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1
Szymczak, T., G. Gumienny, I. Stasiak e T. Pacyniak. "Hypoeutectic Al-Si Alloy with Cr, V and Mo to Pressure Die Casting". Archives of Foundry Engineering 17, n. 1 (1 marzo 2017): 153–56. http://dx.doi.org/10.1515/afe-2017-0028.
Testo completoAbstract (sommario):
Abstract This paper presents the results of hypoeutectic 226 grade alloy as well as prepared on its basis Al-Si alloy containing Cr, V and Mo. The additives tested were added as AlCr15, AlV10 and AlMo8 master alloys. Alloys tested were poured into DTA sampler as well as using pressure die casting. An amount of Cr, V and Mo additives in alloy poured into DTA sampler comprised within the range approximately 0.05-0.35%. Alloys to pressure die casting contained 0.05-0.20% Cr, V and Mo. The crystallization process was examined using the derivative thermal analysis (DTA). The microstructure of castings made in the DTA sampler as well as castings made with use of pressure die casting were examined. The basic mechanical properties of castings made using pressure die casting were defined too. It has been shown in the DTA curves of Al-Si alloy containing approximately 0.30 and 0.35% Cr, Mo, and V there is an additional thermal effect probably caused by a peritectic crystallization of intermetallic phases containing the aforementioned additives. These phases have a morphology similar to the walled and a relatively large size. The analogous phases also occur in pressure die casting alloys containing 0.10% or more additions of Cr, V and Mo. The appearance of these phases in pressure die casting Al-Si alloys coincides with a decrease in the value of the tensile strength Rm and the elongation A. It has been shown die castings made of Al-Si alloys containing the aforementioned additives have a higher Rm and A than 226 alloy.
2
Daswa, Pfarelo, Heinrich Moller e Gonasagren Govender. "Overageing Characteristics of Alloy A356 and Al-Mg-Si Casting Alloys". Solid State Phenomena 285 (gennaio 2019): 75–80. http://dx.doi.org/10.4028/www.scientific.net/ssp.285.75.
Testo completoAbstract (sommario):
Al-Si-Mg casting alloys, such as Al-7Si-0.3Mg alloy A356, are heat treatable and can be precipitation hardened to the T6 temper condition. However, Al-Mg-Si casting alloys (5xx series) are generally not considered to be heat treatable. These 5xx series castings are known for good castability and good resistance to corrosion, especially in marine environments. This paper investigates the extent to which 5xx series alloys could possibly be artificially aged. The influences of artificial ageing time on the overageing characteristics of both Al-Mg-Si and A356 casting alloys have been studied. A356 aluminium alloy castings were produced using the CSIR rheo-high pressure die casting process (R-HPDC). Al-Mg-Si alloys were cast using permanent mould casting. The rate of overageing of these alloys is of importance for potential higher temperature applications. The overageing characteristics of Al-Mg-Si and A356 aluminium alloys have been investigated at an artificial ageing temperature of 190°C for ageing times up to 128 hours. It is shown that the rate of overageing of Al-Mg-Si casting alloys is lower than for alloy A356. This could possibly result in the use of these alloys in applications at temperatures that are higher than where alloy A356 can be employed. It also allows the possibility of using the 5xx series alloys as an alternative to other Al-alloys for R-HPDC applications.
3
Vanko, B., e L. Stanček. "Utilization of Heat Treatment Aimed to Spheroidization of Eutectic Silicon for Silumin Castings Produced by Squeeze Casting". Archives of Foundry Engineering 12, n. 1 (1 gennaio 2012): 111–14. http://dx.doi.org/10.2478/v10266-012-0021-1.
Testo completoAbstract (sommario):
Utilization of Heat Treatment Aimed to Spheroidization of Eutectic Silicon for Silumin Castings Produced by Squeeze Casting This paper describes the possibility of using very short periods of solution annealing in the heat treatment of unmodified hypoeutectic silumin alloy AlSi7Mg0,3 casted by method of casting with crystallization under pressure with forced convection (direct squeeze casting process). Castings prepared at different casting parameters were subjected to special heat treatment called SST (Silicon Spheroidization Treatment), which were originally used only for the modified silumin alloys to spheroidization of eutectic silicon. Temperature holding time in solution annealing of T6 heat treatment is limited in the SST process to only a few minutes. It was studied the effect of casting parameters and periods of solution annealing on ultimate strength, yield strength, and especially ductility that in the unmodified silumin alloy castings is relatively low.
