Advanced Materials Research Vols. 690-693

Abstract: The desulphurization kinetics in ladle refining was analyzed, and the restrictive link for the desulfurization was selected based on previous research. Then the kinetics of desulfurization model in LF refining was developed and the empirical formula of sulfur ratio was summarized. The result by calculated shows that there is a good linear correlation between desulfurization rate and time, and the mass transfer coefficient D=3.79x10^-5m/min.

Abstract: Using scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS), the morphology observations and composition analtyses of a T23 steel oxidized in water vapor for 10~150min at 600°C were investigated, to study the initial formation mechanism. The result showed that the initial oxidation film was changed from acicular to flake shape. The second oxidation film layer appeared after oxidation for 40 min, and obvious double oxidation film structure was formed after 150 min with inner Cr-rich protective isometric crystal and outer Fe primarily columnar crystal.The oxide was Fe-rich phase in the whole oxidation process.

Abstract: This paper proposed significance and urgency of constructing steelmaking MES on analysing the informationization status of Pangang Group. And addressed the implementation of steelmaking MES for Pangang Group. The steelmaking MES adopted multi-tier architecture which included presentation layer, application server layer and data layer. The presentation layer mainly fulfilled user permission and display of GUI. Application server layer mainly fulfilled system function such as access control, data subscribe/publish, object mapping, database access, components management. Business logic on the application server executed storage management, plan management, process monitoring, actual production management and quality control etc. The implementation of this system significantly improved the management level of steel plant, optimized the productive process and reduced the production cost.

Abstract: In this study, three kinds of rolled wire rod materials constantly used on screws and bolts are concerned. The relation among mechanical properties, phase ratios, micro-structures and grain sizes is investigated on the wire materials of low carbon steels and extra low carbon steels. Also the Electron Microscope and Energy Spectrum analysis are applied to distinguish the type of Precipitation phase. The results are shown that the precipitation phase of titanium nitrides and titanium carbides exist in the extra low carbon steel so that the hardness ratio of the wire materials with extra low carbons after cold forming is higher than that of the wire materials with low carbons for around 10%. In addition, The wire rod materials with course ferrite grains mainly added by titanium elements in extra low carbon steels could be made as the wire materials for cold processing and it still kept good ductility not necessary to be softened under heat treatment. So in the research of function comparisons, to save cost expenses through cold forming without annealing process is expected.

Abstract: The effect of temper temperature and duration on the microstructure and mechanical properties of new-type ultrahigh strength Fe-Ni-Co alloy was investigated with by mechanics performance testing and TEM. The results showed that the maximum ultimate tensile strength could reach 2230MPa after temper near 470°C due to the precipitation of coherent zones of fine carbides. With tempering time extended, the strength was cut down by the M2C carbides coarsening and the decreased coherency with matrix.

Abstract: This paper presents the technology background, the types and basic compositions of corrosion-resistant alloys for tubings and casings in oil and gas wells, modes of corrosion and influence factors for corrosion-resistant alloy, corrosion-resistant alloys material selection for tubings and casings in oil and gas wells. And the technology above has a good practicality for application .

Abstract: High temperature oxidation of ferritic stainless steel 21Cr-0.6Mo-Nb-Ti was carried out isothermally at 1100 oC under different water vapour content conditions in an electrical furnace. Water vapour does accelerate the formation of oxide scale of stainless steel 21Cr-0.6Mo-Nb-Ti, however, it is not significant. Some oxide grains consist of spinel crystal structure, which should be spinel Manganese Chromite. In dry air atmosphere, the grain of the spinel is more and bigger than that in wet air. No breakaway oxidation occurs in the experiment indicating that 21Cr-0.6Mo-Nb-Ti has very high oxidation resistance, which might be contributed by the formation of MnCr₂O₄ and compact protective chromia. In addition, continuous silica formed along and accumulated at the oxide metal interface performs like a diffusion barrier.

Abstract: The element W, Mo with paremagnetism and grain refinement is selected according to the theory of magnetostrictive and fine grain strengthening method. The sample with low coefficient of thermal expansion (CTE) and high strength are made by W and Mo alloying of Fe-Ni36, forging and heat treatment. The mechanism of low coefficient of thermal expansion and high strength is analyzed by means of the results of Chemical analysis, metallographic and scanning electron microscopy, grain size, micro-hardness and CTE testing. The result shows: the strength of matrix is improved by W and Mo alloying, the CTE is lower at the same time.

Abstract: This study investigated the effect of pre-oxidation on the high-temperature oxidation behavior of Fe-Cr-Al powder porous metal. Using the powder metallurgy process, Fe-Cr-Al powder porous metals with and without pre-oxidation were manufactured. 24-hour TGA tests were conducted at three different temperatures: 900°C, 1000°C, and 1100°C. The high temperature oxidation results showed that pre-oxidized powder porous metal had even higher levels of oxidation resistance compared to that of porous metal without pre-oxidation regardless of the oxidation temperature. The weight gain of pre-oxidized porous metal (0.123%) was lowest at oxidation temperature of 900°C. In contrast, the weight gain of porous metals significantly increased at 1100°C. In the porous metals 900°C and 1000°C oxidized specimen, oxides such as Al₂O₃ and Cr₂O₃ were mainly observed. Porous metals oxidation specimen at 1100°C also revealed the presence of Fe-based oxides in large quantities in addition to the oxides formed at lower temperature.

Abstract: The magnetic hysteresis loop is a significant performance of ferromagnetic material. The different-size specimens were fabricated and studied on the basis of magnetomechanical coupling tests. The curve of relationship between model size and magnetization intensity is obtained and hysteretic curve is described in the different conditions. The results indicate that the influencing law is reflected based on size effect of model specimens and performance of magnetic hysteresis and magnetization intensity. The results indicate that the size of Q235 steel model specimens is considerably influential in the magnetic hysteresis loop and magnetization, which accounts for an evident size effect.