Articoli di riviste: "Remelting process"

1

Mróz, M., W. Orłowicz e M. Tupaj. "Geometry of Remeltings and Efficiency of the Surface Remelting Process Applied to Cobalt Alloy Castings". Archives of Foundry Engineering 13, n. 2 (1 giugno 2013): 95–98. http://dx.doi.org/10.2478/afe-2013-0044.

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Abstract The paper summarises results of measurements of remelting area geometry, thermal efficiency and melting efficiency characterising the surface remelting process applied to castings of MAR-M-509 cobalt alloy. The remelting process was carried out with the use of GTAW (Gas Tungsten Arc Welding) method in protective atmosphere of helium, at the electric current intensity in the range from 100 A to 300 A, and the electric arc scanning velocity vs in the range from 200 mm/min to 800 mm/min. The effect of current intensity and electric arc scanning velocity on geometrical parameters of remeltings, thermal efficiency, and melting efficiency characterising the remelting process has been determined.

2

Trytek, Andrzej Stanisław, Mirosław Tupaj, Ján Majerník, Štefan Gašpár, Wiktoria Zbyrad-Kołodziej e Karol Łysiak. "Surface Remelting of Mold Inserts Made of NC11 Steel". Journal of Casting & Materials Engineering 4, n. 1 (31 marzo 2020): 9–15. http://dx.doi.org/10.7494/jcme.2020.4.1.9.

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In the study presented in this paper, the effect of a concentrated heat stream on geometry, microstructure, and hardness of superficial remeltings on NC11 steel is examined. The material is used for disposable mold inserts exposed to intensive abrasive wear in the course of the press-molding of hard aggregate stampings for refractory bricks. As a result of local remelting, the hardness of the steel surface increased and its microstructure was altered. Macro- and microstructure of the remelted areas was examined with the use of optical microscopy and measurements of remelting area geometry were carried out for different parameters of the remelting process. Hardness measurements were taken in the remelting area and in the heat-affected zone. The state of stress in the material before remelting and in the remelted area was also evaluated.

3

Arh, Boštjan, Bojan Podgornik e Jaka Burja. "Electroslag remelting: A process overview". Materiali in tehnologije 50, n. 6 (12 dicembre 2016): 971–79. http://dx.doi.org/10.17222/mit.2016.108.

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Ding, Wan Wu, Jiang Tao Zhu, Wen Jun Zhao e Tian Dong Xia. "Microstructure Evolution of Al-Ti-C Alloy Wires during Remelting Process". Advanced Materials Research 652-654 (gennaio 2013): 1119–23. http://dx.doi.org/10.4028/www.scientific.net/amr.652-654.1119.

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The regular pattern of evolution of TiC and TiAl3 during the remelting process of Al-Ti-C alloy wires was analyzed and the impact mechanism was discussed. The results show that: when the temperature of the remelting mass is at 730°C, with the increase of the heat preservation time of remelting, the degree of agglomeration of the original dispersed TiC will increase, and they are pushed toward crystal boundaries by α-Al during the solidification process, while TiAl3 will dissolve, aggregate, and grow. When the remelting temperature is at 1000°C, as the heat preservation time increases, not only the agglomeration degree of TiC increases significantly compared to that at 730 °C and the sizes and shapes of TiAl3 change significantly as well. The morphology of TiAl3 will change from being lump-and-short-rod-like to needle-and-flake-like. Before and after remelting, the Al-Ti-C alloys are both composed of TiAl3 and TiC, with no other phases formed.

5

Šturm, Roman, e Janez Grum. "Influence of Laser Remelting Process on Strain and Residual Stresses in Nodular Iron". Materials Science Forum 681 (marzo 2011): 188–93. http://dx.doi.org/10.4028/www.scientific.net/msf.681.188.

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The present paper deals with residual stress and strain changes in thin flat specimens of nodular cast iron during laser remelting process. In laser remelting process of a workpiece we have used several laser beam passages across the workpiece surface. The state of internal stress in the workpiece changes because of different ways of guiding the laser beam across the workpiece surface, and consequently strain of the workpiece may occur. In the process of gradual remelting of the specimen surface, i.e. during its heating and cooling, volume changes in the specimen surface layer occur due to thermal and microstructural changes. To find out more about volume changes in the thin surface layer of specimens, the latter were monitored by measuring the strain at the lower side of the specimens during and after the remelting process, and also by residual stress measurement in the thin surface layer. The results obtained confirm that the laser remelting process could be successfully optimised on the basis of knowing the residual stresses and the strain generated during the remelting process.

6

Yi, Rong Xi, Xiao Qiu Zheng, Shi Kun Xie e Xiu Yan Guo. "Study on the Remelting Process of Rare Earth Al-4.5Cu". Applied Mechanics and Materials 66-68 (luglio 2011): 1854–57. http://dx.doi.org/10.4028/www.scientific.net/amm.66-68.1854.

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The influences of heating temperature and holding time on the microstructures were investigated during the semi-solid remelting process of rare earth Al-4.5Cu alloy. The evolution mechanism of crystal organization was discussed. Experiments show that the heating temperature and holding time are very important to the grain size and uniformity. It is the most suitable parameters, as heating temperature is 630°C and holding time is 20 minutes, to remelting process. During the remelting process, grain mergering and Ostwald growing up is the main mechanism of change on microstructures.

7

Guo, Hua Feng, Tao Sun, Zhi Li e Ju Li Li. "Influence of Process Parameters on Temperature Field in Laser Remelting Coating Prepared by Plasma Spraying on Titanium Alloy Surface". Applied Mechanics and Materials 197 (settembre 2012): 802–7. http://dx.doi.org/10.4028/www.scientific.net/amm.197.802.

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In order to research the effect of process parameters on temperature field evolution in laser remelting coating prepared by plasma spraying on titanium alloy surface，the finite element model of laser multi-tracks remelting temperature field was established based on ANSYS, and remelting temperature field was analyzed. The analysis results show that: under certain scanning velocity and laser spot diameter, too small laser power can't achieve metallurgical combination between coating and substrate; the effect on temperature field of scanning velocity was smaller than laser power; the influence on molten pool center temperature and remelting width of spot diameter is bigger; preheating coating and substrate can be effectively balance remelting process temperature field, thereby reducing the thermal stress and coating cracks appear chance.Through the calculation model can master the evolution of the temperature of lasre remelting process and can provide the theory basis for process parameter selection and optimization.

