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1
Ravi, R. "Metallurgy of Basic Weld Metal". Indian Welding Journal 32, nr 3 (1.07.1999): 51. http://dx.doi.org/10.22486/iwj.v32i3.177678.
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Sundaresan, S. "Metallurgy of Welding Stainless Steels". Advanced Materials Research 794 (wrzesień 2013): 274–88. http://dx.doi.org/10.4028/www.scientific.net/amr.794.274.
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Based primarily on microstructure, five stainless steel types are recognized: ferritic, martensitic, austenitic, duplex and precipitation-hardening. The major problem in ferritic stainless steels is the tendency to embrittlement, aggravated by various causes. During welding, control of heat input is essential and, in some cases, also a postweld heat treatment. The austenitic type is the easiest to weld, but two important issues are involved in the welding of these steels: hot cracking and formation of chromium carbide and other secondary phases on thermal exposure. The nature of the problems and remedial measures are discussed from a metallurgical perspective. Duplex stainless steels contain approximately equal proportions of austenite and ferrite. The article discusses the upset in phase balance during welding both in the weld metal and heat-affected zone and the formation of embrittling secondary phases during any thermal treatment. Martensitic stainless steels are susceptible to hydrogen-induced cracking. Welding thus involves many precautions to prevent it through proper preheat selection, postweld heat treatment, etc. In the welding of precipitation-hardening stainless steels, it is usually necessary to develop in the weld metal strength levels matching those of the base metal. This is achieved by applying a postweld heat treatment appropriate to each type of alloy.
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Dahmen, Martin, Stefan Lindner, Damien Monfort i Dirk Petring. "Weld Metallurgy and Mechanical Properties of High Manganese Ultra-high Strength Steel Dissimilar Welds". Physics Procedia 83 (2016): 344–51. http://dx.doi.org/10.1016/j.phpro.2016.08.036.
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Coetsee, Theresa, i Frederik De Bruin. "A Review of the Thermochemical Behaviour of Fluxes in Submerged Arc Welding: Modelling of Gas Phase Reactions". Processes 11, nr 3 (22.02.2023): 658. http://dx.doi.org/10.3390/pr11030658.
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This review is focused on the thermochemical behaviour of fluxes in submerged arc welding (SAW). The English-language literature from the 1970s onwards is reviewed. It was recognised early on that the thermochemical behaviour of fluxes sets the weld metal total ppm O and the element transfer extent from the molten flux (slag) to the weld pool. Despite the establishment of this link between the flux-induced oxygen potential and element transfer, it is also well accepted that the slag–metal equilibrium does not control SAW process metallurgy. Instead, the gas phase must be taken into account to better describe SAW process metallurgy equilibrium calculations. This is illustrated in the gas–slag–metal equilibrium simulation model developed by Coetsee. This model provides improved accuracy in predicting the weld metal total ppm O values as compared to the empirical trend of Tuliani et al. Recent works on the application of Al metal powder with alloying metal powders provide new insights into the likely gas phase reactions in the SAW process and the modification of the flux oxygen behaviour via Al additions. Aluminium may lower the partial oxygen pressure in the arc cavity, and aluminium also lowers the partial oxygen pressure at the weld pool–slag interface. The weld metal total ppm O is lowered with the addition of aluminium in SAW, but not to the same extent as would be expected from steelmaking ladle metallurgy de-oxidation practice when using Al as de-oxidiser. This difference indicates that slag–metal equilibrium is not maintained in the SAW process.
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Butkovic, Samir, i Emir Saric. "EXPERIMENTAL INVESTIGATION OF WELD JOINTS BETWEEN SINTERED NB MODIFIED HK30 STAINLESS STEEL AND WROUGHT/CAST STAINLESS STEELS". International Journal of Advanced Research 9, nr 11 (30.11.2021): 80–84. http://dx.doi.org/10.21474/ijar01/13715.
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Very important property of powder metallurgy parts is ability to join to components produced by different manufacturing technologies or dissimilar materials. Properties of powder metallurgy Nb modified HK30 components are highly influenced by conditions applied during sintering. Weldability of sintered components can be improved using favorable sintering conditions. In this regard, effect of sintering parameters on fusion weldability of Nb modified HK30 is presented in this paper. Investigation of weld joints between HK30, produced by different sintering conditions, and cast HK30 stainless steel is performed. In addition, examination of welds between sintered HK30 and wrought 304 stainless steel is also performed. Microstructural examination and hardness testing of fusion zones and heat affected zones were done for different combinations of base material.
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Schwarz, Ladislav, Tatiana Vrtochová i Koloman Ulrich. "Electron Beam Welding of Duplex Steels with using Heat Treatment". Research Papers Faculty of Materials Science and Technology Slovak University of Technology 18, nr 28 (1.01.2010): 75–80. http://dx.doi.org/10.2478/v10186-010-0009-z.
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Electron Beam Welding of Duplex Steels with using Heat Treatment This contribution presents characteristics, metallurgy and weldability of duplex steels with using concentrated energy source. The first part of the article describes metallurgy of duplex steels and the influence of nitrogen on their solidification. The second part focuses on weldability of duplex steels with using electron beam aimed on acceptable structure and corrosion resistance performed by multiple runs of defocused beam over the penetration weld.
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Liang, Wei, Ruming Geng, Jianguo Zhi, Jing Li i Fei Huang. "Oxide Metallurgy Technology in High Strength Steel: A Review". Materials 15, nr 4 (11.02.2022): 1350. http://dx.doi.org/10.3390/ma15041350.
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Oxide metallurgy technology plays an important role in inclusion control and is also applied to improve the weldability of high strength steel. Based on the requirements of the weldability in high strength steel, the influencing factors of weld heat affected zone (HAZ) as well as the development and application status of oxide metallurgy technology are summarized in this review. Moreover, the advantages and difficulties in the application of rare earth (RE) oxide metallurgy technology are analyzed, combined with the performance mechanism of RE and its formation characteristics of fine and high melting point RE inclusions with distribution dispersed in liquid steel. With the weldability diversities of different high strength steels, the research status of weldability of high strength steel with high carbon equivalent and the effects of RE on the microstructure and properties of HAZ are discussed, and some suggestions about further research in the future are proposed.
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Che Lah, Nur Azida, Azman Jalar i Norinsan Kamil Othman. "Post-Weld Oxidation Behavior of AA6061 Al Alloy". Advanced Materials Research 399-401 (listopad 2011): 2087–90. http://dx.doi.org/10.4028/www.scientific.net/amr.399-401.2087.
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Welded AA6061 Al alloy using ER5356 (Al-5Mg) filler was oxidized in flowing air gas for 40hrs at 600oC at a total pressure of approximately 1 atm. The morphology and microstructure of welded joint after exposure was characterized by using optical metallurgy microscopy and Scanning Electron Microscope (SEM). Different oxide morphologies and textures were observed on parent and fusion metal due to the differences of the alloying element. The oxidation mechanism represented a complex reaction occur where the morphology and phase formation of the oxide shows the protective oxide scales showed the protective oxide were developed on parent metal side, meanwhile non-protective oxide scale formed on fusion metal of the welded Al alloy. It can be concluded that the welded area failed to resist oxidation behavior compared to the parent metal. The differ results are discuss in term of microstructure changes caused by high temperature oxidation exposure and alloying element.
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Bayley, C. J., i A. Mantei. "Influence of Weld Heat Input on the Fracture and Metallurgy of HSLA-65". Canadian Metallurgical Quarterly 48, nr 3 (wrzesień 2009): 311–16. http://dx.doi.org/10.1179/cmq.2009.48.3.311.
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Viňáš, Ján, Miroslav Greš i Tomáš Vaško. "Cladding of Wear-Resistant Layers in Metallurgy and Engineering". Materials Science Forum 862 (sierpień 2016): 41–48. http://dx.doi.org/10.4028/www.scientific.net/msf.862.41.
