Numerical Simulation and Process Optimization of Directional Solidification of Nb Containing High Silicon Steel

2013 ◽  
Vol 747-748 ◽  
pp. 31-37
Author(s):  
Kun Yang ◽  
Feng Ye ◽  
Yong Feng Liang ◽  
Jun Pin Lin
Keyword(s):  
Temperature Gradient ◽  
Directional Solidification ◽  
Room Temperature ◽  
Solidification Rate ◽  
Silicon Steel ◽  
Soft Magnetic ◽  
Element Analysis ◽  
Deformation Processes ◽  
Modeling And Experiments ◽  
Subsequent Deformation

Fe-6.5%Si alloy is an excellent soft magnetic material. However, the industrial production of this sheet was difficult, due to its room temperature brittleness. In order to improve its deformation performance, the directional solidification and inhibitor of Nb were investigated in this study. Rod samples of Φ6.8 mm×100 mm were used both for modeling and experiments. ProCAST-finite element analysis was employed for the modeling with a temperature gradient of 1150K/cm (from 1450°C to 300°C) for directional solidification and the drawing velocities of 10, 35, 60, and 100μm/s. Calculations were carried out on the concerning temperature gradient, solidification rate and grain growth. The results showed that small amount of Nb, with optimized drawing velocity of 60μm/s was helpful for the homogeneity of grain size, which could improve the ductility for subsequent deformation processes.

Finite Element Analysis on Directional Solidification of Al-Ni-Co Alloys

2012 ◽  
Vol 472-475 ◽  
pp. 494-498
Author(s):  
Shi Long Tian ◽  
Zhi Li Yang
Keyword(s):  
Finite Element ◽  
Temperature Gradient ◽  
Directional Solidification ◽  
Molten Steel ◽  
Solidification Front ◽  
Solidification Rate ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Element Analysis ◽  
Co Alloys

Transient temperature fields of directional solidification of Al-Ni-Co alloys were studied by employing finite element method. Temperature gradient at solidification front and solidification rate was analyzed under different pouring temperature of molten steel. The results show that with different initial pouring temperatures of molten steel, individual ratio of temperature gradient at solidification front to solidification rate soars up in the initial stage of solidification, then varies within 2000-6000°C•s•cm-2, and finally plunges down and goes together when the solidification thickness reaches 5-6cm. Simulation result is consistent with the production reality. Numerical simulation results can provide an available reference for process optimization of directional solidification of Al-Ni-Co alloys.

High Temperature Rupture Life of Nickel-Based Superalloy under Directional Solidification with High Temperature Gradient

2017 ◽  
Vol 898 ◽  
pp. 422-429 ◽  
Author(s):  
Wei Guo Zhang ◽  
Zhi Jie Liu ◽  
Song Ke Feng ◽  
Fu Zeng Yang ◽  
Lin Liu
Keyword(s):  
High Temperature ◽  
Temperature Gradient ◽  
Directional Solidification ◽  
Temperature Stress ◽  
Solidification Rate ◽  
Rupture Life ◽  
Stress Rupture ◽  
High Temperature Stress ◽  
Stress Rupture Life ◽  
Nickel Based Superalloy

The stress rupture life of DZ125 nickel-based superalloy that was prepared by directional solidification process under the temperature gradient of 500 K/cm has been studied at 900°C and 235MPa. The results showed that with the increase of directional solidification rate from 50 μm/s to 800 μm/s, the primary dendrite arm spacing reduced from 94 μm to 35.8 μm and γ' precipitates reduced and more uniformed in size. The high temperature stress rupture life of as-cast sample increased firstly and then decreased and reached its maximum at the solidification rate of 500 μm/s. The dislocation configuration of sample with refine dendritic structure after stress rupture was investigated and discovered that the dislocations in different parts of sample had different morphology and density, which indicated that the deformation of as-cast samples were uneven during high temperature stress rupture. A lot of dislocations intertwined around carbides and at the interface of γ/γ', and the dislocation networks were destroyed and the dislocations entered γ' precipitate by the way of cutting.

Alloy Elements Added in Fe-6.5wt% Si Silicon Steel and their Effect on Ductility and Magnetic Properties

2013 ◽  
Vol 750-752 ◽  
pp. 426-430
Author(s):  
Zhao Yang Cheng ◽  
Jing Liu ◽  
Wen Si Chen ◽  
Guo Dong Sun ◽  
Xi Feng Lin ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Low Temperature ◽  
Room Temperature ◽  
Silicon Steel ◽  
Soft Magnetic Properties ◽  
Action Mechanism ◽  
Soft Magnetic ◽  
Research Status

Fe-6.5wt%Si silicon steel has excellent soft magnetic properties, but its ductility in room temperature is near zero. A lot of researchers tried to improve the ductility by adding alloy elements. In this paper, we summarized the action mechanism and the content of these alloy elements according to the overseas and domestic research status. Al, B, Cr, RE, et al. improved the ductility of Fe-6.5wt%Si silicon steel in low temperature, but reduced its magnetic properties simultaneously. Ni, Ti, Mn, et al. improved the ductility of Fe-6.5wt%Si silicon steel inconspicuously.