8

INOUYE, Michio. "Present Status of Electroslag Remelting Process". Tetsu-to-Hagane 73, n. 2 (1987): 233–41. http://dx.doi.org/10.2355/tetsutohagane1955.73.2_233.

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DONG, Yan-wu, Zhou-hua JIANG e Zheng-bang LI. "Mathematical Model for Electroslag Remelting Process". Journal of Iron and Steel Research, International 14, n. 5 (settembre 2007): 7–30. http://dx.doi.org/10.1016/s1006-706x(07)60065-x.

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Dong, Yan-wu, Zhou-hua Jiang e Zheng-bang Li. "Mathematical Model for Electroslag Remelting Process". Journal of Iron and Steel Research International 14, n. 5 (maggio 2007): 7–12. http://dx.doi.org/10.1016/s1006-706x(08)60042-4.

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Ishikawa, Toshiji, Takeshi Yamamura, Takashi Ohtsuka, Tsuyomi Taniyama e Tomio Inukai. "New technology of electroslag remelting process." DENKI-SEIKO[ELECTRIC FURNACE STEEL] 60, n. 2 (1989): 185–94. http://dx.doi.org/10.4262/denkiseiko.60.185.

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Murgas, M., e M. Pokusova. "The solidification process in electroslag remelting". Welding International 7, n. 4 (gennaio 1993): 327–31. http://dx.doi.org/10.1080/09507119309548401.

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Zhu, Jun Feng, Wei Feng Xiao, Gang Liu e Shu Lin Wang. "The Property Comparison of Coating Prepared by Oxygen-Acetylene Spray Welding Technology and High-Frequency Induction Remelting Technology". Advanced Materials Research 652-654 (gennaio 2013): 1805–9. http://dx.doi.org/10.4028/www.scientific.net/amr.652-654.1805.

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Ni60A coating is obtained by oxygen-acetylene spray welding and high-frequency induction remelting process. Coating Surface, interface between matrix and coating, microhardness and wear resistance are investigated. The results show that both of the processes can achieve coating metallurgically bonded to matrix. But microhardness and wear resistance of Ni60A coating obtained by high-frequency induction remelting process are superior to those of Ni60A coating obtained by oxygen-acetylene spray welding process. At the same time, coating surface by high-frequency induction remelting process is of more brightness owing to less oxide skin. In order to more effectively prevent the hard phase from oxidation, the quartz glass pipe and inert gas should be considered to use in high-frequency induction remelting process.

14

Soffel, Fabian, Yunong Lin, Dominik Keller, Sergei Egorov e Konrad Wegener. "Laser Remelting Process Simulation and Optimization for Additive Manufacturing of Nickel-Based Super Alloys". Materials 15, n. 1 (27 dicembre 2021): 177. http://dx.doi.org/10.3390/ma15010177.

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Nickel-based super alloys are popular for applications in the energy and aerospace industries due to their excellent corrosion and high-temperature resistance. Direct metal deposition (DMD) of nickel alloys has reached technology readiness for several applications, especially for the repair of turbomachinery components. However, issues related to part quality and defect formation during the DMD process still persist. Laser remelting can effectively prevent and repair defects during metal additive manufacturing (AM); however, very few studies have focused on numerical modeling and experimental process parameter optimization in this context. Therefore, the aim of this study is to investigate the effect of determining the remelting process parameters via numerical simulation and experimental analyses in order to optimize an industrial process chain for part repair by DMD. A heat conduction model analyzed 360 different process conditions, and the predicted melt geometry was compared with observations from a fluid flow model and experimental single tracks for selected reference conditions. Subsequently, the remelting process was applied to a demonstrator repair case. The results show that the models can well predict the melt pool shape and that the optimized remelting process increases the bonding quality between base and DMD materials. Therefore, DMD part fabrication and repair processes can benefit from the remelting step developed here.

15

Xu, Lianyong, Yaqing Zhang, Lei Zhao, Wenjing Ren e Yongdian Han. "Performance Improvement for the CuCrZr Alloy Produced by Laser Powder Bed Fusion Using the Remelting Process". Materials 17, n. 3 (27 gennaio 2024): 624. http://dx.doi.org/10.3390/ma17030624.

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Owing to the high optical reflectivity of copper powder, the high-performance fabrication of copper alloys in the laser additive manufacturing (AM) field is problematic. To tackle this issue, this study employs the remelting process during laser powder bed fusion AM to fabricate defect-free and high-performance CuCrZr alloy. Compared to the non-remelting process, the remelting process yields finer grains, smaller precipitates, denser dislocations, and smaller dislocation cells. It realizes not only the dense molding of high laser reflectivity powders but also excellent mechanical properties and electrical conductivity (with an ultimate tensile strength of 329 MPa and conductivity of 96% IACS) without post-heat treatment. Furthermore, this study elucidates the influence of complex thermal gradients and multiple thermal cycles on the manufacturing process under the remelting process, as well as the internal mechanisms of microstructure evolution and performance improvement.

16

Grum, Janez, e Roman Šturm. "Residual Stress Profiles of the Laser Surface Remelted Nodular Irons". Materials Science Forum 490-491 (luglio 2005): 460–68. http://dx.doi.org/10.4028/www.scientific.net/msf.490-491.460.

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Laser remelting process is a very promising hardening method for ferrous and nonferrous alloys, which do not show a homogeneous microstructural state after having been heattreated in a traditional way. Consequently, the alloys concerned do not achieve the required hardness of the surface layer and do not provide the required wear resistance either. The paper deals with residual stresses of thin flat specimens of nodular cast iron 500-7 in the laser remelting process. In the process of gradual remelting of the specimen surface, that is during its heating and cooling, volume changes of the specimen occur due to thermal and microstructural changes. For a better knowledge of volume changes in the thin surface layer of the specimen, the latter were evaluated by residual-stress measurement in the thin modified surface layer after the remelting process. In laser remelting of a workpiece such remelting conditions should be ensured that a uniform thickness of the modified layer could be obtained in spite of several laser-beam passages across the workpiece surface. Because of a multiple laser-beam passage across the workpiece surface, the state of internal stress in the workpiece changes. Optimal laser surface remelting conditions on the basis of knowing the residual stresses were chosen, while the way of guiding the laser beam over the surface of flat samples and degree of overlapping were varied.