4
Eperješi, Š., M. Matvija, ľ. Eperješi e M. Vojtko. "Evaluation of Cracking Causes of AlSi5Cu3 Alloy Castings". Archives of Metallurgy and Materials 59, n. 3 (28 ottobre 2014): 1089–92. http://dx.doi.org/10.2478/amm-2014-0187.
Testo completoAbstract (sommario):
Abstract Recently, the castings made from aluminum-silicon alloys by pressure die casting are increasingly used in the automotive industry. In practice, on these castings are high demands, mainly demands on quality of their structure, operating life and safety ensuring of their utilization. The AlSi5Cu3 alloy castings are widely used for production of car components. After the prescribed tests, the cracks and low mechanical properties have been identified for several castings of this alloy, which were produced by low pressure casting into a metal mould and subsequent they were heat treated. Therefore, analyses of the castings were realized to determine the causes of these defects. Evaluation of structure of the AlSi5Cu3 alloy and causes of failure were the subjects of investigation presented in this article.
5
Nadolski, M., Z. Konopka, M. Łągiewka e A. Zyska. "The Influence of the Method of Mould Filling on the Quality of Castings Made of EN AC-44000 or EN AC-46200 Alloy". Archives of Foundry Engineering 14, n. 4 (1 dicembre 2014): 73–76. http://dx.doi.org/10.2478/afe-2014-0089.
Testo completoAbstract (sommario):
Abstract The performed examinations concerning the process of filling the plaster ceramic moulds with aluminium alloys allowed to assess the influence of various methods of introducing the metal into the mould cavity on the macro- and microstructure of the obtained experimental castings. The comparison was performed for castings with graded wall thickness made either of EN AC-44000 alloy or of EN AC-46000 alloy, produced either by gravity casting, or by gravity casting with negative pressure generated around the mould (according to the Vacumetal technology), or by counter-gravity casting. It was found that the silicon crystals grow in size with an increase in wall thickness due to the slower cooling and solidification of castings
6
Vanko, Branislav, Ladislav Stanček, Michal Čeretka, Eduard Sedláček e Roman Moravčík. "Properties of EN AW-2024 Wrought Aluminum Alloy after Casting with Crystallization under Pressure". Scientific Proceedings Faculty of Mechanical Engineering 23, n. 1 (1 dicembre 2015): 58–65. http://dx.doi.org/10.1515/stu-2015-0009.
Testo completoAbstract (sommario):
Abstract Establishing of wrought aluminum alloys casting to manufacture is now a global trend, for example due to lower production costs compare to forging or due to the ability to produce parts with thinner sections and more complex shapes. The aim of using these alloys in the foundry industry is in particular the creation of castings with higher mechanical properties than achieve castings made of standard casting aluminum alloys. Most often are cast wrought aluminum alloys of the 2xxx, 6xxx and 7xxx series. In the experiment, an alloy EN AW-2024 has been cast by modified technology of casting with crystallization under pressure. They were measured basic mechanical properties of the castings in the as-cast state and after heat treatment.
7
Říhová, M., J. Cech e J. Havlíčková. "Evaluation of Porosity in Al Alloy Die Castings". Archives of Foundry Engineering 12, n. 1 (1 gennaio 2012): 93–98. http://dx.doi.org/10.2478/v10266-012-0018-9.
Testo completoAbstract (sommario):
Evaluation of Porosity in Al Alloy Die Castings Mechanical properties of an Al-alloy die casting depend significantly on its structural properties. Porosity in Al-alloy castings is one of the most frequent causes of waste castings. Gas pores are responsible for impaired mechanical-technological properties of cast materials. On the basis of a complex evaluation of experiments conducted on AlSi9Cu3 alloy samples taken from the upper engine block which was die-cast with and without local squeeze casting it can be said that castings manufactured without squeeze casting exhibit maximum porosity in the longitudinal section. The area without local squeeze casting exhibits a certain reduction in mechanical properties and porosity increased to as much as 5%. However, this still meets the norms set by SKODA AUTO a.s.
8
Wang, Yingli, e Fengxian Wang. "Key Analysis of Design and Numerical Simulation for Aluminum Alloy Impeller Low-pressure Casting Mold". Journal of Physics: Conference Series 2338, n. 1 (1 settembre 2022): 012070. http://dx.doi.org/10.1088/1742-6596/2338/1/012070.