Joining by Plastic Deformation

2018 ◽  
Vol 767 ◽  
pp. 25-41 ◽  
Author(s):  
Luis M. Alves ◽  
Carlos M.A. Silva ◽  
Paulo A.F. Martins
Keyword(s):  
Finite Element Analysis ◽  
Plastic Deformation ◽  
Room Temperature ◽  
Dissimilar Materials ◽  
Comprehensive Overview ◽  
Element Analysis ◽  
Operating Variables ◽  
Deformation Processes ◽  
Deformation Mechanics ◽  
The Individual

This paper draws from the existing processes and applications of joining by plastic deformation to a comprehensive overview of a new set of processes that have been recently developed by the authors. The presentation includes solutions for connecting tubes, sheets and tubes to sheets and provides information on the tooling systems, operating variables, deformation mechanics and workability limits. Results from analytical modelling, finite element analysis and experimentation give support to the presentation and prove the feasibility of the new joining by plastic deformation processes for connecting tubes, sheets and tubes to sheets made from dissimilar materials, at room temperature, without having to use addition materials or adhesives. The resulting joints are easy to disassembly at the end of live, thereby allowing recyclability of the individual parts.

Thermo-structural analysis of cryogenic tanks with common bulkhead configuration

2021 ◽  
pp. 095441002110247
Author(s):  
S Sumith ◽  
R Ramesh Kumar
Keyword(s):  
Structural Analysis ◽  
Temperature Gradient ◽  
Thermal Gradient ◽  
Load Transfer ◽  
Thermal Analyses ◽  
Positive Margin ◽  
Heat Transfer Analysis ◽  
Liquid Oxygen ◽  
Launch Vehicles ◽  
Element Analysis

In launch vehicles, cryogenic propulsion stages store liquid oxygen (LOX) at 76 K and liquid hydrogen (LH2) at 20 K, generally in two separate insulated tanks connected through tubular truss components. Consequently, load transfer from the LH2 tank to the LOX tank is very much localized, resulting in a nonoptimal design. This article presents an alternative single tankage design using a common bulkhead (CBH) to enhance the payload capability, which enables maintaining LH2 temperature within a specified temperature when exposed to a temperature gradient. A sandwich insulator using aramid honeycomb embedded with polyimide foam keeps the LH2 temperature within 20 ± 1 K is proposed, based on transient heat transfer analysis for 1000 s. The foam-filled honeycomb core is treated as equivalent foam in the analysis as the thermal conductivity of the core and the foam is quite close. The efficacy of the insulator is established by an experiment to measure the back wall temperature when liquid nitrogen is loaded on the top skin of the panel, and the insulator maintains a temperature gradient of 123 K for 1000 s. A good agreement is obtained between the transient finite element analysis results with experimental data. An externally insulated LOX tank configuration with an optimum length of the skirt–cylinder where the temperature reaches 80 K is arrived at based on slosh, buckling, and thermal analyses. No thermal gradient is found across the thickness of the skirt, while the thermal gradient is observed along the length of the skirt as anticipated. An integrated thermo-structural analysis of the cryo-system is carried out considering temperature-dependent material properties. A positive margin for the skirt is obtained. A payload gain of 366 kg is estimated based on the present study for the new design option with a CBH and skirt as compared to the traditional tubular truss arrangements.

scholarly journals Performance Testing and Strength Prediction of Ceramic-to-Metal Joints

1993 ◽  
Author(s):  
J. H. Selverian ◽  
Dave A. ONeil ◽  
Shinhoo Kang
Keyword(s):  
Room Temperature ◽  
Performance Testing ◽  
Strength Prediction ◽  
High Temperature Strength ◽  
Torsional Loading ◽  
Element Analysis ◽  
Failure Theory ◽  
Brazed Joints ◽  
Temperature Shear ◽  
Shrink Fit

Brazed joints were made between silicon nitride and Ni-based and Fe-based super alloys. Room temperature shear (torsion) strengths ranged from 75–242 MPa for Si3N4-to-Incoloy 909 joints and from 30–127 MPa for the Si3N4-to-Inconel 718 joints. At 500 °C the joint strength was 120 MPa while at 650°C and 950°C the joints strengths were less than 20 MPa. These low strengths at 650°C and 950°C were attributed to a reduction in the shrink-fit and to low braze strength at these high temperatures. Finite element analysis (FEA) and a probabilistic failure theory (CARES) were used to predict the joint strengths. The predicted joint strengths agreed well with measured joint strengths in torsional loading at 20°C. Torsion tests were also performed at 650°C. Aspects of the material systems, residual stresses, mechanical behavior, and strength predictions are presented. Two new braze alloys based on the Au-Ni-Cr-Fe system were used to overcome the poor high temperature strength. Joints made with these brazes had good strength (85 MPa and 35 N-m) at 650°C.

