The Effect of Rare Earth Metals Alloying on the Internal Quality of Industrially Produced Heavy Steel Forgings

The paper presented the findings obtained by industrial research and experimental development on the use of rare earth metals (REMs) in the production of heavy steel ingots and their impact on the internal quality of the 42CrMo4 grade steel forging. REMs alloying was carried out after vacuuming the steel. A relatively large melting loss of cerium (about 50%) and its further decrease in casting due to reoxidation were observed. Refinement of structure and better mechanical properties of forged bar containing about 0.02 wt.% of Ce compared to that of the standard production were not achieved. The wind power shaft with content of about 0.06 wt.% of Ce showed high amount of REM inclusions, which were locally chained, and in some cases, initiated cracks. Four stoichiometrically different types of REM inclusions were detected in forgings, namely (La-Ce)2O2S + (La-Ce)O2 + SiO2 (minority); oxygen, phosphorus, arsenic, and antimony bound to lanthanum and cerium probably bonded with iron oxides La + Ce, MgO, Al2O3 a SiO2; (La-Ce)2O2S, FeO, SiO2, and CaO or CaS.

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Effect of rare-earth metals on the quality of structural steel

Metallurgist ◽

10.1007/bf00733137 ◽

1966 ◽

Vol 10 (10) ◽

pp. 574-577

Author(s):

R. P. Konovalov ◽

G. V. Bulgakov ◽

N. I. Ignatov ◽

Yu. V. Kryakovskii

Keyword(s):

Rare Earth ◽

Structural Steel ◽

Rare Earth Metals

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An Overview of Rare Earth Ores Beneficiation in Vietnam

Inżynieria Mineralna ◽

10.29227/im-2021-02-20 ◽

2021 ◽

Vol 1 (2) ◽

Author(s):

Thi Kim Dung NHU ◽

Van Luan PHAM ◽

Thi Chinh VU ◽

Van Duoc TRAN

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Magnetic Materials ◽

Animal Feed ◽

Rare Earth Metals ◽

Earth’S Crust ◽

Research Projects ◽

Essential Minerals ◽

Different Types ◽

Earth's Crust

Rare earth metals are used in electricity, electronics, nuclear, optics, space, metallurgy,superconducting and super magnetic materials, glass and ceramics, and agriculture. Some rare earthelements are added to fertilizers for crops and some trials for animal feed. Rare earth elements, exceptfor radioactive promethium, are relatively abundant in the earth's crust. Vietnam has a tremendous rareearth potential, distributed mainly in the Northwest, including Nam Xe, Dong Pao, Muong Hum, andYen Bai. There are many research projects on rare earth ores of different types globally, but the focus ismainly on the essential minerals, including monazite, xenotime, and bastnaesite. This report summarizesresearch data on rare earth ore intending to produce a general assessment of rare earth ore and itsbeneficiation technology in Vietnam.

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Effect of Rare Earth Metals on Diffusion and Porosity Deformation of Al-11Si-2Cu Cast Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1133.305 ◽

2016 ◽

Vol 1133 ◽

pp. 305-309

Author(s):

Roslee Ahmad ◽

M.B.A. Asmael

Keyword(s):

Rare Earth ◽

Cast Alloy ◽

Rare Earth Metals ◽

Optical Microscope ◽

Casting Alloy ◽

Cu Alloy ◽

Porosity Defects ◽

Rare Earth Additions

The effect of rare earth additions on diffusion and porosity deformation of Al-11Si-Cu alloy was investigated. The microstructure was characterized by optical microscope. By adding small amount of La and Ce, the porosity can be reduced. As the amount of La and Ce were increased, the porosity defects were diffused and increased in microstructure. RE intermetallic indicates Al-Cu phase interrupted the quality of Al-Si-Cu casting alloy.

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PRODUÇÃO DE DOSÍMETROS TERMOLUMINESCENTES À BASE DE MgB4O7: Dy e MgB4O7:Tm

Eclética Química Journal ◽

10.26850/1678-4618eqj.v38.1.2013.p101-108 ◽

2017 ◽

Vol 38 (1) ◽

pp. 101

Author(s):

Luiza Freire de Souza ◽

Divanízia N. Souza

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

X Rays ◽

Thermoluminescent Dosimetry ◽

Undoped Material ◽

Radiation Sources ◽

Different Types ◽

Acidic Conditions ◽

Established Technique

The thermoluminescent dosimetry (TL) is a well-established technique for the detection of ionizing radiation in hospitals, clinics, and industrial establishments where there is the need to quantify the radiation. For this practice is require the use phosphors which are sensitive to radiation. Some phosphors are already commonly used in this practice, for example, TLD-100 (LiF: Mg, Ti), CaSO4:Tm and CaSO4:Dy. A compound that was most recently introduced in dosimetry and has many advantageous features to detect neutrons, electrons and gamma is the magnesium tetraborate (MgB4O7), but the undoped material is not good for dosimetry, since signal does not show satisfactory thermoluminescence. The present work presents the analysis of the compound MgB4O7 when doped with rare earth elements, thulium (Tm) and dysprosium (Dy). The production of MgB4O7: Dy and MgB4O7: Tm occurred under acidic conditions. Following the process of crystal growth, several tests were made on phosphors produced to verify the quality of materials as TL dosimeter. Initially, was made the identification of the crystalline phases found in the material, using the technique of X-ray diffractometry, and then were evaluated and compared the TL emission curves of the crystals with two different types of dopants, to this, the samples were irradiated with different radiation sources: 137Cs (0,66 MeV), 60Co (1.25 MeV) and X-rays (0.41 MeV) and based on the results was evaluated the energy dependence of phosphors. Another characteristic analyzed, was the decay of TL signal for the material (fading). The results show that the material can be an excellent TL dosimeter when doped with rare earth elements Dy and Tm.

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