Testo completoAbstract (sommario):
Abstract It is of great practical value to complete the low-pressure casting of aluminum alloy impeller in the current development of low-pressure casting process. In the research, it is necessary to focus on factory realization and use low-pressure casting to produce aluminum alloy impellers, so that impeller castings with compact structure and meeting performance requirements can be obtained. Compared with other casting methods, low-pressure casting itself, as a precision casting method, can be cast on the metal solution with lower pressure in the application process. The castings can be filled and solidified under certain pressure, and the castings with compact structure can be obtained. In the research, Pro / Engineer is used to design the low-pressure casting mold for aluminum alloy impeller, and MAGMASOFT is used to carry out the filling and solidification process of aluminum alloy impeller. Through numerical simulation, we can accurately predict the defects of impeller castings, and optimize the mold scheme and pressure-time parameters according to the prediction results.
9
Guan, Tian Yang, Zhi Feng Zhang, Min He, Yue Long Bai e Ping Wang. "Effects of Annular Electromagnetic Stirring Melt Treatment on Microstructure and Mechanical Properties of 7050 Rheo-Casting". Solid State Phenomena 285 (gennaio 2019): 219–23. http://dx.doi.org/10.4028/www.scientific.net/ssp.285.219.
Testo completoAbstract (sommario):
The microstructure and mechanical properties of 7050 alloy rheo-castings after treated by Annular Electromagnetic Stirring (A-EMS) melt treatment were investigated. The results revealed that, under A-EMS, the refinement and homogeneity of the solidification structure could be improved greatly and the slurry was suitable for the following rheo-casting; and also the hot-cracking defects in the casting process were significantly alleviated, meanwhile, the strength and ductility of the alloy casting were found to be comparable to those of conventionally forged 7000 series alloys.
10
Liu, Yan Gai, Zhao Hui Huang, Hao Ding, Ming Hao Fang e Shou Mei Xiong. "Study on Pressure Variations in the Mold of Magnesium Alloy Die Castings". Key Engineering Materials 353-358 (settembre 2007): 1614–16. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.1614.
Testo completoAbstract (sommario):
High pressure die casting is the most common method in making magnesium alloys for both auto parts and 3C products. Pressure variations in the mold during mold filling and solidification process have direct influences on the quality and properties of die castings. In this paper, a cylinder head cover was produced to experimentally study pressure variations in the mold during magnesium alloy die-casting process in real time for the first time. Pressure varies at different positions in the mold during die casting process. This study indicates that mold filling and solidification process of magnesium alloy die castings can be described by pressure curves obtained by pressure measurement at different test positions in the cavity in real time.
11
Wang, Xue Dong, Jian He Lin, Suo Qing Yu e Li Yong Ni. "Casting Mold Designing for Aluminum Alloy Car Holders". Applied Mechanics and Materials 378 (agosto 2013): 350–54. http://dx.doi.org/10.4028/www.scientific.net/amm.378.350.
Testo completoAbstract (sommario):
The structure and processing of car holders castings were analyzed. Die-casting molding process scheme was established. The design of mold includes three core-drawing mechanisms. the gate of the gating system was arranged on the casting bottom surface. For economy and die easy maintenance considerations, die-casting machine, mold, and mold standard parts should be standard parts. The designs of mold gating system and non-standard pieces were completed with the aid of PROE. Proved by actual production, the mold operated smoothly, without clamping stagnation, and the production of die castings meet delivery requirements.
12
Majerič, Dragana, Vojkan Lazić, Peter Majerič, Aleksa Marković e Rebeka Rudolf. "Investigation of CoCr Dental Alloy: Example from a Casting Workflow Standpoint". Crystals 11, n. 8 (22 luglio 2021): 849. http://dx.doi.org/10.3390/cryst11080849.
Testo completoAbstract (sommario):
Cobalt-chromium (CoCr) alloys have been used in dentistry for dental bridges, crowns and implants for decades. When using CoCr alloys, a number of fractures have occurred in the Dental Laboratory, both when handling the castings and after they have been placed in the patient’s mouth. It is assumed that the key cause of the resulting fractures of CoCr dental bridges is the casting process, which includes the preparation and mixing of the basic components of the CoCr dental alloy, unstable solidification and the final treatment of the tooth casting surface. The aim of this study was, therefore, to examine three castings differently prepared from the CoCr alloy. For the initial CoCr alloy, we selected the one supplied directly from the manufacturer; three test samples were CoCr alloy remelted four times in the same crucible, while the fourth sample was the remaining solidified alloy from the crucible, taken at the last remelting. Characterisation of the microstructure of all four samples was performed by optical and scanning electron microscopy equipped with an energy dispersive X-ray spectroscope and X-ray diffractometry. Microhardness measurements were also performed. The investigation revealed that the microstructure of the castings is composed of a CoCr alloy matrix with a eutectic interdendritic composition and interdendritic precipitates, which were rich in W and Mo. The two oxides were identified as chromium oxide with silicon content and chromium oxide, which originated from the CoCr alloy as casting residue. The high content of silicon in the chromium oxide can be attributed to the silicon oxide from the ceramic melting crucible, mixed in with the remains from the CoCr alloy melting. The second oxide showed a more regular elemental content for chromium oxide, mixed with a small quantity of impurities and the casting CoCr alloy. Based on this research, some recommendations were made for working with CoCr alloys in the Dental Laboratory, with the aim of reducing the risk of dental bridge fractures in the future.