Synthesis and Luminescence Properties of Tris (8-Hydroxyquinoline) Iron Spindle-Like Structures at Room Temperature

2011 ◽  
Vol 391-392 ◽  
pp. 225-229 ◽  
Author(s):  
Qing Hong Kong ◽  
Hong Liu ◽  
Yun Long Zhang ◽  
Yong Sheng Yan
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Blue Shift ◽  
Solvent System ◽  
Iron Complex ◽  
Molecular Formula ◽  
Gravimetric Analysis ◽  
Element Analysis ◽  
Transmission Electron ◽  
Fourier Transformation Infrared Spectroscopy

Spindle-like bis (8-hydroxyquinoline) iron (FeQ3) complex has been synthesized with a facile method in a mixed solvent system at room temperature for 12 h. The molecular formula of the products is speculated by the C, H and N element analysis and thermal gravimetric analysis, and Fourier-transformation infrared spectroscopy was also utilized to measure its structure, which further confirm the molecular formula of the products. The observation of field emission scanning electron microscopy and transmission electron microscopy shows that the morphology of tris (8-hydroxyquinoline) iron complex is spindle-like structure. The photoluminescence of the products were also investigated. The results indicate that the photoluminescence emission of FeQ3spindles shows obvious blue shift contrasted with that of 8-hydroxyquinoline.

Mechanical properties of NiAl-Mo composites produced by specially controlled directional solidification

2012 ◽  
Vol 1516 ◽  
pp. 255-260 ◽  
Author(s):  
G. Zhang ◽  
L. Hu ◽  
W. Hu ◽  
G. Gottstein ◽  
S. Bogner ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Directional Solidification ◽  
Creep Resistance ◽  
Room Temperature ◽  
Growth Direction ◽  
Nominal Composition ◽  
Potential Candidate ◽  
In Situ Composites

ABSTRACTMo fiber reinforced NiAl in-situ composites with a nominal composition Ni-43.8Al-9.5Mo (at.%) were produced by specially controlled directional solidification (DS) using a laboratory-scale Bridgman furnace equipped with a liquid metal cooling (LMC) device. In these composites, single crystalline Mo fibers were precipitated out through eutectic reaction and aligned parallel to the growth direction of the ingot. Mechanical properties, i.e. the creep resistance at high temperatures (HT, between 900 °C and 1200 °C) and the fracture toughness at room temperature (RT) of in-situ NiAl-Mo composites, were characterized by tensile creep (along the growth direction) and flexure (four-point bending, vertical to the growth direction) tests, respectively. In the current study, a steady creep rate of 10-6s-1 at 1100 °C under an initial applied tensile stress of 150MPa was measured. The flexure tests sustained a fracture toughness of 14.5 MPa·m1/2at room temperature. Compared to binary NiAl and other NiAl alloys, these properties showed a remarkably improvement in creep resistance at HT and fracture toughness at RT that makes this composite a potential candidate material for structural application at the temperatures above 1000 °C. The mechanisms responsible for the improvement of the mechanical properties in NiAl-Mo in-situ composites were discussed based on the investigation results.

The Fire Resistance Performance of Double-Layer Square Pyramid Silo-Shell Structure under Fire

2013 ◽  
Vol 405-408 ◽  
pp. 2305-2310
Author(s):  
Ling Feng Gong ◽  
Yin Bai ◽  
Jian Lei Zhai
Keyword(s):  
Double Layer ◽  
Fire Resistance ◽  
Shell Structure ◽  
Room Temperature ◽  
Uniform Temperature ◽  
Global Instability ◽  
Element Analysis ◽  
Fire Temperature ◽  
Resistance Performance ◽  
Typical Temperature

With fire temperature rising, elastic modulus of steel would be reduce, which then would lead to global instability phenomenon of double-layer square pyramid silo-shell structure. In order to analyze its fire resistance performance under high fire temperature, different geometric parameters were set based on the effect factors when it operated normally at room temperature. To analyze its displacement change by conducting nonlinear finite element analysis which was under the two typical temperature rising cases including global non-uniform temperature and localized high temperature. Then, with the temperature rising, the fire resistance performance and the maxium displacement changing rule were obtained.

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