17

Hua, Yin Qun, Wen Wen Shuai, Wei Liu, Rui Fang Chen e Jiang Dong Cao. "The Study of High Temperature Oxidation Performance of Thermal Barrier Coatings Prepared by Plasma Spraying and Laser Remelting". Advanced Materials Research 1142 (gennaio 2017): 161–67. http://dx.doi.org/10.4028/www.scientific.net/amr.1142.161.

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The CoCrAlYTaSi/YSZ thermal barrier coating was prepared on the surface of GH586 by plasma spraying and laser remelting process. The coating prepared by plasma spraying, YSZ have no phase transformation. After remelting, YSZ also have no phase transformation, but the grain of the preferential growth orientation changed. Plasma spraying coating is mainly composed of t and t' phase, all the t phase transform into t' phase and recrystallization after remelting. After remelting, the substrate grain and γ' phase size are obviously grown up, leading to the decrease of high temperature oxidation resistance of substrate. In the process of oxidation, no obvious phase transformation are taken place in the plasma spraying coating, and the coating after laser remelting, tetragonal-monoclinic phase transformation happened.

18

Wang, Jia, De Hong Lu, Han Xiao, Rong Feng Zhou, Rong Zhou e Long Biao Wu. "Effect of Rolling-Remelting SIMA Process on Semi-Solid Microstructure of ZCuSn10 Alloy". Solid State Phenomena 217-218 (settembre 2014): 418–25. http://dx.doi.org/10.4028/www.scientific.net/ssp.217-218.418.

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Semi-solid billet of ZCuSn10 (Wt%: 88.25Cu, 10.48Sn) alloy is prepared by strain induced melt activated (SIMA) method which including rolling and remelting process. Firstly, ZCuSn10 alloy is casted, and rolling samples are cut from ingot casting. Secondly, the rolling samples are two pass or four pass rolled after holding 15 minutes at 450°C, then samples with 10% and 20% pre-deformation degree are obtained. The remelting samples are cut from pre-deformed samples. Lastly, the remelting samples are reheated up to 850°C or 875°C, water quenching after holding for 15 minutes. Then semi-solid microstructure of ZCuSn10 alloy is prepared. The semi-solid microstructure of ZCuSn10 alloy is observed and compared with annealed microstructure and microstructure of ZCuSn10 alloy directly remelted after casting. The results indicate that semi-solid microstructure of ZCuSn10 alloy by rolling-remelting SIMA process is uniform and fine grain, and spheroidization level of solid particle is well. The optimum semi-solid microstructure is obtained when alloy with pre-deformation 20% is remelted at 875°C for 15 minutes, the average grain diameter is about 75.80μm, shape factor is 1.62, and volume fraction of liquid phase reaches about 17.28%. Pre-deformation process plays a crucial role in grain refinement and spheroidization during SIMA process for preparing the semi-solid ZCuSn10 alloy, as pre-deformation degree and remelting temperature increases, volume fraction of liquid phase increases, the solid particles in semi-solid microstructure are smaller and rounder. The main mechanism of SIMA process preparing semi-solid billet of ZCuSn10 alloy is that pre-deformation breaks dendrites and stores energy of deformation into alloy, and promotes dendrites fusing through remelting process. Meanwhile, liquid phase occupies sharp corners of solid particles by Sn element diffusing from liquid phase into α solid phase, so that fine and uniform and globular α solid particles are gained.

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St Węglowski, M., P. Śliwiński, S. Dymek, I. Kalemba-Rec, M. Kapuściński, A. Wrona e K. Kustra. "A comprehensive study on the microstructure of plasma spraying coatings after electron beam remelting". Journal of Physics: Conference Series 2443, n. 1 (1 febbraio 2023): 012005. http://dx.doi.org/10.1088/1742-6596/2443/1/012005.

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Abstract One of the most popular thermal spraying technology is atmospheric plasma spraying (APS). However, it should be noted, that numerous imperfections in the APS surface layers can be occurred. The porosity, microcracks as well as lamellar microstructure occurred. Moreover, the adhesion of the coating is limited. However, the reduction of porosity and other imperfections by remelting process can be eliminated. The laser or electron beams for remelting are the most popular technologies. Mainly, power of the beam and travelling speed influence on the thickness and the final properties of the remelted coatings. In the paper, the electron beam (EB) process for remelting of plasma spraying surface layers in relation to microstructure is presented. The Ni20%Cr + 30%Re APS coating on stainless steel substrate 316Ti grade by electron beam was remelted. The effect of remelting process on microstructure was presented. The light microscopy (LM) as well as scanning electron microscopy (SEM) and energy disperse spectroscopy (EDS) for microstructure analysis of APS coatings after EB remelting were used. The results show that the APS coatings subjected EB remelted becomes much denser. Moreover, the porosity was reduced and the chemical composition of the coatings after remelting became homogeneous.

20

Dong, Yan Wu, Zhou Hua Jiang, Lian Ke Liang e Zheng Bang Li. "Behavior of Hydrogen during Electroslag Remelting Process". Materials Science Forum 675-677 (febbraio 2011): 843–46. http://dx.doi.org/10.4028/www.scientific.net/msf.675-677.843.

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Behavior of hydrogen in steel during electroslag remelting process was investigated on a laboratory-scale unit. Results indicated that a considerable amount of hydrogen was picked up by the metal at the beginning of the process. Hydrogen content decreased with the increasing of ingot height. To avoid the hydrogen peak, anhydrous components must be used. Protective atmosphere combining with premelted slag was the optimal measure to control hydrogen in steel when the solid-starting technique was carried out. According to the results in the experiment it was not the crucial factor for hydrogen in steel remelted under protective atmosphere whether slag contained lime or not at actual remelting period.