13
Taute, Carlien, e Heinrich Möller. "Segregation Characteristics of Rheo-High Pressure Die Cast Al-Alloy 2139 Plates". Materials Science Forum 828-829 (agosto 2015): 100–105. http://dx.doi.org/10.4028/www.scientific.net/msf.828-829.100.
Testo completoAbstract (sommario):
Al-Cu-Mg-Ag alloy 2139 is a wrought alloy that is heat-treatable and used in aerospace constructions. This is mainly due to the addition of silver in the alloy. Hot-tearing is a problem for casting wrought alloys with conventional liquid casting techniques. The risk is reduced by using rheo-high pressure die casting (R-HPDC) to allow the alloy to be used for near-net shape forming of components. This study investigates the segregation characteristics of R-HPDC alloy 2139. The effects of segregation on the age-hardening response as well as the tensile properties are studied. The chemical composition differences across the casting were found to aid in correlation of results. It is found that segregation occurs in three dimensions, namely from the surface to the centre of the casting, as well as across the width and length of the casting.
14
Dybowski, B., A. Kiełbus e R. Jarosz. "Mould Components Impact on Structure and Quality of Elektron 21 Alloy". Archives of Foundry Engineering 13, n. 2 (1 giugno 2013): 17–23. http://dx.doi.org/10.2478/afe-2013-0029.
Testo completoAbstract (sommario):
Abstract Magnesium alloys due to their low density and high strength-to-weight ratio are promising material for the automotive and aerospace industries. Many elements made from magnesium alloys are produced by means of sand casting. It is essential to investigate impact of the applied mould components on the microstructure and the quality of the castings. For the research, six identical, 100x50x20mm plates has been sand cast from the Elektron 21 magnesium casting alloy. Each casting was fed and cooled in a different way: one, surrounded by mould sand, two with cast iron chills 20mm and 40mm thick applied, another two with the same chills as well as feeders applied and one with only the feeder applied. Solid solution grain size and eutectics volume fraction were evaluated quantitatively in Met-Ilo program, casting defects were observed on the scanning electron microscope Hitachi S3400N. The finest solid solution grain was observed in the castings with only the chills applied. Non metallic inclusions were observed in each plate. The smallest shrinkage porosity was observed in the castings with the feeders applied.
15
Znamenskii, L. G., A. N. Franchuk e A. A. Yuzhakova. "Nanostructured Materials in Preparation Casting Alloys". Materials Science Forum 946 (febbraio 2019): 668–72. http://dx.doi.org/10.4028/www.scientific.net/msf.946.668.
Testo completoAbstract (sommario):
The article deals with technologies of refining and inoculating casting alloys with the use of nanostructured diamond powder, as well as stimulation technique on molten metal including processing of the liquid alloy with nanosecond electromagnetic pulses. The developed method of cast iron inoculation allows to eliminate the flare and to increase the physical and mechanical properties of the castings through the grain refining and the decrease of chilling tendency during crystallization of the liquid alloy. Inoculating of aluminium alloys by high-melting particles of a nanostructured diamond powder leads to the grinding of structural constituents, including conditions for dispersing hardening intermetallics during postbaking of such castings. As a result, foundry and physicomechanical properties of castings are significantly improved.
16
Liao, Dun Ming, Li Liang Chen, Jian Xin Zhou e Rui Xiang Liu. "CAD/CAE Technology and its Application on Nonferrous Alloy Casting". Advanced Materials Research 139-141 (ottobre 2010): 1113–16. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.1113.
Testo completoAbstract (sommario):
The nonferrous alloy castings will be much demanded with the development of aerospace, light-weight weapons and automotive industry. Casting CAD/CAE technology has played an increasingly important role in foundry. It can help technician to design casting process and simulate heat transferring and molten metal flowing before actual production. Firstly, the main contents and basic principles, mathematical models of casting CAD and CAE were introduced. Secondly, the casting CAD/CAE technology route was interpreted, and then several CAD/CAE applications of casting process design and simulating were carried out on nonferrous alloys, such as aluminum, magnesium and copper. The results indicate that CAD/CAE technology can be applied to casting process design and predict casting defects which usually occur during the casting mold filling and solidification process, it can provide references to optimize casting process, so as to improve casting quality, reduce the rejection rate and shorten the development cycle of new products.