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The paper presents the application of weld layers used in renovations of functional surfaces of components that are exposed to several tribodegradation factors in operation of metallurgical and engineering industries. Surfaces of selected components are renovated using arc welding processes, namely: (MMAW) Manual Metal Arc Welding, (SAW) Submerged Arc Welding methods, (GMAW) Gas metal arc welding and (FCAW) Flux cored wire metal arc welding without gas shield. Claddings were made always three-layered directly on the surfaces of renovated components using dedicated cladding machines in operations and laboratory conditions respectively. Their quality was assessed using non-destructive tests, namely (VT) visual testing by STN EN ISO 17637 and (UT) Ultrasonic testing STN EN ISO 11666. Within the destructive tests the quality of claddings was evaluated using the metallographic analysis conducted on a light microscope Olympus BX and electron microscope Jeol where the impact of mixing the weld metal as well as heat treatment after cladding on the final structure of claddings was observed. Using the Shimadzu HMV 2 device the microhardness of cladding layers was evaluated on metallographic samples by STN EN ISO 9015-2. In laboratory conditions the resistance of cladding layers to abrasive wear was verified on the device Di-1. Experimental testing of the claddings confirmed that the selected additives and cladding parameters witting individual technology were chosen correctly as in cladding layers no presence of internal defects was observed.
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Krivonosova, Ekaterina A., Ekaterina K. Krivonosova i Dmitriy Trushnikov. "Fractal Geometry in Metallurgy of Welding and Coatings". Materials Science Forum 893 (marzec 2017): 252–56. http://dx.doi.org/10.4028/www.scientific.net/msf.893.252.
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Application of new methods for the description of structure of metals and alloys, the identification of new quantitative structure-morphology tours are especially important to establish the relationship "structure - property" and predicting the properties of weld metal on the basis of mathematical modeling. In our work we applied a fractal approach to the analysis of following objects: structure of metal during welding, fatigue fracture surface of metal of welded joints, structure of coatings in microarc oxidation, macrostructure of the heat-resistant steels during electron beam welding
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Matarneh, Mohammad E., Nabeel S. Gharaibeh, Valeriy V. Chigarev i Havrysh Pavlo Anatoliiovych. "Reduction of Copper to Steel Weld Ductility for Parts in Metallurgical Equipment". Journal of Mechanical Engineering 17, nr 1 (1.04.2020): 103–14. http://dx.doi.org/10.24191/jmeche.v17i1.15222.
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Despite being challenging, the welding of the dissimilar metals copper and steel is an essential process that is required for improving quality of equipment manufacturing in the fields of metallurgy, machine construction, and chemical industry. Restricted solubility of iron in copper leads to the formation of a supersaturated solid solution of iron and other chemical elements in the weld pool. Investigations have found the possibility of enhancing the process of welding copper with steel. In the case of using a flux-cored welding wire and an improved welding technique, the number of dendritic inclusions is reduced, and the weld ductility is improved. Studying the microstructure of a copper to steel weld confirmed the ability to enhance the outcome of the welding process of the dissimilar metals. The implementation of recommended preparation techniques of parts before welding, and optimization of the welding technique will increase the strength of the welds and, increases the operational reliability of metallurgical equipment.
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Yermolenko, D. Yu, V. V. Holovko i S. M. Stepanuyk. "Cellular automata for simulation of dendritic growth with surface active refractory inoculants". Journal of Achievements in Materials and Manufacturing Engineering 2, nr 88 (1.06.2018): 49–54. http://dx.doi.org/10.5604/01.3001.0012.6151.
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Purpose: During weld metal structure formation the possibility of impact on its mechanical properties are much more limited in comparison with metallurgy and technology of steel production. Adding of the inoculants to the welding pool is one of the promising methods of influencing the structure and mechanical properties of the weld metal. Design/methodology/approach: Cellular automata (CA) with additions of finite difference method (FDM) is one of the best ways to simulate dendritic growth process with the surfaceactive inoculants. It`s easy to add new rules of interaction between the inoculants and dendrite surface to the cellular automata model. Findings: It was found that average distance between primary dendrites axis decrease with increase of the inoculants wetting angle by melt iron. Obtained results were confirmed experimentally on weld metal samples that were obtained by the welding of HSLA steels with the surface-active inoculants. Research limitations/implications: The inoculants with size that comparable with cells size of the model (!0.4 microns) were distributed evenly in computational area. Practical implications: Adding of surface-active inoculants to the melt metal improve structure and mechanical properties of weld metal. Different refractory particles (TiC, TiN, SiC, TiO2, Al2O3 and ZrO2) can be used. Originality/value: Refractory inoculants adding to the melt metal are wide used in metallurgy as crystallization centers and heat absorbers. Inoculants that were added to the welding pool of high-strength low-alloyed (HSLA) steel welds could also influence on crystallization processes of weld metal as surface active particles. In the contact point between the dendrite surface and the surface-active inoculant, a surface energy is change depending of the inoculant surface properties. Different refractory particles (TiC, TiN, SiC, TiO2, Al2O3 and ZrO2) were used.
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Shah, N. K. "Report on Welding Metallurgy of Girth Weld Defects in Mechanised GMA Field-Welded Pipe Lines". Indian Welding Journal 26, nr 2 (1.04.1993): 1. http://dx.doi.org/10.22486/iwj.v26i2.148269.
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Han, Xiufeng, Guoliang Zhu, Qingbiao Tan i Baode Sun. "Effect of Semi-Aging Heat Treatment on Microstructure and Mechanical Properties of an Inertia Friction Welded Joint of FGH96 Powder Metallurgy Superalloy". Metals 13, nr 3 (22.03.2023): 632. http://dx.doi.org/10.3390/met13030632.
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Inertia friction welded joints often present different microstructures than the base metal, and subsequent heat treatment processes are always needed to maintain superior performance. This study investigates the effect of semi-aging heat treatment after welding on the microstructure, residual stress, micro-hardness, and tensile properties of inertia friction welded FGH96 powder metallurgy superalloy using optical microscopy, scanning electron microscopy, X-ray diffraction, and hardness and tensile tests. The results show that the semi-aging heat treatment after welding does not affect the grain size or grain morphology of the base metal. However, the recrystallization process can be further promoted in the weld nugget zone and transition zone. Meanwhile, the grain size is refined and the residual stress is significantly reduced in the welded joint after the same heat treatment. Under the synergetic strengthening effect of the γ′ phase, semi-aging heat treatment increased the micro-hardness of the weld nugget zone from 470 HV to 530 HV and improved the average tensile strength at room temperature by 118 MPa. These findings provide a reference for the selection of the heat treatment process after inertia friction welding of nickel-based powder metallurgy superalloys.
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Lemecha, Magdalena, Jerzy Napiórkowski, Krzysztof Ligier, Wojciech Tarasiuk i Krzysztof Sztukowski. "Analysis of Wear Properties of Powder Metallurgy Steel in Abrasive Soil Mass". Materials 15, nr 19 (4.10.2022): 6888. http://dx.doi.org/10.3390/ma15196888.
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This study presents the results of testing for abrasive wear of Vanadis 60 SuperClean powder metallurgy steel as compared to Hardox 600 steel and PMFe60P padding weld. The testing was conducted by the “rotating bowl” method using natural abrasive soil masses. Two types of abrasive masses with particle size distributions corresponding to light soil and medium soil were used. The obtained results enable the conclusion that the weight loss for Vanadis 60 SuperClean powder steel in both types of abrasive mass was approximately seven times lower than that for Hardox 600 steel and two times lower than PMFe60P padding weld. The high resistance of powder steel to abrasive wear in abrasive soil masses is related to the presence of a large number of fine M6C (tungsten-molybdenum) and MC (vanadium) carbide precipitates in its microstructure. The obtained test results indicate that the application of Vanadis 60 SuperClean steel may be extended to working elements operating in mineral abrasive environments.
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Manitsas, Dimosthenis, i Joel Andersson. "Hot Cracking Mechanisms in Welding Metallurgy: A Review of Theoretical Approaches". MATEC Web of Conferences 188 (2018): 03018. http://dx.doi.org/10.1051/matecconf/201818803018.
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Hot cracking often refers to the appearance of liquid films along grain boundaries or to another place in the weld metal structure. Despite hot cracking importance in alloy weldability, there is limited understanding of the influencing mechanisms. Theories and criteria worked out over the years to assess alloy weldability will be presented. The review focuses on: 1) Theories of hot cracking, 2) Hot cracking criteria, and 3) A criticism of hot cracking theories and criteria.
