scholarly journals Experimental – Numerical Analysis of Stress State in Front of the Crack Tip of Modified and Unmodified G17CrMo5-5 Cast Steel by Rare Earth Metals in a Brittle-Ductile Transition Region

2016 ◽  
Vol 61 (2) ◽  
pp. 1175-1181
Author(s):  
I. Dzioba ◽  
R. Pala ◽  
J. Kasinska
Keyword(s):  
Fracture Toughness ◽  
Rare Earth ◽  
Stress State ◽  
Numerical Analysis ◽  
Crack Extension ◽  
Cast Steel ◽  
Rare Earth Metals ◽  
Initial Moment ◽  
Brittle Ductile Transition

Abstract In the paper presented experimental data and numerical analysis of stress distribution in front of the crack of two melts of low-alloy G17CrMo5-5 cast steel-modified (M) by rare earth metals and original, unmodified (UM) in the temperature range, according to the brittle-ductile transition region. Experimental tests include determination of the tensile properties and fracture toughness characteristics for the UM and M cast steel. Numerical analysis includes determination of stress distribution in front of the crack at the initial moment of the crack extension. In the numerical computations, experimentally tested specimens SEN(B) were modeled. The true stress-strain curves for the UM and M cast steel were used in the calculation. It was shown that the maximum of the opening stresses at the initial moment of the crack extension occurs in the axis of the specimens and reaches similar level of about 3.5σ0 for both UM and M cast steel. However, the length of the critical distance, measured for stress level equal 3σ0, is great for the M in comparison to the UM cast steel. Also was shown that the UM cast steel increased the level of the stress state triaxiality parameters that resulted in a decrease of fracture toughness.

scholarly journals The FEM Analysis of Stress Distribution in front of the Crack Tip and Fracture Process in the Elements of Modified and Unmodified Cast Steel G17CrMo5-5

2016 ◽  
Vol 10 (3) ◽  
pp. 201-206
Author(s):  
Robert Pała ◽  
Ihor Dzioba
Keyword(s):  
Stress Distribution ◽  
Cleavage Fracture ◽  
Crack Extension ◽  
Cast Steel ◽  
Experimental Studies ◽  
Fem Analysis ◽  
Initial Moment ◽  
Stress Distributions ◽  
Calculated Stress

Abstract The article presents influence of modification of the low-alloy cast steel G17CrMo5-5 by rare earth metals on stress distribution in front of the crack at the initial moment of the crack extension. Experimental studies include determination of strength and fracture toughness characteristics for unmodified (UM) and modified (M) cast steel. In the numerical computations, experimentally tested specimens SEN(B) were modelled. The true stress–strain curves for the UM and M cast steel are used in the calculation. The stress distributions in front of the crack were calculated at the initial moment of the crack extension. On the basis of data on the particle size inclusions in the UM and M cast steel, and the calculated stress distributions was performed an assessment of the possibility of the occurrence of cleavage fracture. The analysis results indicate that at room temperature for the UM cast steel, there is a possibility of cleavage fracture, while for the M cast steel occurrence of cleavage fracture is negligible.

scholarly journals The Influence Of The Rare Earth Metals Modification On The Fracture Toughness Of G17CrMo5-5 Cast Steel At Low Temperatures

2015 ◽  
Vol 60 (2) ◽  
pp. 773-777 ◽  
Author(s):  
I. Dzioba ◽  
J. Kasińska ◽  
R. Pała
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Rare Earth ◽  
Low Temperatures ◽  
Cast Steel ◽  
Rare Earth Metals ◽  
Positive Influence ◽  
Reference Temperature ◽  
Brittle To Ductile Transition ◽  
The Rare Earth

Abstract This paper presents the influence of the rare earth metals (REM) modification on mechanical properties and fracture toughness of G17CrMo5-5 cast steel at low temperatures. The REM was in the form of mishmetal. The research has been performed on serial (several) industrial melts. The fracture toughness values of unmodified and modified cast steel at the temperature range from −80°C to 20°C were tested. The reference temperatures of the brittle-to-ductile transition, TQ, for both unmodified and modified cast steel were determined. The positive influence of the modification by REM on the fracture toughness and the reference temperature TQ are shown.