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Kasińska, Justyna, Dana Bolibruchová e Marek Matejka. "The Influence of Remelting on the Properties of AlSi9Cu3 Alloy with Higher Iron Content". Materials 13, n. 3 (25 gennaio 2020): 575. http://dx.doi.org/10.3390/ma13030575.

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This article aims to evaluate the influence of remelting on the experimental Al-Si-Cu type alloy with higher iron content on mechanical properties in relation to the resulting structure. The remelting or recycling process is one of the means of reducing the production costs of the forge plant. The experimental part deals with the analysis of the results of mechanical properties, structural analysis, and the process of crystallization of structural components and their changes due to the increased iron content caused by remelting at different states of the examined alloy. The effect of remelting and ageing on microstructure was observed using a combination of different analytical techniques (light microscopy, scanning electron microscopy (SEM), and upon deep etching and energy dispersive X-ray analysis (EDX)). Tensile strength and elongation tests point to the negative effect of alloying, a gradual increase in wt% Fe and a change in the morphology of the iron phases, which began to manifest significantly after the fourth remelting. The process of natural ageing has been shown to be effective only on alloys with a lower number of remelting cycles, whereas the application of artificial ageing has resulted in improved mechanical properties in all the test alloys.

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Ferng, Y. M., C. C. Chieng e Chin Pan. "NUMERICAL SIMULATIONS OF ELECTRO-SLAG REMELTING PROCESS". Numerical Heat Transfer, Part A: Applications 16, n. 4 (dicembre 1989): 429–49. http://dx.doi.org/10.1080/10407788908944725.

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Dong, Yan-wu, Zhou-hua Jiang e Zheng-bang Li. "Segregation of Niobium During Electroslag Remelting Process". Journal of Iron and Steel Research International 16, n. 1 (gennaio 2009): 7–11. http://dx.doi.org/10.1016/s1006-706x(09)60002-9.

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Jiang, Zhou-hua, Yan-wu Dong, Lian-ke Liang e Zheng-bang Li. "Hydrogen Pick-Up During Electroslag Remelting Process". Journal of Iron and Steel Research International 18, n. 4 (aprile 2011): 19–23. http://dx.doi.org/10.1016/s1006-706x(11)60044-7.

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Dai, Guangming, Lihua Zhan, Chenglong Guan e Minghui Huang. "Effect of forming process on mechanical and interfacial properties for thermoplastic composite I-stiffened structures". High Performance Polymers 34, n. 3 (9 dicembre 2021): 282–91. http://dx.doi.org/10.1177/09540083211051585.

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The forming process is the core factor to control the quality of thermoplastic composite components. In this paper, the common I-stiffened structures in the aerospace field were taken as the research object, and the forming process scheme was designed. Based on the prefabrication of C-shaped parts, the I-stiffened structures were prepared by the compression molding process. The influence law of molding temperature on the quality of the prefabricated C-shaped parts was explored. The time dependence of the PEEK melt viscosity was tested to provide the basis for the optimization of forming process parameters of I-stiffened structures. The influencing mechanism of thermoplastic composites repeatedly forming to the bonding strength of remelting interface was studied. The results show that repeated forming would lead to polymer aging and result in low bonding strength at the remelting interface of the I-stiffened structures. Optimizing the forming process could effectively reduce the aging of materials and improve the bonding strength of the remelting interface and overall mechanical properties of components. The research provides technical guidance for the manufacturing of complex thermoplastic composite components, especially the influence mechanism of the forming process on the bonding strength of remelting interface.

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Pourzamani, Hamidreza, Majid Falahati, Forouz Rastegari e Karim Ebrahim. "Freeze–melting process significantly decreases phthalate ester plasticizer levels in drinking water stored in polyethylene terephthalate (PET) bottles". Water Supply 17, n. 3 (15 ottobre 2016): 745–51. http://dx.doi.org/10.2166/ws.2016.172.

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Bottled water consumption has increased significantly in recent decades. Eighty percent of bottled water is sold in plastic containers usually made from polyethylene terephthalate (PET). Trace leaching of phthalate esters (PEs) from these bottles into the water and their effects on human health has become a serious concern. In this study, the effects of freezing on the release of PEs from PET bottles have been investigated. Four common PEs were determined in bottled water samples before and after freezing–remelting by a dispersive liquid–liquid micro-extraction method and gas chromatography–mass spectrometry (GC/MS) analysis. PE levels after freezing–remelting of samples were significantly lower than before (mean ± SD = 0.71 ± 0.28 and 0.33 ± 0.003 ppb, respectively). Electrical conductivity (EC) also decreased after freezing–remelting of the water (mean ± SD = 260.2 ± 80.6 and 130.6 ± 17.4 μs/cm, respectively). Significant correlation has been detected between reduction in water EC and elimination of PEs from water. Dissolved minerals and contaminants in water concentrate and conglomerate in the center of the ice during the freezing process and form white sediments mainly of calcium bicarbonate after remelting of the water. It seems that calcium bicarbonate effectively adsorbs PEs and traps them in its structures. These sediments do not have significant gastrointestinal absorption and cannot pose health consequences. The freezing–remelting process could be introduced as an effective procedure for water treatment.

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Weglowski, Marek Stanisław, Jerzy Dworak, Krzysztof Kwiecinski, Janusz Pikuła, Krzysztof Krasnowski, Robert Jachym, Stanisław Dymek, Izabela Kalemba-Rec, Adriana Wrona e Katarzyna Kustra. "Remelting of Thermal Spraying Coatings - Technologies, Properties and Applications". Materials Science Forum 1016 (gennaio 2021): 1597–602. http://dx.doi.org/10.4028/www.scientific.net/msf.1016.1597.