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Treutler, K., S. Brechelt, H. Wiche i V. Wesling. "Beneficial use of hyperbaric process conditions for welding of aluminium and copper alloys". Welding in the World 65, nr 8 (27.02.2021): 1623–31. http://dx.doi.org/10.1007/s40194-021-01088-1.
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AbstractThe joining of components with as few weld layers as possible is an important aspect of weld seam design due to the resulting reduced manufacturing effort and reduced influence of thermal cycles on the base material as well as reduced distortion. For materials with good thermal conductivity, this is not easily possible. The energy density of the arc has been found to be the core parameter for determining the penetration. In the present work, it is shown how the use of a hyperbaric process environment (2 to 16 bar) allows an increase of the energy density of the arc and thus an increase of the penetration depth for selected aluminium and copper alloys. Furthermore, the effects of this novel approach on weld metal metallurgy are presented. It is shown that the penetration depth can be doubled by increasing the ambient pressure. Furthermore, a statistical model for the prediction of the penetration depth depending on the welding parameters will be presented.
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Yang, Lu, Qing Hua Wang, Jie Li, Yuan Liu i An Guo Huang. "Reaction Kinetics of Mg2Si in the Laser Welding Pool of Aluminum Alloys". Advanced Materials Research 813 (wrzesień 2013): 55–63. http://dx.doi.org/10.4028/www.scientific.net/amr.813.55.
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The metallurgy reactions in the weld pool were analyzed with the application of reaction kinetics. Furthermore a formula to quantificationally calculate the amount of Mg2Si was generated. By means of calculating the thermodynamic condition of the reaction and combined with the verification testing, this article indicates that the metallurgical product Mg2Si was created in the liquid weld pool but not separated out from the arborescent crystal during its solid state. This thesis summarizes the precipitation mechanism of Mg2Si and explains the configuration, amount and location where Mg2Si was separated out by analyzing the phase diagrams and constitution diagrams. Relevant data suggests that: the content of Mg2Si is slightly less than Mg.
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Muth, T. R., Y. Yamamoto, D. A. Frederick, C. I. Contescu, W. Chen, Y. C. Lim, W. H. Peter i Z. Feng. "Causal Factors of Weld Porosity in Gas Tungsten Arc Welding of Powder-Metallurgy-Produced Titanium Alloys". JOM 65, nr 5 (16.03.2013): 643–51. http://dx.doi.org/10.1007/s11837-013-0592-5.
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Lyuty, O. "Metallurgical school of the Kyiv polytechnic institute and sources of electroslag remelting". History of science and technology 6, nr 8 (22.06.2016): 17–27. http://dx.doi.org/10.32703/2415-7422-2016-6-8-17-27.
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Metallurgical researches began at the Kyiv Polytechnic Institute in the first years of foundation. In 1935 Ye.O. Paton was founded department in the Electric Welding Institute and the Department of welding technology production in the KPI. A graduate of the Metallurgy Faculty of KPI V.I. Dyatlow started to research and teaching of the metallurgical characteristics of weld. His pupil B.I Medovar led the development of a new metallurgical technology - electro-slag remelting.
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YE, ZHIYUN, JIANING LI, JUAN WANG, SHUBO XU, CAINIAN JING, YANHUA ZHAO, GUANCHAO LI, XINZHU GAN, FUKUN MA i FUSHENG YU. "LASER SURFACE REINFORCEMENT OF THE Ti/Al TIG WELDED JOINT". Surface Review and Letters 27, nr 12 (13.08.2020): 2050016. http://dx.doi.org/10.1142/s0218625x2050016x.
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The microstructure of the Ti/Al weld seam (WS) was uniform, and a good metallurgy bond between TC4/5052 aluminum alloy substrates was obtained without obvious defects after the Tungsten inert gas (TIG) process. Then, a remelt layer (RL) with fine microstructure can be formed by means of a laser remelting (LR) technique of the Ti/Al TIG joints. The Ti–Al intermetallics were produced adhered to the weld joints’ surface, exhibiting the extreme high surface hardness. The micro-hardness distribution of this RL surface was in a range of 1150–1200 HV[Formula: see text], which was significantly higher than that of the TC4 titanium alloy substrate. The high micro-hardness of the weld joints’ surface can be mainly ascribed to the actions of the Ti–Al intermetallics, the fine grain and the solid solution strengthening.
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Galkin, Yu A., E. A. Ulasovets, D. N. Obadin, D. V. Ermakov i A. N. Sharin. "Cleaning of concentrated emulsion sewage of electric-weld pipe lines". Ferrous Metallurgy. Bulletin of Scientific , Technical and Economic Information 77, nr 8 (21.10.2021): 943–48. http://dx.doi.org/10.32339/0135-5910-2021-8-943-948.
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Existing processes of cleaning emulsion sewage are based on either physicochemical technology with application of complex of reagents – nonorganic electrolytes and organic flocculants, resulting in obtaining highly-mineralized purified water, which cannot be used for technical water supply, or based on complicated technologies of electrocoagulation and ultrafiltration. This required elaboration of a new technology and equipment for cleaning concentrated emulsion sewage, in particular, those containing emulsol of Wedolit EP-5 grade, used for hydro-mechanical expanders of electric-weld pipe lines. The technology stipulates a successive introduction of a reagent – suspension of alumo-silicate based hard-phased sorbent and solution of flocculant of cation type Praestol-650ВС – into emulsion sewage, their mixing with emulsion water in a definite mode, sedimental differentiation of the formed phases in a precipitator-flocculator “ЭП ОФ”, gravitation concentration and dewatering of the obtained sediment at vacuumfilter. The dewatered sediment can be utilized in cement industry and metallurgy. It was shown that application of the hard-phase sorbent does not result in an increase of mineralization of purified water and enables to use it for technical purposes. The group of companies “ECO-PROJECT”, Ekaterinburg, accomplished a project for Chelyabinsk pipe-rolling plant, elaboration and manufacturing of equipment, as well as commissioning and start-up of the equipment. The elaborated technical solutions in the process of equipment running showed a high efficiency and can be used as a base for creation of facilities of any productivity for cleaning multi-type emulsion sewage at enterprises of various industries.
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Lou, Shumei, Yiming Li, Baojia Cheng, Lingwei Ran, Xuefeng Bai, Peng Chen i Qingbiao Wang. "Microstructural and Mechanical Properties of Longitudinal Welds in Porthole Die Extrudates of a 0.5 wt.% GNP/Al Composite". Metals 13, nr 3 (5.03.2023): 522. http://dx.doi.org/10.3390/met13030522.
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In this study, porthole die extrusion was performed on a graphene-nanoplatelet-reinforced aluminum composite (0.5 wt.% GNP/Al) prepared by powder metallurgy. The microstructure, grain size, microtexture, and mechanical properties of the composite extruded by the porthole die were studied. Along the extrusion direction, the tensile strength of the extruded composite was 139.7 MPa, and the elongation was 27.1%. Along the transverse direction, which included the weld zone, the tensile strength was 126.4 MPa, and the elongation was 24.1%. These values were 6.65% and 54.63% higher than those obtained for pure aluminum, respectively. Fractography along the extrusion direction revealed obvious ductile fracture characteristics; however, these were not so obvious along the transverse direction, mainly due to the anisotropy caused by the grain orientation of the extruded composite, thereby indicating that the composite exhibited excellent weld performance, which was further verified by Optical Microscope, Electron Backscattered Diffraction, and Transmission Electron Microscopeimages. Overall, these results indicate that GNP can contribute to the strength and toughness of composites in the weld zone in porthole die extrusions.
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Baskoro, Ario Sunar, Andreas Edyanto, Muhammad Azwar Amat i Hakam Muzaki. "Study on Nugget Growth in Resistance Spot Welding of Thin Aluminum A1100 Using Welding Simulation". Materials Science Forum 929 (sierpień 2018): 191–99. http://dx.doi.org/10.4028/www.scientific.net/msf.929.191.