17
Kocurek, Robert, e Janusz Adamiec. "Structural Stability of Welded Joints of Magnesium Alloy EZ33A-T5". Materials Science Forum 782 (aprile 2014): 408–14. http://dx.doi.org/10.4028/www.scientific.net/msf.782.408.
Testo completoAbstract (sommario):
Magnesium alloys of Mg-Zn-RE-Zr group are characterized by creep resistance up to 250°C, good castability, absence of the microporosity and gas corrosion resistance. Defect of these alloys are low mechanical properties at ambient temperature. Magnesium alloys are used in the automotive, aerospace and defense industries, mainly as gravitational casts to sand moulds or die-casting. Casting defects often appear in these casts (misruns, micro-shrinkage, cracks), especially for large-size castings. The welding technologies are most often applicable to repair of casts, mainly non-consumable electrode welding in the inert-gas cover. Welded joints made of magnesium alloys should have properties at least the same as the ready cast, in particular it should ensure stability of the structure and properties of all welded joint in working temperature. In the literature there is a lack of information about stability and properties of welded joints of Mg-4E-3Zn (EZ33A-T5 acc. to ASTM B80) alloy castings. In research work determined the structure of welded joints of Mg-4RE-3Zn alloy casting after stress-relief annealing and defined changes of structure and properties during long-term annealing at the temperature of 250°C. It was found that the structure of welded joint of casting alloy Mg-4RE-3Zn is stable at the temperature of 250°C through at least 1000 hours. The hardness of tested joints equal 80 HV. Therefore welding technologies can be used for repair of magnesium alloy casts with addition of zinc and rare earth elements.
18
Ozyegin, L. S., R. Tuncer e E. Avci. "Hardness, Behavior and Metal Surface Evaluation of Recasting Non-Precious Dental Alloys". Key Engineering Materials 330-332 (febbraio 2007): 1425–28. http://dx.doi.org/10.4028/www.scientific.net/kem.330-332.1425.
Testo completoAbstract (sommario):
Recasting of economic alloys can change several properties. The number of recasting was found to have negligible effect on surface texture and on the amount of corrosion products released. The methods and equipments utilized in the casting of an alloy are important on the quality of casting. Carbon incorporated in a noble or economic alloy during casting is known to affect the mechanical values of the metal. In the present study we aimed to investigate the change in structure and metal hardness due to recasting. Materials and method: The effect of recasting, up to four times of a non precious “Finalloy” commercial dental alloy on their Rocwell C hardness behavior and their microstructures was inspected. Using “Kerr casting waxes” patterns were prepared similar to the samples from “Finalloy”. The investments were pre-heated to phase at temperatures between 900°C and 1000°C. The alloy was melted by an acetylene-oxygen flame in a silicate crucible and four groups were compared: New alloy and alloys casted two, three, and four times (n = 7). After casting, Brinell harnesses were recorded. Values of Rocwell C strength, for each specimen group were analyzed by one-way analysis of variance, followed by the Student- Newman-Keuls multiple range test. A metal microscope was used to evaluate the surface morphology of the samples before hardness tests. 1st Casting :30.65 ± 0.3 kgf, 2nd Casting: 31.33 ± 0.4 kgf, 3rd Casting:34.80 ± 0.3 kgf, 4th Casting: 35.5 ± 28 kgf represents the Rocwell hardness of the castings. The results showed that hardness, increased with repeated castings. The experimental data indicates that increasing the number of successive recasting of “Finalloy” enhances the Rocwell C hardness, thus, after remelting and recasting, the biological properties decreases. Microscope study: Increase of the carbon content on the gren bounders of a cobalt-chromium alloy causes a considerable change in its microstructure. The hardness and yield point for 0.05 %, 0.1 % and 0.2 % tensile strength and elongation were determined for these test-pieces. The results showed that hardness, yield points and tensile strength increased with increased carbon content, whereas the elongation lessened. We determined that carbon concentrated at gren bounders. The clinical importance of the study is that recasting affected the properties of the metal, for best biological results with dental alloys always new metals must be used.
19
Prikhod’ko, O. G., V. B. Deev, E. S. Prusov e A. I. Kutsenko. "Influence of thermophysical characteristics of alloy and mold material on castings solidification rate". Izvestiya. Ferrous Metallurgy 63, n. 5 (1 luglio 2020): 327–34. http://dx.doi.org/10.17073/0368-0797-2020-5-327-334.
