scholarly journals Effects of CeO2 on Viscosity, Structure, and Crystallization of Mold Fluxes for Casting Rare Earths Alloyed Steels

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 333 ◽  
Author(s):  
Zeyun Cai ◽  
Bo Song ◽  
Longfei Li ◽  
Zhen Liu ◽  
Xiaokang Cui
Keyword(s):  
Melting Temperature ◽  
Rail Steel ◽  
X Ray Diffraction ◽  
Viscous Property ◽  
X Ray ◽  
Rare Earth Alloy ◽  
Steel Continuous Casting ◽  
Mold Fluxes ◽  
Cylinder Method ◽  
Heavy Rail

The CaO-Al2O3-based mold fluxes are proposed for the Ce-bearing heavy rail steel continuous casting because of the low reactivity. Effects of CeO2 on the melting temperature, the viscous property, and the crystallization behavior of the CaO-Al2O3-Li2O-B2O3 mold fluxes were studied using hemisphere melting point method, rotating cylinder method, and X-ray diffraction (XRD) in the present work. The microstructure of the mold fluxes was analyzed by Fourier-transform infrared spectroscopy (FTIR). The results revealed that the addition of CeO2 would increase the melting temperature, but decrease the viscosity at each temperature due to its influence on increasing the depolymerization of the mold fluxes at high temperature. The precipitation of CaO was restrained and CaCeAlO4 generated with increasing CeO2 content since the crystal phases were affected by the microstructure of the melts. The change of the crystalline phases in mold fluxes influences the break temperature and the viscosity of the mold fluxes below the break temperature. These results obtained can provide guidelines for designing new mold fluxes for casting rare earth alloy heavy rail steels.

scholarly journals Prediction on the spatial distribution of the composition of inclusions in a heavy rail steel continuous casting bloom

2020 ◽  
Vol 9 (3) ◽  
pp. 5648-5665 ◽  
Author(s):  
Qiang Ren ◽  
Yuexin Zhang ◽  
Lifeng Zhang ◽  
Jujin Wang ◽  
Yanping Chu ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Continuous Casting ◽  
Rail Steel ◽  
Steel Continuous Casting ◽  
Heavy Rail ◽  
Heavy Rail Steel

Preparation and Characterization of V-Type Amylose-Hexanol Complex

2011 ◽  
Vol 422 ◽  
pp. 641-645 ◽  
Author(s):  
Liu Zhi Yang ◽  
Xin Xin Xiao ◽  
Miao Miao Zheng ◽  
Yin Long Xu ◽  
Yan Qi Liu
Keyword(s):  
Melting Temperature ◽  
Particle Diameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solvent Method ◽  
Aqueous Solvent ◽  
Alcohol Solvent ◽  
Alcohol Solvents ◽  
Scanning Electron

In this paper, B-type microcrystalline starch made a combination with hexanol in the case of water and alcohol as solvent respectively, V-type amylose-hexanol complexes were prepared. Obtained V-type amylose-hexanol complexes were characterized with scanning electron microscopy, X-ray diffraction, differential scanning calorimete. The results showed that using the preparation of water and alcohol solvents, obtained V-type amylose-hexanol complexes were hydrates and anhydrous crystal respectively. Hydrate crystal’s particles adhesion were serious, the particle diameter of anhydrous crystalline was 0.5~1μm, the crystallinity of both were above 70%. The V-type complexes prepared by aqueous solvent method and alcohol solvent method had almost the same melting temperature, the melting temperature of hydrates and anhydrous forms crystal were 70.7°C and 69.36°C.

Effect of Ce2O3 and CaO/Al2O3 on the Phase, Melting Temperature and Viscosity of CaO-Al2O3-10 Mass% SiO2 Based Slags

2014 ◽  
Vol 33 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Chengchuan Wu ◽  
Guoguang Cheng ◽  
Hu Long
Keyword(s):  
Melting Temperature ◽  
Slag Composition ◽  
Slag System ◽  
Refining Process ◽  
Phase Identification ◽  
X Ray Diffraction ◽  
Green Color ◽  
X Ray ◽  
Point Detector ◽  
O Phase

AbstractThe melting temperature and viscosity of CaO-Al2O3-10 mass% SiO2 based slag system with various concentrations of Ce2O3 have been studied using the melting point detector and the rotating crucible viscometer. And X-ray diffraction analysis has been used for phase identification. The results show that cerium is stable in Ce3+ state existing mainly as CeAlO3 and Ce4.67(SiO4)3O phase in slags and CeAlO3 phase appears in green color. The melting temperature gently decreases with Ce2O3 additions in 1.57 of CaO/Al2O3. Moreover, the melting temperature increases first and then decreases with the increasing of CaO/Al2O3 from 1.17 to 1.52 at 4.47 mass% Ce2O3. In addition, at 1.57 of CaO/Al2O3, the viscosity increases at the beginning and then decreases with the increasing Ce2O3 content from 4.39 to 11.48 mass%. Furthermore, at 4.47 mass% Ce2O3, the viscosity decreases at the first and then increases with the increasing CaO/Al2O3 from 1.17 to 1.52. Meanwhile, from the slopes of the Arrhenius relationship for viscosity, the activation energy range of viscous flow is from 179.07 to 433.70 kJ/mol. On the basis of these results, slag composition of 45.64 mass% CaO-39.02 mass% Al2O3-10.73 mass% SiO2-3.83 mass% Ce2O3 is melting temperature of 1361 °C and viscosity of 0.398 Pa·s (1500 °C), which has superiority and is more suitable for the actual refining process.