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Resistance spot welding (RSW), generally which is one of the most often used to joint metal plate in the automotive and aviation industries. RSW welding process involves electrical, thermal mechanical, metallurgy, and complex surface phenomenon. Unlike the other welding processes, weld joint formation in RSW process occurs very quick (in milli-seconds) and took place between the workpieces overlap each other. Welding simulation allows visual examination of the weld joint without having to perform an expensive experiment. Weld nugget size is the most important parameter in determining the mechanical behavior of welded joints in RSW process. The quality and strength of the weld joint in RSW process is predominantly determined by the shape and size of the weld nugget. Simulation modeling of RSW process performed using ANSYS Parametric Design Language (APDL) module based on the finite element method (FEM), embedded in ANSYS Workbench. Electrical and transient-thermal interaction was developed to study the weld nugget growth on resistance spot welding of aluminum A1100 metal plate with a thickness of 0.4 mm respectively. Weld nugget diameter can be well predicted by using this simulation model from the temperature distribution during the welding process. Welding is performed by varying the weld current (1 kA and 2 kA) and the welding time for each electric current, which are start from 0.5, 1.0, and 1.5 cycle time. Nugget diameter for each of the welding parameters from the simulation modelling were 4,276 mm, 4,372 mm, 4,668 mm, 5,616 mm and 5,896 mm. Weld expulsion occurred for the specimen with welding current 2 kA and welding time 1.5 cycle time, characterized by the decreasing of the tensile-shear strength of the specimen.
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Sugianto, Riswanda, Kadir Harlian, Akhyar Akhyar, Aminur i Faslih Arman. "Numerical Simulation of Physical-Mechanical Properties Based on the Composition of GTAW Weld Metal Alloys with Dissimilar Base Metals". Key Engineering Materials 892 (13.07.2021): 150–58. http://dx.doi.org/10.4028/www.scientific.net/kem.892.150.
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Dissimilar weld-metal joints in aluminum alloys 5083 and 6061-T6 are often found in aircraft, railroad structures, ships, bridges, oil platforms, and building structures. However, welding of dissimilar metals is relatively more difficult due to the different metallurgy and thermophysical properties of the two alloys. The purpose of this study is to evaluate the physical-mechanical properties of the Tungsten Arc Welding (GTAW) process through numerical simulations of different welded joints between the 5083 and 6061-T6 aluminum alloys. The GTAW welding simulation process is carried out by 300 x 100 x 3 mm plate butt joints along 300 mm. GTAW weld metal is prepared for tensile test samples and metal alloy composition, the test is observed in the base metal and welded area. The results of the chemical composition test of the weld metal obtained that the composition is close to Al 5083 base metal so that the mechanical properties of the weld metal tend to be identical with Al 5083 alloy. The results of numerical simulation on the mechanical properties of GTAW weld metal at temperature conditions of 25 to 700 °C obtained several things, including 1) the range of thermal conductivity decreased from 174.393 to 86.424 W/mK. 2) The density increased from 2,348 to 2,663 gr/cm3. 3), the young modulus appears to decrease from 68,667 to 0 GPa. 4) the shear modulus decreases from 25,724 to 0 GPa. 5) the type of heat increases from 0.904 to 17,306 J/gK, and 6) the Poisson ratio increased from 0.335 to 0.5.
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de Albuquerque Santos, Vinícius. "CARACTERIZAÇÃO E ESTUDO COMPARATIVO ENTRE OS PROCESSOS GMAW E SMAW NA SOLDAGEM DE AÇO ESTRUTURAL ASTM A606, APLICADOS NA CONSTRUÇÃO CIVIL E MINERAÇÃO". Revista Científica Semana Acadêmica 9, nr 209 (17.09.2021): 1–32. http://dx.doi.org/10.35265/2236-6717-206-9144.
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The article makes a general study of Gas Metal Arc Welding (GMAW) and Solid Metal Arc Welding (SMAW) welding, welded on structural steel under the American Society for Testing and Materials (ASTM) A606. The welding process and its applicability in the construction and mining industry are presented. This work has as a starting point, the concepts of welding processes, thermal aspects involved, metallurgy, Thermally Affected Zone (ZTA), recurrent discontinuities and the result of mechanical tests. The material was welded to specimens in both processes. The mechanical test was evaluated, the anchoring in the bending of the material in the weld bead and characteristics of the weld quality. It was found that the material welded with SMAW showed greater tensile strength. It is also concluded, the greater hardness in the ZTA of the material welded with GMAW.
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Yao, Ze Kun, Chun Qin, Yong Quan Ning, Jing Xia Chao, Jian Wei Zhang, Zhong Gang Tan i Zhang Long Zhao. "Structure Evolving at Bonding Interface of Dual-Alloys Jointed with Different Method under Coupling Action of Heat and Force". Advanced Materials Research 668 (marzec 2013): 543–46. http://dx.doi.org/10.4028/www.scientific.net/amr.668.543.
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During near isothermal forging and heat treatment structure change of bonding interface in Ti3Al/TC11 and Ti2AlNb/TC11 dual alloys jointed with different method has been investigated. The results show that the solidification structure at dual-alloy joint welded by electron beam in vacuum has evolved into forging structure, columnar grains have been changed into equiaxed grains through breaking, crystal lattatice rebuild and re-crystallizing, and the mechanical bonding plus metallurgical bonding structure at joint welded by linear friction weld has transformed into metallurgy structure altogether, because constant high temperature during near isothermal forging can cause the diffusion of alloy elements and reconstruction of lattice structure.
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Ma, Zheng-Xiong, Pei-Xin Cheng, Jie Ning, Lin-Jie Zhang i Suck-Joo Na. "Innovations in Monitoring, Control and Design of Laser and Laser-Arc Hybrid Welding Processes". Metals 11, nr 12 (26.11.2021): 1910. http://dx.doi.org/10.3390/met11121910.
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With the rapid development of high power laser, laser welding has been widely used in many fields including manufacturing, metallurgy, automobile, biomedicine, electronics, aerospace etc. Because of its outstanding advantages, such as high energy density, small weld size, easy automation. Combining the two heat sources of laser and arc for welding can achieve excellent results due to the synergistic effect. Laser welding is a complicated physical and chemical metallurgical process, involving the laser beam and molten pool, keyholes and materials melting, evaporation and multiple physical process. Process monitoring and quality control are important content of research and development in the field of laser welding, which is the premise to obtain fine weld with high quality. Numerical simulation technology can describe many complex physical phenomena in welding process, which is very important to predict weld forming and quality and clarify the underline mechanism. In this paper, the research progress of process monitoring, quality control and autonomous intelligent design of laser and laser-arc hybrid welding based on numerical simulation were reviewed, and the research hotspots and development trends of laser welding in the future are predicted.
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Bunaziv, Ivan, Odd M. Akselsen, Xiaobo Ren, Bård Nyhus i Magnus Eriksson. "Laser Beam and Laser-Arc Hybrid Welding of Aluminium Alloys". Metals 11, nr 8 (21.07.2021): 1150. http://dx.doi.org/10.3390/met11081150.
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Aluminium alloys are widely used in many industries due to their high strength-to-weight ratios and resistance to corrosion. Due to their specific thermophysical properties and intricate physical metallurgy, these alloys are challenging to weld. Work-hardened alloys may experience strength loss in heat-affected zones (HAZ). The strength of precipitation-hardened alloys is severely damaged in both HAZ and weld metal due to coarsening or full dissolution. The high thermal conductivity and reflectivity of aluminium causes lower laser beam absorptivity with lower processing efficiency. Weld imperfections such as porosity, humping, and underfills are frequently formed due to the low melting point and density promoting high liquidity with low surface tension. Porosity is the most persistent imperfection and is detrimental for mechanical properties. In this work, extensive review was made on laser beam and laser-arc hybrid welding of aluminium alloys. Solidification cracking, evaporation of alloying elements, porosity and keyhole stability, and other challenges are studied in detail. The current development of laser welding of aluminium alloys is not so mature and new discoveries will be made in the future including the use of newly developed laser systems, welding consumables, welding methods, and approaches.
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Impero, Filomena, Fabio Scherillo, Antonello Astarita, Kathryn A. Beamish, Michele Curioni, Antonino Squillace i Xiao Rong Zhou. "Study of the Metallurgy of a Dissimilar Ti-6Al-4V – Stainless Steel Linear Fiction Welded Joints". Key Engineering Materials 651-653 (lipiec 2015): 1427–32. http://dx.doi.org/10.4028/www.scientific.net/kem.651-653.1427.