Testo completoAbstract (sommario):
Obtaining castings of given quality is the main task of foundry production. One of the stages of casting technology is solidification of melt in the mold. When studying the process of castings solidification, it is necessary to fully take into account all the features of heat transfer between casting and mold. Influence of various thermophysical parameters of alloy and mold material on casting formation is considered. In the analysis, original mathematical models were used to calculate the coefficient and time of complete solidification of castings in sand-clay and metal forms. These models take into account geometric parameters of casting, main thermophysical parameters of casting metal and mold material, heat transfer conditions at crystallization front, on casting-mold boundary and on the mold surface. Analysis of dependence of time and rate of castings solidification on thermophysical parameters (heat capacity, density, heat conductivity of casting material and mold, specific heat of metal crystallization) was carried out. Storage capacity and process of heat storage are quite fully characterized by the value of heat storage coefficient. This coefficient practically determines the rate of heat loss by the casting which plays a decisive role in its properties forming. Therefore, this parameter is selected for a comprehensive analysis of thermal processes occurring in casting and mold. The influence of thickness and thermal conductivity of chill paint layer on solidification of castings in metal molds is considered. The basic calculation formulas and initial data are presented. Calculations were carried out for castings of the following types: endless plate, endless cylinder, ball. The results of simulation of solidification process parameters are presented in graphic form. Using various alloys as an example, it has been shown by calculation that when changing composition and properties of mold material, it is possible to change time and speed of alloys solidification in a wide range. In this case, processes of forming the structure and properties of castings are controlled.
20
Chirita, G., I. Stefanescu, Delfim Soares e F. S. Silva. "Effect of Gravity/ Vibration/ Centrifugal Process on Mechanical Properties of an Al-Si Alloy". Materials Science Forum 587-588 (giugno 2008): 395–99. http://dx.doi.org/10.4028/www.scientific.net/msf.587-588.395.
Testo completoAbstract (sommario):
On this paper, a study that evaluates the influence of some variables on the mechanical properties of the vertical centrifugal casting is made. It is emphasized the fact that the centrifugal effect from vertical centrifugal casting brings special features on mechanical properties. It has been observed that the centrifugal effect may substantially increase, in some alloys, the rupture strength, rupture strain, and Young modulus, as compared to the gravity casting technique. When compared to gravity casting, the centrifugal casting process, besides the centrifugal force (pressure effect), always has an inherent associated vibration during the casting. In this study, as an attempt to isolate the vibration effect from the overall centrifugal effect, tests on castings obtained by vibrating gravity casting process are made. A comparison between castings obtained by centrifugal casting technique, vibrating casting technique and gravity casting technique is made in order to fully understand the features that allow the improvement on mechanical properties during the vertical centrifugal casting technique. An analysis of the most important effects, on both mechanical properties and on some metallurgical features is made.
21
Qi, Ming Fan, Yong Lin Kang, Yuan Hao Zheng, Ji Cheng Wang, Gu Nan Li e Ying Zhang. "Industrialization of Aluminum Alloy Uniform Solidification Controlled Rheological Die Casting". Solid State Phenomena 327 (10 gennaio 2022): 163–71. http://dx.doi.org/10.4028/www.scientific.net/ssp.327.163.
Testo completoAbstract (sommario):
An efficient and low-cost aluminum alloy uniform solidification control technology, namely, air-cooled stirring rod (ACSR) process, has been developed for preparing large volume semisolid slurry. The semisolid slurry preparation process is connected with the die-casting machine to form multiple integrated intelligent rheological die-casting production lines for the efficient preparation of rheological die-casting of large-scale thin-walled aluminum alloys. At present, the ACSR process can produce 40 kg of large-volume semisolid slurry with a solid phase ratio of 25% to 35% within 30 s. This rheological die-casting process has been industrialized for the preparation of high-quality aluminum alloy large-scale thin-walled parts, such as new energy vehicles and 5G communications. Typical products produced by this process include heat dissipation housings for 5G communications, filter housings, antenna chassis and three-electric structural shell, end cover, and ABS system valve body for new energy vehicles. Compared with traditional die castings, aluminum alloy castings prepared by the new process not only have fine and spherical microstructures, good surface quality, and fewer internal pores but also enjoys more excellent mechanical properties and thermal conductivity.
22
Yang, Guang Yu, Wan Qi Jie, Qi Tang Hao e Jie Hua Li. "Study on Process of Magnesium Alloy Investment Casting". Materials Science Forum 561-565 (ottobre 2007): 1019–22. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.1019.