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The most popular spraying technologies include: flame spraying, arc spraying and plasma spraying. Spraying technologies allow for the formation of coatings with a desired chemical composition and thickness. However, such coatings characterize by numerous imperfections associated with the nature of the process itself. It is obvious that some of imperfections in thermal spraying coatings can be eliminated by choosing the right parameters of the process. However, in order to improve the properties and eliminate material discontinuous, it is necessary to conduct the remelting process. Research in most cases, showed that the reduction of porosity and simultaneous increase in hardness are possible only by remelting the coating using different heat sources. By adjusting the technological parameters and remelting speed, it is possible to precisely control the depth of the remelted material and thus the properties of final coatings. The paper presents the remelting processes of thermal spraying coatings in relation to technologies, properties and applications.

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Xie, Shi Kun, Rong Xi Yi, Xiu Yan Guo, Xiao Liang Pan e Xiao Qiu Zheng. "Remelting Technology and Microstructural Evolution of Semi-Solid Al-7Si-2RE Alloy". Applied Mechanics and Materials 33 (ottobre 2010): 1–5. http://dx.doi.org/10.4028/www.scientific.net/amm.33.1.

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In semi-solid remelting process, the various stages of reheating temperature and isothermal holding time must be accurately controlled in order to obtain the uniformly distributed and small equiaxed grains microstructure. In this paper, a temperature control program was developed and the remelting process for Al-7Si-2RE aluminum alloy was carried out. The results showed that with the raise of reheating temperature and the extension of isothermal holding time, the liquid fraction increases, α-phase grain grows and becomes rounding in the process of Al-7Si-2RE alloy semi-solid remelting. The most reasonable process parameter of reheating temperature is at 585~590°C and its appropriate isothermal holding time are about 10~15min for the semi-solid Al-7Si-2RE alloy.

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Li, Gang, Jing She Li, Shu Feng Yang, Yan Jie Wang e Nai Song Li. "Study on the Cleanliness of 316L Stainless Steel". Advanced Materials Research 311-313 (agosto 2011): 881–85. http://dx.doi.org/10.4028/www.scientific.net/amr.311-313.881.

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The process of three-phase electroslag furnacefoundry casting  electroslag remelting was used to produce 316L stainless steel ultra-fine wires with a diameter of 0.018mm. Breakage of the wire often occurs during drawing process due to the existence of inclusions in the steel. In order to improve the cleanliness of 316L steel, the deoxidizer and top slag composition were optimized by industrial trials in this production process. As a result, the total oxygen (T.O.) content decreased from 120 ppm to 57ppm. During the electroslag remelting process, the composition of electroslag and the power supply were optimized. Argon protection was used and electrode was washed by acid solution before refining. Finally, the T.O. in the remelting ingot can be controlled below 20 ppm.

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Anikeev, Andrey N., Ilia V. Chumanov e D. V. Sergeev. "Studying of Influence of Rotation of the Spent Electrode on the Microfirmness of the Received Preparation of Steel AISI 420 at Electroslag Remelting". Materials Science Forum 975 (gennaio 2020): 55–58. http://dx.doi.org/10.4028/www.scientific.net/msf.975.55.

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Data of skilled electroslag remelting of the spent brand AISI 420 steel electrodes on various technologies are provided (with rotation and without rotation of the spent electrode). Are noted, features of influence of rotation of the spent electrode on conditions of the course of process of remelting and crystallization of an ingot. Influence of a way of remelting on a complex of properties of the received ingot is analysed. The analysis of results of researches showed increase in uniformity of the studied properties at realization of technology of electroslag remelting with rotation of the spent electrode on the melting course.

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Burja, J., F. Tehovnik, M. Godec, J. Medved, B. Podgornik e R. Barbic. "Effect of electroslag remelting on the non-metallic inclusions in H11 tool steel". Journal of Mining and Metallurgy, Section B: Metallurgy 54, n. 1 (2018): 51–57. http://dx.doi.org/10.2298/jmmb160623053b.

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We have studied the effect of electroslag remelting on the content and composition of non-metallic inclusions. It was found that a decrease in the non-metallic inclusion content occurred during the electroslag remelting. A change in the chemical composition of the non-metallic inclusions was observed, while the aluminum and calcium contents were increased. The complexity of the inclusions also increased, as there were fewer single-phase inclusions after the electroslag remelting process. Based on the results and a thermodynamic assessment of the formation of the non-metallic inclusions, a mechanism for inclusion behavior during electroslag remelting has been proposed.

32

Chen, Shu Fa, Jian Bo Lei e Xiu Bo Liu. "Microstructure and Wear Resistance of Laser Remelted Boronizing Layer of Petrochemical Key Parts". Applied Mechanics and Materials 37-38 (novembre 2010): 658–61. http://dx.doi.org/10.4028/www.scientific.net/amm.37-38.658.

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The boronizing layers of 45 steel of drilling pump liner have been remelted with laser, and the wear resistance properties, phase transition and microstructures of the boronizing layers before and after laser remelting were analyzed. The results show that laser remelting enhances surface abrasive wear resistance properties by 40% ~90%. Laser remelting achieves improvements mostly by means of alternating boronizing layer morphologies, eliminating FeB and defects within boronizing layer, improving the interface bonding intensity, fining the microstructures, redistributing boron concentration and generating lots of alloy phases. The strong support to material surfaces by martensites gained during remelting process within transition area is also beneficial to improve wear resistance properties. It is shown from the practice that the laser remelting compound technology followed boronizing shall be widely used in surface hardening of petrochemical key parts.

33

Grum, J., e R. Šturm. "Optimisation of the laser surface remelting process on strain criteria". Journal de Physique IV 120 (dicembre 2004): 315–23. http://dx.doi.org/10.1051/jp4:2004120036.

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This paper shows a process of selection of optimum conditions for laser remelting of nodular cast iron. The optimisation takes into account a specified depth of the hardened layer, for which an appropriate energy input is specified while taking into account the mode of guiding the laser beam. Strain criteria are given for the optimisation of the remelting process, i.e., minimum energy input at a given depth of the hardened layer, minimum distortion of the machine part and a desired variation of residual stresses across the hardened layer. Practical tests of optimisation showed the logic of adhering to the aforementioned criteria, because we can significantly influence the quality of the product at lower costs of manufacturing.