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This paper deals with the investigation of the metallurgy of a dissimilar Ti-6Al-4V-stainless steel joint linear friction welded. In particular two different stainless steel were considered: AISI 304 and AISI 316. These two alloys differs in the Molybdemun content. Metallographic observations, EDS analysis and Vickers Microhardness measurements were carried out, particular attention was focused on the study of the intermetallic compounds and on the microstructures of the different zones produced by the process. As usual for solid state welding processes, three different zones can be identified: the parent material, the heat affected zone (HAZ) and the thermo-mechanical affected zone (TMAZ), furthermore a very thin joining line, rich of intermetallic compounds, was also observed. In this zone diffusive phenomena also occurred resulting in a variation of the alpha phase content on the titanium side.In the TMAZ, the bimodal microstructure of the parent material was deformed and the presence of elongated alpha grains with broken beta-phase particles was established. Moreover it was observed that in the weld region, exposure to supertransus temperatures (995°C) combined with hot-deformation working and rapid cooling after joining induced the recrystallization of a martensitic beta grain structure. Concerning the joint between Ti-6Al-4V and AISI 316 some cracks were observed within the weld line, this due to the presence of brittle intermetallics compounds in this zone. The formation of these intermetallics was promoted by the presence of Molybdenum.
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Cieslak, M. J., i J. L. Jellison. "A Perspective on Welding Science". MRS Bulletin 14, nr 2 (luty 1989): 32–39. http://dx.doi.org/10.1557/s0883769400063417.
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Welding science is an interdisciplinary field involving metallurgy and materials science, heat, fluid, and mass transfer, and arc and plasma physics to name a few. Three areas of welding science have been the focus of much research the past few years as welding scientists attempt to understand the phenomena responsible for producing fusion welds with acceptable service properties. Broadly defined, these areas are:1. physical and numerical modeling of the heat and fluid flow during fusion welding,2. understanding the microstructural evolution during solidification and cooling of welds, and3. welding of advanced materials.This short review will focus on these fusion welding research themes to provide the reader with a flavor of the work in progress at several major government, industry, and university laboratories.Much of both the experimental and theoretical studies that have advanced the understanding of fusion welding processes revolves around delineating the roles of mass, momentum, and energy transfer. The earliest models of fusion welding processes were analytical models of heat transfer by conduction. These models not only excluded much of the physics of the process, but assumed point or linear heat sources. Nevertheless, these models provided useful insight about the interplay between power and weld speed, particularly regarding weld pool shape. Also, although quantitative predictions of weld pool shape were generally inaccurate, predicted thermal contours and cooling rates away from the fusion zone were useful in understanding the extent of heat-affected zones.
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Grujicic, M., J. S. Snipes, R. Galgalikar, S. Ramaswami, R. Yavari, C. F. Yen, B. A. Cheeseman i J. S. Montgomery. "Improved gas metal arc welding multi-physics process model and its application to MIL A46100 armor-grade steel butt-welds". Multidiscipline Modeling in Materials and Structures 10, nr 2 (5.08.2014): 176–210. http://dx.doi.org/10.1108/mmms-05-2013-0038.
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Purpose – The purpose of this paper is to develop multi-physics computational model for the conventional gas metal arc welding (GMAW) joining process has been improved with respect to its predictive capabilities regarding the spatial distribution of the mechanical properties (strength, in particular) within the weld. Design/methodology/approach – The improved GMAW process model is next applied to the case of butt-welding of MIL A46100 (a prototypical high-hardness armor-grade martensitic steel) workpieces using filler-metal electrodes made of the same material. A critical assessment is conducted of the basic foundation of the model, including its five modules, each dedicated to handling a specific aspect of the GMAW process, i.e.: first, electro-dynamics of the welding-gun; second, radiation/convection controlled heat transfer from the electric arc to the workpiece and mass transfer from the filler-metal consumable electrode to the weld; third, prediction of the temporal evolution and the spatial distribution of thermal and mechanical fields within the weld region during the GMAW joining process; fourth, the resulting temporal evolution and spatial distribution of the material microstructure throughout the weld region; and fifth, spatial distribution of the as-welded material mechanical properties. Findings – The predictions of the improved GMAW process model pertaining to the spatial distribution of the material microstructure and properties within the MIL A46100 butt-weld are found to be consistent with general expectations and prior observations. Originality/value – To explain microstructure/property relationships within different portions of the weld, advanced physical-metallurgy concepts and principles are identified, and their governing equations parameterized and applied within a post-processing data-reduction procedure.
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Rhode, Michael, Tim Richter, Dirk Schroepfer, Anna Maria Manzoni, Mike Schneider i Guillaume Laplanche. "Welding of high-entropy alloys and compositionally complex alloys—an overview". Welding in the World 65, nr 8 (14.04.2021): 1645–59. http://dx.doi.org/10.1007/s40194-021-01110-6.
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AbstractHigh-entropy alloys (HEAs) and compositionally complex alloys (CCAs) represent new classes of materials containing five or more alloying elements (concentration of each element ranging from 5 to 35 at. %). In the present study, HEAs are defined as single-phase solid solutions; CCAs contain at least two phases. The alloy concept of HEAs/CCAs is fundamentally different from most conventional alloys and promises interesting properties for industrial applications (e.g., to overcome the strength-ductility trade-off). To date, little attention has been paid to the weldability of HEAs/CCAs encompassing effects on the welding metallurgy. It remains open whether welding of HEAs/CCAs may lead to the formation of brittle intermetallics and promote elemental segregation at crystalline defects. The effect on the weld joint properties (strength, corrosion resistance) must be investigated. The weld metal and heat-affected zone in conventional alloys are characterized by non-equilibrium microstructural evolutions that most probably occur in HEAs/CCAs. The corresponding weldability has not yet been studied in detail in the literature, and the existing information is not documented in a comprehensive way. Therefore, this study summarizes the most important results on the welding of HEAs/CCAs and their weld joint properties, classified by HEA/CCA type (focused on CoCrFeMnNi and AlxCoCrCuyFeNi system) and welding process.
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Zhang, Dan, Jin Zhang, Shuchen Yang, Guoyou Shao i Zhongqiu Liu. "Element Transfer Behavior for CaF2-Na2O-SiO2 Agglomerated Flux Subject in Submerged Arc Welding Process". Processes 10, nr 9 (14.09.2022): 1847. http://dx.doi.org/10.3390/pr10091847.
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From a thermodynamic perspective, the present study has been performed to investigate the effect of SiO2 level in agglomerated fluxes on the element transfer behavior of essential elements, by applying CaF2-Na2O-SiO2 agglomerated fluxes with varying SiO2 contents. Element transfer behavior is quantified by the Δ value. The impact of SiO2 and heat input upon element transfer behavior is interpreted. Additionally, a possible thermodynamic approach to predict high basicity flux O potential and weld metal composition is proposed and evaluated. It is revealed that the consideration of the gas-slag-metal equilibrium is able to place constraints on the transfer behaviors (of O, Si, and Mn) and formation of gases. In submerged arc welding metallurgy, the empirically determined basicity index models proposed by Tuliani have been applied for more than 50 years to predict flux O potential and weld metal oxygen content. However, it is well known by welding practitioners that the flux basicity index model can only predict the changing trend of flux O potential when the flux basicity index is lower than 2.0. The present study has proposed a new thermodynamic method to identify the flux O potential for fluxes with a basicity index higher than 2.0. Additionally, the experimental evidence for the Mitra kinetic model has been provided.
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Zou, Cheng Lu, Gui Hong Geng i Wei Ye Chen. "Development and Application of Aluminium-Lithium Alloy". Applied Mechanics and Materials 599-601 (sierpień 2014): 12–17. http://dx.doi.org/10.4028/www.scientific.net/amm.599-601.12.
