. Its surface is relatively smooth with few holes and cracks and the main phase on the surface is (Ti, Ta)Si that possesses outstanding corrosion resistance. Moreover, the cross-sectional structure of the coating is smooth and compact which can effectively prevent O₂ from permeation. The isothermal oxidation behaviors in pure O₂ atmosphere at 1500°C for 2h finally demonstrate that the optimum coating temperature is 1450°C.