34

Abdulwahab, Zaman A., Sami I. Jafar e Sami A. Ajeel. "Effect of Laser Process on Microstructure and Fatigue Resistance of Steam Turbine Blade". IOP Conference Series: Earth and Environmental Science 961, n. 1 (1 gennaio 2022): 012017. http://dx.doi.org/10.1088/1755-1315/961/1/012017.

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Abstract The steal turbine blades, operating in steam electricity production plants are subjected to periodic circular stresses that cause fatigue failure with the passage of time. The chemical composition so steam turbine blades show that is steel 52 it has a wide range of applications, mostly in welded construction, All kinds of welded construction, wind turbines, load-lifting equipment, platform components, cranes, bridge components, and structures. This research aims to study the microstructure of these turbine blades before and after the occurrence of fatigue, and for the purpose of improvement the fatigue resistance, the blades were treated with a laser and the amount of improvement in fatigue resistance was calculated and also the change in the microstructure after laser treatment was studied. The remelting process applied with this parameter Pulse energy = 8 joules, Pulse width = 4.5 Ms., Pulse frequency = 12 Hz, Laser Average Power = 96 W, Laser peak power = 1.78 KW. The results show, after remelting process the microstructure of the specimen is smooth and increase the cyclic of fatigue comparison with specimen without leaser remelting process. So, the fatigue resistance is increased.

35

Krajewski, Arkadiusz, e Paweł Kołodziejczak. "Analysis of the Impact of Acoustic Vibrations on the Laser Beam Remelting Process". Materials 15, n. 18 (15 settembre 2022): 6402. http://dx.doi.org/10.3390/ma15186402.

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The article contains an analysis of selected aspects of the structure and properties of laser remelting of low carbon steel supported by acoustic vibrations obtained in the research presented in (A Novel Method of Supporting the Laser Welding Process with Mechanical Acoustic Vibrations). Due to the assumptions made in this publication, it was necessary to deepen the analysis of the obtained results. The correlation of such factors on the structure as the frequency of vibrations (50, 100, 1385 Hz), their propagation through the short-lived liquid phase and changes in the structure, chemical composition, and hardness of the characteristic zones of the obtained remelting was considered. The remelting obtained with the participation of resonant acoustic vibrations with a frequency of 1385 Hz was subjected to thermo-mechanical analysis. A characteristic “bandwidth” pattern was revealed in the structure. In the present article, a thermo-mechanical analysis of the cause of its formation was carried out by comparing it with the remelting obtained at lower frequencies. As a result of the analysis, it was found that the band structure was characterized by 7 to 8 areas up to approximately a 90 µm depth, which showed dark and light zones. These areas differed in carbon content, hardness, and width. The analysis of vibration propagation helped to determine that in the time of crystallization of the molten metal pool, the transition of the vibration wave lasted through 7–8 minima and maxima. This fact allows us to assume with a high probability that it is the result of the applied resonance frequency.

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Yang, Zhiyuan, Chan Guo, Tao Sun, Jinpeng Hu, Xiaomei Feng e Yifu Shen. "The Effect of Laser Remelting during SLM on Microstructure and Mechanical Properties of CoCrFeNiNb0.25". Materials 17, n. 9 (27 aprile 2024): 2061. http://dx.doi.org/10.3390/ma17092061.

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A sub-eutectic high-entropy alloy composed of CoCrFeNiNb0.25 was prepared using a combination of mechanical powder mixing and selective laser melting (SLM). The mechanical properties of the alloy were enhanced by employing an interlayer laser remelting process. This study demonstrates the feasibility of using mechanical mixing and SLM to form an CoCrFeNiNb0.25 alloy. The interlayer laser remelting process can effectively promote the melting of Nb particles introduced by mechanical mixing, release the stresses near the unfused Nb particles, and reduce their degradation of the specimen properties. The results indicate that the CoCrFeNiNb0.25 alloy, prepared using the interlayer laser remelting process, had an average microhardness of 376 HV, a tensile strength of 974 MPa, and an elongation at break of 10.51%. This process offers a viable approach for rapidly adjusting the composition of high-entropy alloys for SLM forming.

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Tong, Wenjie, Wanming Li, Ximin Zang, Huabing Li, Zhouhua Jiang e Dejun Li. "A Comprehensive Mathematical Model of Electroslag Remelting with Two Series-Connected Electrodes Based on Sequential Coupling Simulation Method". Metals 10, n. 5 (19 maggio 2020): 658. http://dx.doi.org/10.3390/met10050658.

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A comprehensive mathematical model of electroslag remelting with two series-connected electrodes (TSCE-ESR) was constructed based on sequential coupling method. The influence of droplet effect on electroslag remelting process (ESR) was considered in this model. Compared with one-electrode electroslag remelting (OE-ESR), the multi-physics field, droplet formation and dripping behavior, and molten metal pool structure of TSCE-ESR process were studied. The results show that during the process of TSCE-ESR, the proximity effect of the electrodes suppresses the skin effect, and Joule heat is concentrated in the area between the two electrodes of slag pool, making the temperature distribution of the slag pool more uniform. The heat used to melt the electrode in the process of TSCE-ESR accounts for about 34% of the total Joule heat, which is lower than the OE-ESR (17%). Therefore, it makes a higher melting rate and a smaller droplet size in the process of TSCE-ESR. Compared with OE-ESR, TSCE-ESR process can realize the unification of higher melting rate and shallow flat molten metal pool. Compared with the results without droplet effect, it is found that in the simulation results with droplet effect, the depth and the cylindrical section of molten metal pool increased, and the width of the mushy zone is significantly reduced, which is more consistent with the actual electroslag remelting process.

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Mohammed, M. N., M. Z. Omar, M. S. Salleh e K. S. Alhawari. "Study on Thixojoining Process Using Partial Remelting Method". Advances in Materials Science and Engineering 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/251472.