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The history of aluminium-lithium alloys development has been reviewed in this paper. According to the strength, weld ability and corrosion resistance, thermal stability and plasticity, aluminium-lithium alloy has been categorized and the defects of aluminium-lithium alloys in early stage have been analyzed. As compared the third generation of aluminium-lithium alloy with normal aluminum alloy and composite materials, it indicates aluminium-lithium alloy has better performance, lower cost and reduced weight. After analyzing the advantages and disadvantages of the rapid solidification, ingot casting metallurgy and electromagnetic simulated microgravity methods in synthesis of aluminium-lithium alloy, it has been found microgravity method has prominent effect on reducing the alloy segregation and lithium losses. Finally, the future development of aluminium-lithium alloys has been discussed.
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Gao, Zhiguo. "Thermal, Metallurgical and Mechanical Determinants of Laminar Nickel/Aluminum Dissimilar Alloys during Laser-material Interaction Part I: Nickel-based Superalloy". Journal of Physics: Conference Series 2348, nr 1 (1.10.2022): 012001. http://dx.doi.org/10.1088/1742-6596/2348/1/012001.
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To develop in-depth understanding of metallurgical phenomena for completeness, mechanical heterogeneity is kinetically and thermodynamically explained by thorough microstructure characterization of engineering materials, e.g. polycrystalline nickel-based superalloy, for alleviation of weldability-related problems during laser-induced keyhole fabrication. Because of nonequilibrium solidification behavior inside weld pool, finer γ phase dendrite substructure is confined to partition-resistant keyhole bottom part, coarser dendrite is crystallography-independently circumscribed at partition-vulnerable neck transition region of full penetration weld, and thus microstructure is lack of homogeneity. Abundance of segregation-driven eutectic phase or intermetallic phase in the interdendrite area throughout weld is essentially attributable to nonequilibrium solidification conditions, and morphologically increases susceptibility to mechanical properties deterioration. As a result of γ phase instability, Niobium-aided Laves/γ eutectic reaction in the vicinity of dendrite interstices at terminal stage of solidification contributes to severe dendrite boundaries brittleness, impairs mechanical properties, which is consistent with metallography and fractography results, and is more deleterious to weldability, since solute redistribution and supersaturation adversely exacerbate segregation behavior in the residual interdendrite liquid, especially asymmetric weld pool shape. There is inverse parabolic relationship between secondary dendrite arm spacing and solute partition coefficient, when location varies from nail-shaped weld upper site to bottom site. Chemical, microstructural and mechanical heterogeneities are more geometrically favorable in the curvature-related neck transition region. In addition, the mechanism of thermal, metallurgical and mechanical inhomogeneities, which are attributed to asymmetric weld pool shape, is consequently proposed. Untoward metallurgical phenomena, such as microstructure heterogeneity and brittle Niobium-rich Laves/γ eutectic phases mitigate strength, ductility and toughness of weld. In order to macroscopically and microscopically satisfy superior mechanical properties requirement, chemistry and microstructure of high quality weld are metallurgically controlled. Fruitful metallurgical information and mechanical data further support the reasonable explanations. It is imperative to progressively advance welding metallurgy, weldability and fabricability of intricate shape for welding defects minimization, suppress segregation and further develop mechanical properties through viable design and control of laser processing, simultaneously.
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Coetsee, Theresa, i Frederik De Bruin. "EERZ (Effective Equilibrium Reaction Zone) Model of Gas-Slag-Metal Reactions in the Application of Unconstrained Al-Ni-Cr-Co-Cu Metal Powders in Submerged Arc Welding: Model and 3D Slag SEM Evidence". Processes 11, nr 7 (14.07.2023): 2110. http://dx.doi.org/10.3390/pr11072110.
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The scope of this work is to improve the SAW process understanding and present an improved description of the SAW process in terms of gas-slag-metal reactions with alloy powder and Al powder additions. The scope does not include the materials properties of the weld metal. The latter may easily be optimised in the future by changing the weld metal chemistry once the process reactions of different element powders in SAW are understood. Aluminium as de-oxidiser element was applied to SAW to lower the oxygen partial pressure in the process. The results show the Al-Ni-Cr-Co-Cu alloyed weld metal total oxygen content was reduced to 257 ppm O, compared to the base case weld metal at 499 ppm O, made with the same flux and no metal powder additions. Thus, the aluminium that was added as a de-oxidiser element to the SAW process effectively lowered the original flux-induced partial oxygen pressure, both in the arc cavity and at the interface of the molten flux–weld pool phases. This partial oxygen pressure lowering effect of Al also prevents oxidation of Cr, preventing loss of Cr to the slag. Carbon steel was alloyed to 3.9% Al, 4.8% Ni, 4.9% Cr, 4.8% Co, 4.7% Cu at 62% Al yield, 76% Ni yield, 77% Cr yield, 75% Co yield, 74% Cu yield. SEM (scanning electron microscope) work on the three-dimensional (3D) post-weld slag sample show dome cavities with 3D rounded structures embedded in the dome cavity walls, as well as shards and nano-strands on the dome cavity walls. The 3D structures indicate vapour formation and re-condensation of oxy-fluorides. The novel application of the EERZ (effective equilibrium reaction zone) model simulates the mass transfer effects in the SAW process. This model is novel because it is the first model used to calculate the gas-slag-metal phase chemistry changes in SAW as a function of welding time. The novel SAW process modification of adding Al de-oxidiser powder with alloying element powders of the unique combination of Co-Cr-Co-Ni-Al was successfully applied. The results confirm that the gas phase and its reactions must be included in the interpretation and modelling of SAW process metallurgy.
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Rahul, S. G., R. Chitra i S. Kripa. "Instrumentation Based Microstructural Characterization of the Friction Stir Welded SiC/B4C Aluminium Metal Matrix Composites and Optimization of Governing Process Parameters". Journal of Computational and Theoretical Nanoscience 17, nr 7 (1.07.2020): 3277–92. http://dx.doi.org/10.1166/jctn.2020.9174.
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Aluminium Metal Matrix Composites reinforced with particulate silicon carbide and Boron Carbide reinforcements have demanding applications in aerospace and automotive domains. With a lack of sufficient literature on this composite combination and emerging demands, it is highly essential to understand their weldability and material characteristics. Friction Stir Welding is a feasible choice for joining of Aluminium Metal Matrix Composites over the conventional fusion welding owing to narrow Heat Affected Zone and minimized Intermetallic Compound formation at the weld interface. In this work, AA6061 matrix composite plates are fabricated with a varying weight percentage of particulate SiC and B4C reinforcements using powder metallurgy process. The study mainly focusses on the tensile strength, hardness and microstructural properties of composite plates joined using Friction Stir welding subjected to a constant load of 8KN at three-level process parameters experimental design of varying spindle speed, weld speed and plunge depth. The outcomes reveal sufficient information on the microstructural analysis of the weldments and the subsequent effects on the material strength. Followed by, statistical process parameter optimization is performed to improve the tensile properties of the weldments and the results are experimentally validated. The study confirms the feasibility and applicability of FSW in joining Al-MMCs.
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Sukanto, Wahyono Suprapto, Rudy Soenoko i Yudy Surya Irawan. "The effect of milling time on the alumina phase transformation in the AMCs powder metallurgy reinforced by silica-sand-tailings". EUREKA: Physics and Engineering, nr 1 (10.01.2022): 103–17. http://dx.doi.org/10.21303/2461-4262.2022.001906.
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This study aims to determine the effect of milling time and sintering temperature parameters on the alumina transformation phase in the manufacture of Aluminium Matrix Composites (AMCs) reinforced by 20 % silica sand tailings using powder metallurgy technology. The matrix and fillers use waste to make the composites more efficient, clean the environment, and increase waste utilization. The milling time applied to the Mechanical Alloying (MA) process was 0.5, 6, 24, 48, and 96 hours, with a ball parameter ratio of 15:1 and a rotation of 93 rpm. Furthermore, hot compaction was carried out using a 100 MPa two-way hydraulic compression machine at a temperature of 300 °C for 20 minutes. The temperature variables of the sintering parameter process were 550, 600 to 650 °C, with a holding time of 10 minutes. Characterization of materials carried out included testing particle size, porosity, X-Ray Diffraction (XRD), SEM-Image, and SEM-EDX. The particle measurement of mechanical alloying processed, using Particle Size Analyzer (PSA) instrument and based on XRD data using the Scherrer equation, showed a relatively similar trend, decreasing particle size occurs when milling time was increased 0.5 to 24 hours. However, when the milling time increases to 48 and 96 hours, the particle size tends to increase slightly, due to cold-weld and agglomeration when the Mechanical Alloying is processed. The impact is the occurrence of the matrix and filler particle pairs in the cold-weld state. So, the results of XRD and SEM-EDX characterization showed a second phase transformation to form alumina compounds at a relatively low sintering temperature of 600 °C after the mechanical alloying process was carried out with a milling time on least 24 hours
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Guo, Rui Peng, Lei Xu, Jie Wu, Zheng Guan Lu i Rui Yang. "Preparation and Welding Performance of Ti–6Al–4V Powder Compact Fabricated by Hot Isostatic Pressing". Materials Science Forum 849 (marzec 2016): 760–65. http://dx.doi.org/10.4028/www.scientific.net/msf.849.760.