Testo completoAbstract (sommario):
The process of different sorts of magnesium alloys investment casting is studied using a mold materials composed of zircon and colloided silica binder. The investment shell is flushed out employing protective gas mixture of 1% HFC134a and inert gas. The castings with perfect appearance and high metallurgical quality are produced successfully for ZC62 and ME-1magnesium alloy respectively. The mechanical properties of the castings reached the ASTM standard.
23
He, Li Tong, Yi Dan Zeng e Jin Zhang. "Solidification and Microstructure Simulation of A356 Aluminum Alloy Casting". Materials Science Forum 1033 (giugno 2021): 18–23. http://dx.doi.org/10.4028/www.scientific.net/msf.1033.18.
Testo completoAbstract (sommario):
To obtain an A356 aluminum alloy casting with a uniform structure and no internal shrinkage defects, ProCAST software is used to set different filling and solidification process parameters for an A356 aluminum alloy casting with large wall thickness differences, And multiple simulations are conducted to obtain optimized casting process; then, based on the process, the microstructure of the thickest and thinnest part of the casting are simulated. The size, morphology, and distribution of the simulated microstructure of the thinnest part and the thickest part of the casting are very similar. The simulated microstructure is similar to that of the actual casting. This shows that castings with uniform structure and no internal shrinkage defects can be obtained through the optimized casting process .
24
Visik, E. M., L. I. Rassokhina, A. B. Echin e M. V. Gamazina. "Some aspects of improving the quality of GTE cast turbine blades of nickel superalloys". Voprosy Materialovedeniya, n. 4(108) (31 gennaio 2022): 82–98. http://dx.doi.org/10.22349/1994-6716-2021-108-4-82-98.
Testo completoAbstract (sommario):
The results of the development of casting technology for single-crystal high-pressure turbine blades from nickel superalloys with a crystallographic orientation (CGO) [001] were obtained on an automated casting unit for directional crystallization UVNK-9A, at machine-building enterprise. The construction of the casting blades blocks, technologies for the manufacture of molds, rods and casting of GTE working blades of heatresistant nickel alloys with a single-crystal structure and set-up CGO have been developed under real production conditions on UVNK-9A units substituting through-type furnaces. It is shown that preproduction series of single-crystal castings of working blades with shroud shelf were obtained, with a yield of suitable structure ≥ 75%. The structural-phase characteristics of the alloy of single-crystal blades castings were investigated by scanning electron microscopy in as cast state and after subsequent heat treatment. A comparative quantitative analysis of the microstructure and strength characteristics of supernickel alloy castings with CGO [001], obtained on a high-gradient directional crystallization unit and in a through-type furnace.
25
Cheng, Le, Hong Xing Lu, Qiang Zhu, Xiang Kai Zhang, Ai Di Shen e Peng Yang. "Evolution of Microstructure and Mechanical Properties of Semi-Solid Squeeze Cast A356.2 Aluminum Alloy during Heat Treatment". Solid State Phenomena 285 (gennaio 2019): 139–45. http://dx.doi.org/10.4028/www.scientific.net/ssp.285.139.
Testo completoAbstract (sommario):
Semi-solid squeeze casting (SS-SC) is a new processing technology which combines semi-solid processing (SSP) and squeeze casting (SC). In this process, semi-solid slurry fills mold by using its rheological property and solidifies under high pressure. It has several advantages, such as stable filling, small heat impact to the mold, low cost, high density and excellent mechanical properties of castings, which receives more and more attention. The microstructure of castings provided by SS-SC is quite different from that of casting provided by conventional SC in as-cast condition, which leads to differences in the evolution of microstructure and mechanical properties in heat treatment process. In this study, A356.2 aluminum alloys castings were provided by both SS-SC and conventional SC respectively. The evolution of microstructure and mechanical properties of castings during heat treatment was investigated to obtain the best mechanical properties of semi-solid squeeze castings. Keywords:Microstructure, Mechanical properties, Heat treatment, A356 alloy, Semi-Solid Squeeze Casting
26
Gaspar, Stefan, e Jan Pasko. "Increase Pressure and Homogeneity of Die Castings from EN AC 47100 Alloy". Applied Mechanics and Materials 729 (gennaio 2015): 108–13. http://dx.doi.org/10.4028/www.scientific.net/amm.729.108.