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Cold-work tool steel is considered to be a nonweldable metal due to its high percentage content of carbon and alloy elements. The application of a new process of the semisolid joining of two dissimilar metals is proposed. AISI D2 cold-work tool steel was thixojoined to 304 stainless steel by using a partial remelting method. After thixojoining, microstructural examination including metallographic analysis, energy dispersive spectroscopy (EDS), and Vickers hardness tests was performed. From the results, metallographic analyses along the joint interface between semisolid AISI D2 and stainless steel showed a smooth transition from one to another and neither oxides nor microcracking was observed. Hardness values obtained from the points in the diffusion zone were much higher than those in the 304 stainless steel but lower than those in the AISI D2 tool steel. The study revealed that a new type of nonequilibrium diffusion interfacial structure was constructed at the interface of the two different types of steel. The current work successfully confirmed that avoidance of a dendritic microstructure in the semisolid joined zone and high bonding quality components can be achieved without the need for force or complex equipment when compared to conventional welding processes.

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Castillo, B., e Ja Alvarez. "Nonlinear Adaptive Control of an Electroslag Remelting Process". IFAC Proceedings Volumes 22, n. 11 (settembre 1989): 221–25. http://dx.doi.org/10.1016/s1474-6670(17)53113-4.

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Jardy, A. "Mathematical modelling of the vacuum arc remelting process". Revue de Métallurgie 100, n. 6 (giugno 2003): 595–605. http://dx.doi.org/10.1051/metal:2003122.

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41

Kang, B., J. Waldvogel e D. Poulikakos. "Remelting phenomena in the process of splat solidification". Journal of Materials Science 30, n. 19 (ottobre 1995): 4912–25. http://dx.doi.org/10.1007/bf01154504.

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42

Amon, C. H., K. S. Schmaltz, R. Merz e F. B. Prinz. "Numerical and Experimental Investigation of Interface Bonding Via Substrate Remelting of an Impinging Molten Metal Droplet". Journal of Heat Transfer 118, n. 1 (1 febbraio 1996): 164–72. http://dx.doi.org/10.1115/1.2824030.

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A molten metal droplet landing and bonding to a solid substrate is investigated with combined analytical, numerical, and experimental techniques. This research supports a novel, thermal spray shape deposition process, referred to as microcasting, capable of rapidly manufacturing near netshape, steel objects. Metallurgical bonding between the impacting droplet and the previous deposition layer improves the strength and material property continuity between the layers, producing high-quality metal objects. A thorough understanding of the interface heat transfer process is needed to optimize the microcast object properties by minimizing the impacting droplet temperature necessary for superficial substrate remelting, while controlling substrate and deposit material cooling rates, remelt depths, and residual thermal stresses. A mixed Lagrangian–Eulerian numerical model is developed to calculate substrate remelting and temperature histories for investigating the required deposition temperatures and the effect of operating conditions on remelting. Experimental and analytical approaches are used to determine initial conditions for the numerical simulations, to verify the numerical accuracy, and to identify the resultant microstructures. Numerical results indicate that droplet to substrate conduction is the dominant heat transfer mode during remelting and solidification. Furthermore, a highly time-dependent heat transfer coefficient at the droplet/substrate interface necessitates a combined numerical model of the droplet and substrate for accurate predictions of the substrate remelting. The remelting depth and cooling rate numerical results are also verified by optical metallography, and compare well with both the analytical solution for the initial deposition period and the temperature measurements during droplet solidification.

43

Chen, Qiang, Gao Zhan Zhao e Da Yu Shu. "Study on Microstructural Evolution of Deformed Magnesium Alloy during Partial Remelting". Solid State Phenomena 192-193 (ottobre 2012): 246–50. http://dx.doi.org/10.4028/www.scientific.net/ssp.192-193.246.

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Microstructural evolution of ZK60 Mg alloy during partial remelting was investigated in this paper. The results show that ZK60 Mg alloy semi-solid billets were successfully produced by recrystallisation and partial remelting (RAP) process. Following partial remelting in each case, grain coarsening had occurred in the semi-solid state with increasing holding time. Liquid was present, during partial remelting all four temperatures, in the form of isolated intragranular droplets. These liquid droplets were produced by intragranular eutectic phase and entrapped liquid. Intragranular liquid droplets migrated and merged into some large rounded liquid droplets. After the spheroidization was completed, coarsening and coalescence occurred. When temperature is relatively low (the thickness of liquid is relatively thin), grains contacted with each other, which produced irregular-shaped grains.

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Campbell, John. "A Future for Vacuum Arc Remelting and Electroslag Remelting—A Critical Perspective". Metals 13, n. 10 (23 settembre 2023): 1634. http://dx.doi.org/10.3390/met13101634.

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In the secondary metals refining processes, vacuum arc remelting (VAR) and electroslag remelting (ESR), the consumable electrode is commonly produced by vacuum induction melting (VIM) which employs the regrettably primitive casting technique of simply pouring into the open top of the mold. Despite the vacuum, the resulting oxidizing conditions and the immensely powerful turbulence accompanying the top-pouring of the electrode is now known to create a substantial density of serious cracks. The cracks in the cast electrode are bifilms (double oxide films), which in turn are proposed to be responsible for the major faults of the VAR ingot, including undetectable, horizontal macroscopic cracks, white spots (clean and dirty varieties) and in-fallen crown. The remedial action to solve all these issues at a stroke is the provision of a counter-gravity cast electrode, cast in air or vacuum, or provision of any similar electrode substantially free from bifilm defects. The ESR process is also described, explaining the reasons for its significantly reduced sensitivity to the top-poured VIM electrode, but indicating that with an improved electrode, this already nearly reliable process has the potential for perfect reliability. The target of this critical overview is an assessment of the potential of these secondary refining processes to produce, for the first time, effectively defect-free metals, metals we can trust.

45

Rao, Lei, Qi Yao Hu e Xiao Long Li. "Numerical Simulation Study of Consumable Electrode Melting Process in Electro-Slag Remelting Ingots". Advanced Materials Research 189-193 (febbraio 2011): 3895–98. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.3895.

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Electro-slag remelting (ESR) is a kind of special metallurgy techniques to produce high quality alloy materials. The interface of electrode and slag is the energy entrance of entire system in the remelting process. Mathematical model of consumable electrode’s melting process has been built in this paper. Some valuable variation rules of droplet diameter, droplet forming time, melting rate and purification coefficient following melting current and slag bath depth have been studied through a series of simulation work. Based on the mechanism studying of the consumable electrode’s melting, some meaningful experience to optimize the technological parameters and improve material quality of electro slag ingot has been gotten.