Investigation on the Preparation Processes of Cu-Bi Master Alloy

2011 ◽  
Vol 335-336 ◽  
pp. 841-844 ◽  
Author(s):  
Li Na Zhang ◽  
Bai Xiong Liu
Keyword(s):  
Electron Microscopy ◽  
Melting Temperature ◽  
Master Alloy ◽  
Holding Time ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Two Phases ◽  
Fluorescence Analyzer ◽  
Scanning Electron

The Microstructure of Cu-Bi master alloy with different melt processes, such as different melting temperature and holding time, was observed by PHILIPS-XL30 scanning electron microscopy (SEM); phase analysis was conducted by Miniflex X-ray diffraction(XRD); Magix(PW2424) X-ray fluorescence analyzer(XRF) was used to analyze chemical compositions of Cu-Bi master alloy. The results show that there are Cu and Bi two phases in the Cu-Bi master alloy; The yielding rate of bismuth decreases with the rising melting temperature. It decreases slowly between 1100 °C to 1150 °C,while it decreases rapidly between 1150 °C to 1200 °C.The bismuth particles in the Cu-Bi master alloy prepared at 1100 °C are much larger than those prepared at 1150 °C,while the size of bismuth particles change little from 1150 °C to 1200 °C. So the better melting temperature of preparing Cu-Bi master alloy is 1150 °C.The yielding rate of bismuth decreases with the holding time increasing. But when the holding time is too short, there are large bismuth particles in Cu-Bi alloy .So the better holding time is 120s.

Nature of Stark Rubber

1955 ◽  
Vol 28 (4) ◽  
pp. 1007-1020 ◽  
Author(s):  
Donald E. Roberts ◽  
Leo Mandelkern
Keyword(s):  
Natural Rubber ◽  
Melting Temperature ◽  
Melting Behavior ◽  
X Ray Diffraction ◽  
Equilibrium Melting Temperature ◽  
X Ray ◽  
Melting Temperatures ◽  
Controlled Conditions ◽  
Previous Assignment ◽  
Diffraction Patterns

Abstract The melting behavior and x-ray diffraction patterns of four different samples of stark rubber have been investigated. The melting temperatures, 39° to 45.5° C, are substantially higher than that observed for natural rubber crystallized by cooling. The x-ray diffraction patterns indicate that the crystallites in stark rubber are oriented. This observation can explain the higher melting temperatures. Thus, the previous assignment of an equilibrium melting temperature, 28° (±1°) C, to unoriented crystalline natural rubber is shown to be appropriate. Several different methods that have been used successfully in preparing stark rubber under controlled conditions in the laboratory are outlined.

Influence of Nb2O5 and basicity on the viscosity and structure of CaO-SiO2-Nb2O5-CeO2-CaF2 slag system

2020 ◽  
Vol 117 (3) ◽  
pp. 307
Author(s):  
Zhuang Ma ◽  
Zengwu Zhao ◽  
Wentao Guo ◽  
Zhi Wang
Keyword(s):  
Activation Energy ◽  
Slag System ◽  
Rotating Cylinder ◽  
Degree Of Polymerization ◽  
X Ray Diffraction ◽  
Structural Units ◽  
X Ray ◽  
Reducing Atmosphere ◽  
Bayan Obo ◽  
Cylinder Method

In order to utilize niobium concentrate of Bayan Obo effectively, the effect of Nb2O5 and basicity on the viscosity of CaO-SiO2-Nb2O5-5.0 wt.% CeO2-5.0 wt.% CaF2 slag system was studied from 1653 to 1813 K in reducing atmosphere by rotating cylinder method. For the same condition, the as-quenched samples were investigated through X-ray diffraction and Raman spectroscopy. The results show that the viscosity, break temperature and activation energy of viscous flow decrease with the increase of Nb2O5 and basicity. Raman spectra show that the Nb4+ ions exist in the form of [NbO6] octahedron with different distortion and little [NbO4] tetrahedron in the slags. The Nb2O5 addition and basicity lower the degree of polymerization, where the complex Si-O network is depolymerized into simple structural units.

Crystallization in Unstretched Rubber. Microscopic Study in Polarized Light

1951 ◽  
Vol 24 (3) ◽  
pp. 550-556
Author(s):  
H. N. Campbell ◽  
M. D. Allen
Keyword(s):  
Low Temperature ◽  
Physical Properties ◽  
Melting Temperature ◽  
Microscopic Study ◽  
Room Temperature ◽  
Polarized Light ◽  
X Ray Diffraction ◽  
X Ray ◽  
Limited Mobility ◽  
Sensitive Method

Abstract Since many elastomers indicate by their physical properties that crystallization occurs even when such crystallization is not detectable by x-ray diffraction, a direct microscopic study in polarized light was undertaken. This study confirms the presence of such crystallinity not only in rubber but also in polybutadiene and some low-temperature copolymers. Furthermore, the same crystal pattern is reproduced on melting and refreezing provided the intermediate melting temperature is not too high. This indicates that x-ray diffraction is not a very sensitive method for detecting small amounts of crystallinity in high polymers. The reproduction of the crystal pattern on refreezing shows that the molecular segments have limited mobility even at room temperature; this may require revision of current theories of the origin of retractive forces in elastomers.

Resonance-enhanced magnetic X-ray diffraction from a rare-earth alloy

1994 ◽  
Vol 6 (12) ◽  
pp. 2409-2422 ◽  
Author(s):  
D B Pengra ◽  
N Thoft ◽  
M Wulff ◽  
R Feidenhans'l ◽  
J Bohr
Keyword(s):  
Rare Earth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rare Earth Alloy
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