Dc arc emission analysis of rare earth metals and their oxides with sorption preconcentration of impurities

2018 ◽  
Vol 84 (11) ◽  
pp. 9-14
Author(s):  
E. S. Koshel ◽  
V. B. Baranovskaya ◽  
M. S. Doronina
Keyword(s):  
Rare Earth ◽  
Rare Earth Metals ◽  
Analytical Signal ◽  
Graphite Powder ◽  
Atomic Emission ◽  
Standard Samples ◽  
Emission Analysis ◽  
Sorption Preconcentration ◽  
Sample Shape

The analytical capabilities of arc atomic emission determination of As, Bi, Sb, Cu, Te in rare earth metals (REM) and their oxides after preparatory group concentration using S,N-containing heterochain polymer sorbent are studied on a high-resolution spectrometer “Grand- Extra” (“WMC-Optoelectron-ics” company, Russia). Sorption kinetics and dependence of the degree of the impurity extraction on the solution acidity are analyzed to specify conditions of sorption concentration. To optimize the procedure of arc atomic emission determination of As, Bi, Sb, Cu, and Te various schemes of their sorption preconcentration and subsequent processing of the resulted concentrate with the addition of a collector at different stages of the sorption process have been considered. Graphite powder is used as a collector in analysis of rare earth oxides due to universality and relative simplicity of the emission spectrum. Conditions of analysis and parameters of the spectrometer that affect the analytical signal (mass and composition of the sample, shape and size of the electrodes, current intensity and generator operation mode, interelectrode spacing, wavelengths of the analytical lines) are chosen. The evaporation curves of the determinable impurities were studied and the exposure time of As, Bi, Sb, Cu, and Te in the resulted sorption concentrate was determined. Correctness of the obtained results was evaluated using standard samples of the composition and in comparisons between methods. The results of the study are used to develop a method of arc chemical-atomic emission analysis of yttrium, gadolinium, neodymium, europium, scandium and their oxides in a concentration range of n x (10-2 - 10-5) wt.%.

DETERMINATION OF THE RARE EARTH METALS IN THE RED MUD FOR POSSIBLE UTILIZATION

2018 ◽  
Vol 17 (8) ◽  
pp. 2001-2009
Author(s):  
Tatjana Juzsakova ◽  
Akos Redey ◽  
Le Phuoc Cuong ◽  
Zsofia Kovacs ◽  
Tamas Frater ◽  
...  
Keyword(s):  
Rare Earth ◽  
Red Mud ◽  
Rare Earth Metals ◽  
The Rare Earth

Determination of Fracture Toughness and K-R Curve for 2524-T3 Aluminum Alloy

2011 ◽  
Vol 291-294 ◽  
pp. 1039-1042
Author(s):  
Wei Xie ◽  
Shao Wei Tu ◽  
Qi Qing Huang ◽  
Ya Zhi Li
Keyword(s):  
Fracture Toughness ◽  
Aluminum Alloy ◽  
Stress Fracture ◽  
Test Data ◽  
Plane Stress ◽  
Crack Extension ◽  
Room Temperature ◽  
Mode I ◽  
Average Value

In the present work, the resistance to crack extension of 2524-T3 aluminum alloy under Mode I loading was studied by using the middle-cracked tension M (T) specimens. The curve, plane-stress fracture toughness and apparent plane-stress fracture toughness were calculated by test data. The average value of measured fracture toughness at room temperature was 161 MPam1/2. The results and conclusions can be referred in airplane skin design.

Determination of admixtures of high-melting metals in rare-earth metals and their compounds

2012 ◽  
Vol 67 (4) ◽  
pp. 340-348 ◽  
Author(s):  
V. K. Karandashev ◽  
K. V. Zhernokleeva ◽  
A. N. Turanov ◽  
V. B. Baranovskaya ◽  
Yu. A. Karpov
Keyword(s):  
Rare Earth ◽  
Rare Earth Metals ◽  
High Melting

scholarly journals An Assessment of Natural Radioactivity in the Namxe Rare Earth Deposit, Laichau Province, Vietnam

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 602
Author(s):  
Quang Van Phan ◽  
Trung Thanh Dao ◽  
Phuong Nguyen ◽  
Dinh Huan Trinh ◽  
Thomas Heinig
Keyword(s):  
Rare Earth ◽  
Rare Earth Metals ◽  
Environmental Issues ◽  
Water Usage ◽  
Radioactive Materials ◽  
Mining Site ◽  
Naturally Occurring ◽  
The Rare Earth

The Namxe rare earth deposit belongs to Namxe commune, Phongtho district, Laichau province, which has a large resource of rare earth metals in Vietnam. The case study presents an assessment of the naturally occurring radioactivity for the rare earth prospect Namxe for future monitoring purpose, especially for the case of an actual mine in the area. The investigation included determination of radioactivity in the air, soil, water, and plants. The results showed that although the water usage is harmless, radioactive materials were found in soils and plants in considerable amounts. The mapping of these features revealed two zones of elevated radioactivity, one of which even bearing health risks according to several health standards. These zones correspond well with the rare earth deposit area. From the study, safety, health, and environmental issues could be deduced, including a risk assessment for the area and the intended mining site.

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