46

Uţu, Ion Dragoş, Gabriela Marginean, Iosif Hulka e Viorel Aurel Şerban. "Sliding Wear Behavior of Remelted Al₂O₃-TiO₂ Plasma Sprayed Coatings on Titanium". Solid State Phenomena 254 (agosto 2016): 231–36. http://dx.doi.org/10.4028/www.scientific.net/ssp.254.231.

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Microstructure and wear properties of the Al2O3-13.wt% TiO2 thermally sprayed coatings before and after remelting were investigated in this study. The coatings were deposited on a pure titanium substrate using the atmospheric plasma spraying (APS) process. The as-sprayed coatings were electron beam (EB) modified in order to improve their compactness and bonding strength.The effect of EB remelting on the microstructure, phase constituents and wear properties was investigated using scanning electron microscopy (SEM), X-Ray diffraction technique and hardness measurements. The sliding wear behavior was tested using a pin on disk method.The results showed that the remelting process had a positive effect removing the lamellar defect of the as-sprayed coating and improving the compactness, hardness and wear behavior.

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Hu, Kang Kai, Shi Cheng Wang, Wei Gao, Hong Ying Yu e Dong Bai Sun. "Microstructure Evolution and Performance of Laser-Remelted Ti-6Al-4V Alloy". Materials Science Forum 1071 (18 ottobre 2022): 46–55. http://dx.doi.org/10.4028/p-ipjl43.

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Herein, Ti-6Al-4V alloy was remelting by high-energy laser, the influence of laser energy density of mobile laser source on the evolution of solidification structure of Ti-6Al-4V alloy was studied, and the changes of relevant service performance of Ti-6Al-4V alloy after laser-remelting were explored. The results showed that there were four distinct regions: overheated zone, melting zone, heat-affected zone and substrate zone in Ti-6Al-4V alloy after laser remelting. The overheated zone and melting zone were dominated by primary α phase and secondary α phase, and a heat-affected zone was dominated by β phase. With the increase of laser energy density, the depth of molten pool and the range of melting zone in Ti-6Al-4V alloy increased, and the crystal phase distribution and grain size changed significantly. Laser-remelting Ti-6Al-4V alloy could still maintain a good passive state in the potentiodynamic polarization curve test, and the optimal laser power during remelting was 1200 W. This study proved that the crystal phase composition and grain size during the solidification process after laser-remelting were a key factor affecting the service performance of Ti-6Al-4V alloy.

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Iwaszko, J., e M. Strzelecka. "Structural Aspects of Remelting of the AZ91 Magnesium Alloy Surface Layer". Archives of Foundry Engineering 16, n. 1 (1 marzo 2016): 13–18. http://dx.doi.org/10.1515/afe-2015-0095.

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Abstract In this study, modification of the AZ91 magnesium alloy surface layer with a CO2 continuous wave operation laser has been taken on. The extent and character of structural changes generated in the surface layer of the material was being assessed on the basis of both macro- and microscopy investigations, and the EDX analysis. Considerable changes in the structure of the AZ91 alloy surface layer and the morphology of phases have been found. The remelting processing was accompanied by a strong refinement of the structure and a more uniform distribution of individual phases. The conducted investigations showed that the remelting zone dimensions are a result of the process parameters, and that they can be controlled by an appropriate combination of basic remelting parameters, i.e. the laser power, the distance from the sample surface, and the scanning rate. The investigations and the obtained results revealed the possibility of an effective modification of the AZ91 magnesium alloy surface layer in the process of remelting carried out with a CO2 laser beam.

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Okugawa, Masayuki, Yuya Furushiro e Yuichiro Koizumi. "Effect of Rapid Heating and Cooling Conditions on Microstructure Formation in Powder Bed Fusion of Al-Si Hypoeutectic Alloy: A Phase-Field Study". Materials 15, n. 17 (2 settembre 2022): 6092. http://dx.doi.org/10.3390/ma15176092.

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Al alloy parts fabricated by powder bed fusion (PBF) have attracted much attention because of the degrees of freedom in both shapes and mechanical properties. We previously reported that the Si regions in Al-Si alloy that remain after the rapid remelting process in PBF act as intrinsic heterogeneous nucleation sites during the subsequent resolidification. This suggests that the Si particles are crucial for a novel grain refinement strategy. To provide guidelines for grain refinement, the effects of solidification, remelting, and resolidification conditions on microstructures were investigated by multiphase-field simulation. We revealed that the resolidification microstructure is determined by the size and number of Si regions in the initial solidification microstructures and by the threshold size for the nucleation site, depending on the remelting and resolidification conditions. Furthermore, the most refined microstructure with the average grain size of 4.8 µm is predicted to be formed under conditions with a large temperature gradient of Gsol = 106 K/m in the initial solidification, a high heating rate of HR = 105 K/s in the remelting process, and a fast solidification rate of Rresol = 10−1 m/s in the resolidification process. Each of these conditions is necessary to be considered to control the microstructures of Al-Si alloys fabricated via PBF.

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Xia, Ming-Xu, Hong-xing Zheng, Sen Yuan e Jian Guo Li. "Phase and Morphological Transformation of Preformed AZ91D Magnesium Alloys in Remelting". Materials Science Forum 475-479 (gennaio 2005): 473–76. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.473.

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The phase and morphological transformation during the remelting process was investigated by isothermal soaking and rapidly quenching of preformed AZ91D magnesium alloys in semisolid state. It was revealed that the morphological transformation of preformed alloys is crucial to obtain homogenously fine spheroidal grains and affect the final forming ability. The transformation is divided into two stages, local remelting of the whole experiment and partial remelting of the respective grains, which behave as liquid bands and liquid cells structures, respectively. In the partial melting, the lower melting point phase, β-Mg17Al12, diffused to the grains boundary and center of the grains and separated to Al2Mg and Mg. The Al2Mg and Mg phases with lower melting points melt into cells structures. The final microstructure of the remelting experiments is composed of cells structures, spheroidal grains and liquid phase.

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