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Powder metallurgy (P/M) Ti–6Al–4V alloy was produced by hot isostatic pressing from pre-alloyed powder in the present investigation. Electron beam welding (EBW) was used for butt joint of P/M Ti–6Al–4V sheets. Microstructure and tensile properties of P/M Ti–6Al–4V welded joint were studied. The results showed that the microstructure of the welded joint had a significant change due to the rapid cooling rate during the EBW process. The microhardness of the fusion zone was higher than that of other areas due to the occurrence of α' martensitic phase. The joint performance (tensile strength) was equal to that of weld matrix, and all of the tensile specimens failed in the base metal. For practical application of P/M Ti-based alloys, the ductility, strength and welding properties of materials could be optimized by proper microstructural design.
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Vemanaboina, Harinadh, Edison Gundabattini, Suresh Akella, A. C. Uma Maheshwer Rao, Ramesh Kumar Buddu, Paolo Ferro i Filippo Berto. "Mechanical and Metallurgical Properties of CO2 Laser Beam INCONEL 625 Welded Joints". Applied Sciences 11, nr 15 (29.07.2021): 7002. http://dx.doi.org/10.3390/app11157002.
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In the frame of the circular economy, welding of Ni-based superalloys has gained increasing importance when applied, for instance, to repairing highly expensive components widely used in strategical sectors, such as the defense and aerospace industries. However, correct process parameters avoiding metallurgical defects and premature failures need to be known. To reach this goal, Inconel 625 butt-welded joints were produced by CO2 laser beam welding and different combinations of process parameters. The experimental investigation was carried out with three parameters in two levels with an L4 orthogonal array. Laser power, welding speed, and shielding gas flow rate were varied, and the results were reported in terms of mechanical properties, such as microhardness, tensile strength, distortion, residual stress, and weld bead geometry, and metallurgy. At a lower welding speed of 1 m/min, the full penetration was observed for 3.0 kW and 3.3 kW laser powers. However, sound welds (porosity-free) were produced with a laser power of 3.3 kW. Overall, the obtained full-penetration specimens showed a tensile strength comparable with that of the parent material with residual stresses and distortions increasing with the increase in heat input.
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Sobhani, Samaneh, Marc Albert, David Gandy, Ali Tabei i Zhaoyan Fan. "Design Optimization of Hot Isostatic Pressing Capsules". Journal of Manufacturing and Materials Processing 7, nr 1 (25.01.2023): 30. http://dx.doi.org/10.3390/jmmp7010030.
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Power metallurgy hot isostatic pressing (PM-HIP) is a manufacturing technique capable of producing net shape or near-net shape components with complicated geometries from materials that are difficult to melt and cast, mechanically deform or weld. However, the process and soundness of the outcome are extremely sensitive to the geometric design of the capsule (also known as the die or can) that is used in the process. The capsule design for each new component involves several trial–error iterations to achieve the desired geometry and shape of the component. For each iteration, costly HIP experiments need to be conducted and new capsules need be manufactured with small modifications. In this study, a robust finite element analysis (FEA) model of the HIP process is developed, then wrapped in a multi-objective genetic algorithm (MOGA) optimization framework to obtain the optimal pre-HIP capsule design, which yields the desired post-HIP component geometry in one HIP run. The FEA-based optimization algorithm is validated by HIP experiments, showing excellent agreement between the experiment and the model.
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Pawlik, Jan, Michał Bembenek, Tomasz Góral, Jacek Cieślik, Janusz Krawczyk, Aneta Łukaszek-Sołek, Tomasz Śleboda i Łukasz Frocisz. "On the Influence of Heat Input on Ni-WC GMAW Hardfaced Coating Properties". Materials 16, nr 11 (25.05.2023): 3960. http://dx.doi.org/10.3390/ma16113960.
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Hardfacing is one of the techniques used for part lifecycle elongation. Despite being used for over 100 years, there still is much to discover, as modern metallurgy provides more and more sophisticated alloys, which then have to be studied to find the best technological parameters in order to fully utilize complex material properties. One of the most efficient and versatile hardfacing approaches is Gas Metal Arc Welding technology (GMAW) and its cored-wire equivalent, known as FCAW (Flux-Cored/Cored Arc Welding). In this paper, the authors study the influence of heat input on the geometrical properties and hardness of stringer weld beads fabricated from cored wire consisting of macrocrystalline tungsten carbides in a nickel matrix. The aim is to establish a set of parameters which allow to manufacture wear-resistant overlays with high deposition rates, preserving all possible benefits of this heterogenic material. This study shows, that for a given diameter of the Ni-WC wire, there exists an upper limit of heat input beyond which the tungsten carbide crystals may exhibit undesired segregation at the root.
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Katcher, Michael, i Dwaine L. Klarstrom. "A Review of Haynes® 230® and 617 Alloys for High Temperature Gas Cooled Reactors". Materials Science Forum 595-598 (wrzesień 2008): 511–17. http://dx.doi.org/10.4028/www.scientific.net/msf.595-598.511.
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HAYNES® 230® and 617 alloys are competing for use on Generation IV, high temperature gas cooled reactor components because of good high temperature creep strength in the temperature range between 760°C and 982°C and resistance to oxidation in the gas cooled reactor environment. A review of the metallurgy affecting the properties in each alloy will be discussed. Grain size and carbide precipitation developed during fabrication effect short term and long term ductility, fatigue, and creep. For example, 230 alloy has a finer grained structure which promotes fatigue strength with a slight sacrifice in creep strength. The 617 alloy has a coarser grain structure which provides slightly higher creep resistance while sacrificing some fatigue strength. Thermal aging also introduces gamma prime precipitation to the 617 alloy as well as grain boundary carbides, and this, in addition to grain boundary oxidation, reduces the low cycle fatigue strength of 617 alloy compared to 230 alloy. Independent studies have shown that 230 alloy possesses higher resistance to thermal fatigue than 617 alloy. However, welds of both base metals with similar weld composition have about the same thermal fatigue life. Cooling rates from solution annealing temperatures during processing effect the ductility and creep strength of these alloys with the highest cooling rates preferred for retention of ductility and creep strength. The reason; slow cooling rates promote carbide precipitation in the grain boundaries which reduces ductility and creep strength.
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Raj Kumar, R., i Surendra Patle. "Development of Heat Treatment Parameters to Enhance HAZ Impact Toughness of SS 430 Material". Advanced Materials Research 794 (wrzesień 2013): 214–21. http://dx.doi.org/10.4028/www.scientific.net/amr.794.214.
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Pressure Housing, used in the Grid Mechanisms Motor, is manufactured from ferritic stainless steel, SS430 bar of 120mm diameter. The application demands an alternative non-magnetic and magnetic material (austenitic and ferritic) on the outside. This is manufactured by making longitudinal machined slots on the outside surface of SS430 bar which is ferritic and magnetic and the machined slots are filled up by depositing SS347 which is an austenitic and non-magnetic stainless steel material. In order to weld SS430 # SS430 with SS347, welding procedure was to be qualified as per ASME Sec IX with additional requirements of impact specimens from weld and HAZ at temperature +20°C, microstructure examination and intergranular corrosion test as per ASTM A763 Pr.Z. It was the first time, SS430 # SS430 welding procedure qualification with SS347 was to be carried out as no earlier cases required this qualification. SS430 ferritic stainless steel bar exhibits stringers of ferrite and martensite and in cases of stingers of two phase structures like duplex stainless steel, it has been reported that the transverse impact properties drops to half to two-third the longitudinal values. In the welded coupon, the impact property on the HAZ was located in the transverse direction and extremely difficult to meet the requirements. Welding qualification with impact requirement in transverse direction in HAZ was a challenging task and this paper addresses the issues encountered and the work carried out in literature study on the metallurgy, heat treatment and experimental trials to meet the specification requirement.
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Coetsee, Theresa, i Frederik De Bruin. "Gas Formation of Cobalt and Copper in the Application of Unconstrained Co-Cr-Al-Cu Metal Powders in Submerged Arc Welding: Gas Phase Thermodynamics and 3D Slag SEM Evidence". Processes 11, nr 4 (5.04.2023): 1116. http://dx.doi.org/10.3390/pr11041116.
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Aluminium metal is not typically added to the submerged arc welding (SAW) process because it is easily oxidised to form unwanted slag in the weld pool. The successful application of aluminium as a de-oxidiser is illustrated in this study by preventing oxidation of Cr and Co to their oxides, thereby preventing element loss to the slag. Unconstrained pure metals of Al, Cr, Co and Cu were applied to investigate the gas formation behaviour of these elements in the SAW arc cavity. Of interest is the effect of copper in the arc cavity in terms of its possible substitution for aluminium. The results confirmed that the Al-Cr-Co-Cu alloyed weld metal total oxygen content was lowered to 176 ppm O, in comparison to 499 ppm O in the weld metal formed from welding with the original flux, which excluded metal powder additions. This lower ppm O value of 176 ppm O confirms that the added aluminium powder effectively lowered the original flux-induced partial oxygen pressure in the arc cavity, and at the molten flux–weld pool interface. Carbon steel was alloyed to 5.3% Co, 5.5% Cr, 5.3% Cu and 4.5% Al at 78% Co yield, 82% Cr yield, 78% Cu yield and 66% Al yield. Thermochemical equilibrium calculations confirm the partial oxygen pressure-lowering effect of aluminium when considering the gas–slag–alloy equilibrium. BSE (backscattered electron) images of the three-dimensional (3D) post-weld slag sample show dome structures which contain features of vapour formation and re-condensation. SEM-EDX (scanning electron microscope-energy dispersive X-ray) maps show that the dome surface matrix phase consists of Al-Mg-Ca-Si-Na-K-Ti-Fe-Mn oxy-fluoride. The spherical 3D structures of 10–40 µm in diameter consist of Fe-Mn-Si fluorides with some Cr, Cu and Co contained in some of the spheres. Cr and Co were observed in distinctive porous structures of approximately 10 µm in size, consisting partly of Cr oxy-fluoride and partly of Co oxy-fluoride. Nano-sized oxy-fluoride strands and spheres in the dome structures confirm vaporisation and re-condensation of oxy-fluorides. Cu and Na formed a distinct condensation pattern on the surface of the Si-Cu-Na-Mn-Fe-Co oxy-fluoride sphere. The results confirm the importance of including gas phase reactions in the interpretation of SAW process metallurgy.
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Parshin, Sergey G., i Peter Mayr. "Thermophysical Properties of Electric Arc Plasma and the Wire Melting Effect with Lanthanum and Sulfur Fluorides Addition in Wire Arc Additive Manufacturing". Metals 11, nr 11 (1.11.2021): 1756. http://dx.doi.org/10.3390/met11111756.
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Achieving a higher quality in wire arc additive manufacturing (WAAM) is a result of the development of welding metallurgy, the development of filler wires, and the control of the thermophysical properties of the electric arc. In this paper, the authors developed composite wires for WAAM with a Ni-LaF3, Ni-LaB6 coating. The addition of LaF3, LaB6, and SF6 increases specific heat, thermal conductivity, enthalpy, and degree of plasma ionization, which leads to the increase in the transfer of heat from the arc plasma to the wire and to the change in the balance of forces during wire melting. The increase in the Lorentz electromagnetic force and the decrease in the surface tension force made it possible to reduce the droplet diameter and the number of short circuits during wire melting. The change in the thermophysical properties of the plasma and droplet transfer with the addition of LaF3, LaB6, and SF6 made it possible to increase the welding current, penetration depth, accuracy of the geometric dimensions of products in WAAM, reduce the wall thickness of products, and refine the microstructure of the weld metal using G3Si1, 316L, AlMg5Mn1Ti, and CuCr0.7 wires.
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Kim, Kang-Hyung, Chan-Hyun Jung, Dae-Yong Jeong i Soong-Keun Hyun. "Causes and Measures of Fume in Directed Energy Deposition: A Review". Korean Journal of Metals and Materials 58, nr 6 (5.06.2020): 383–96. http://dx.doi.org/10.3365/kjmm.2020.58.6.383.
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Pores and cracks are known as the main defects in metal additive manufacturing (MAM), including directed energy deposition(DED). A gaseous fume is often produced by laser flash (instantaneous high temperature) during laser processing, which may cause various defects such as porosity, lack of fusion, inhomogeneity, low flowability and composition change, either. However the cause and harmful effects of fume generation in DED are known little. In laser processing, especially laser welding, many studies have been conducted on the prevention of fume because it generates defects that hinder uniform reactions between the laser beam and the materials. Generally, the fume occurs with easily vaporizing low melting point components or sensitive oxidizing elements. Unsuitable conditions are also known to have an effect, including laser power, travel speed, powder feed rate and shielding gas supply. Practically, there are many more fume generating factors in the DED process, and the lack of understanding requires a lot of trial and error. In this article the laser-related and weld metallurgy literatures were reviewed, focusing on the prevention of fume in powder DED. The causes of the fume, were explained to result from the stages of cavitation bubbles generated by the laser induced plasma and the nanoparticles released. Additionally, the effects of alloying components and environmental conditions for fume generation in the DED process were investigated, and suggestions are proposed to prevent fume.
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Pamungkas, Aftoni Heri Septian, Budi Harjanto i Indah Widiastuti. "ANALISIS KUALITAS REPAIR WELDING CAST WHEEL ALUMINIUM MENGGUNAKAN METODE PENGELASAN OKSI-ASETILIN DENGAN PERLAKUAN PREHEATING DAN POST WELD HEAT TREATMENT". NOZEL Jurnal Pendidikan Teknik Mesin 1, nr 1 (12.03.2019): 31. http://dx.doi.org/10.20961/nozel.v1i1.28280.
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<p><em>The aims of this research are to find out chemical composition, micro structure, the hardness </em><em>level</em><em>, and the strength impact of raw material and after welding using </em><em>preheating and post weld heat treatment </em><em>on cast wheel aluminum</em><em>.</em><em> Those data were analyzed using comparative descriptive method. The equipments used for measuring the chemical composition, microstructure, the hardness </em><em>level</em><em>, and the strength impact are as following: Spectrometer Metal Scan, Olympus Metallurgy</em><em> </em><em>Microscope, Vi</em><em>k</em><em>ers Hardness Tester and Charpy Tester. Based on the experiment results, it can be concluded that the chemical composition of the main constituent of cast wheel aluminum is 7,41% Si,</em><em> </em><em>which can be categorized in the aluminum alloy AA4343 series. The experiment results showed a decrease in the extent of the microstructure of primary Si phase after welding.</em><em> Si primary phase were spread well around the surface of </em> <!--?mso-application progid="Word.Document"?--> 12α"> -Al<em> </em><em>but the result Si </em><em>after oxy-acetylene </em><em>welding process </em><em>w</em><em>it</em><em>h</em><em> preheating and </em><em>PWHT indicates that the primary Si phase is reducing so that the α-Al phase is dominating</em><em>. </em><em>The hardness </em><em>level</em><em> on the welding result decreased from raw material amounted to 103.381 kgf/mm<sup>2</sup> be 40.112 kgf/mm<sup>2</sup> in the welding area and 44.378 kgf/mm<sup>2</sup> in area Heat Affected Zone (HAZ). The strength impact number on welding</em><em> </em><em>area showed a slight increase from the raw material areas of 0.055 joules/mm<sup>2</sup>to the welding of 0.058 joule/mm<sup>2</sup>. </em></p>