Testo completoAbstract (sommario):
In the pressure die casting process, a great attention is paid to a die castings quality improvement. This quality has to be ensured with a great reliability and, at the same time, it is necessary to apply control methods to a technological process which provide a complete picture of a die casting process as well as internal quality of the produced die castings. It requires control of the present technological factors of a pressure die casting process. The contribution deals with the effect of die casting plunger velocity inside a filling chamber on mechanical properties of a die casting product from EN AC 47100 alloy.
27
Władysiak, R. "Effect of Multipoint Sequential Water Mist Cooling of Casting Die on Microstructure and Mechanical Properties of AlSi11 Alloy". Archives of Foundry Engineering 12, n. 4 (1 dicembre 2012): 145–50. http://dx.doi.org/10.2478/v10266-012-0123-9.
Testo completoAbstract (sommario):
Abstract The work is a continuation of research on the use of water mist cooling in order to increase efficiency of the die-casting process for aluminum alloys. The paper describes the multipoint sequential cooling system of the casting die and its computer control and monitoring. It also includes results of the tests and analysis of cooling methods during making of the casting. These methods differ from each other in the sequence of casting die cooling and cause effective changes in microstructure and mechanical properties of castings made of AlSi11 alloy. The study demonstrated that the use of multipoint sequential cooling with water mist affects the microstructure refinement and reduces the segregation in the cast as well as more than by 20% increases the mechanical properties of castings in the rough state. The study also demonstrates that the sequential cooling of casting die accelerates the cooling of the casting and shortens die-casting cycle.
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Krishnan, Arjun Bala, Kavin Selvaraj, Akhil Madhusoodhanan Geethakumari e Ravi Manickam. "Effect of Heat Treatment on the Microstructure of Gravity Cast and Squeeze Cast Al-Si-Mg Alloy". Materials Science Forum 830-831 (settembre 2015): 164–67. http://dx.doi.org/10.4028/www.scientific.net/msf.830-831.164.
Testo completoAbstract (sommario):
The present work deals with the effect of solutionising heat treatment on the features of Al-7Si-0.3Mg (A356) alloy in terms of microstructural modifications and hardness. The microstructure of sand cast and gravity cast alloys are coarse which results in lower strength compared to the alloys cast using modern casting techniques such as squeeze casting which is used for the fabrication of near-net-shaped castings. The influence of enhanced cooling rate on the hardness and microstructure of the squeeze casting technique has been exploited in the present study. In order to optimise the heat treatment process, the microstructure of the gravity and squeeze cast alloys were compared after solution treatment. The quantitative analysis of the microstructure was carried out using an image analyser attached to the optical microscope. The aspect ratio, particle count and circularity of eutectic silicon and SDAS are measured. The squeeze cast alloy is found to have finer microstructure with enhanced properties compared to the gravity cast alloy.
29
Kordas, P. "Influence of the conditions of casting and heat treatment on the structure and mechanical properties of the AlMg10 alloy". Journal of Achievements in Materials and Manufacturing Engineering 1, n. 83 (1 luglio 2017): 26–32. http://dx.doi.org/10.5604/01.3001.0010.5137.
Testo completoAbstract (sommario):
Purpose: Assessment of the possibilities of shaping the structure and improvement of mechanical properties of casting from AlMg10 alloy through a selection of casting technology and precipitation hardening. Design/methodology/approach: the work evaluated the impact of casting and heat treatment technology on the mechanical properties and structure of AlMg10 alloy castings. The tests were performed on 200 mm × 100 mm × 25 mm plate castings produced by gravity casting methods for sand and metal moulds and by a liquid state press moulding technology. Castings made with these technologies solidify in substantially different heat- evaporation conditions and exhibit varying degrees of primary structure fragmentation. Metallographic and strength tests were performed on raw castings and after heat treatment. Findings: The changes in the morphology and size of primary crystals and the dispersion of the reinforcing phase according to the casting solidification rate and the precipitation hardening treatment were analyzed. Solidifying castings in the form of sand show a globular structure, whereas in die and press castings, a typically dendritic structure occurs, with the dendritic crystals in pressed castings being much smaller in size than the die castings. In castings which were not heat-treated, the reinforcing phase of Al3Mg2 occurs in interdendritic spaces, and its dispersion increases with the rate of cooling. After supersaturation and ageing treatments, the phase α has a grain structure in all samples. The largest dispersion of reinforcing molecules is characterized by press castings. In a raw state, the highest mechanical properties are shown by castings made in the form of sand and the method of pressing in a liquid state. Heat treatment of AlMg10 alloy castings significantly influences the increase of mechanical indexes in all castings investigated. The highest features of Rm are approx. 330 MPa and A5 above 10% is obtained in castings made by the press method. Research limitations/implications: Particular attention should be paid to the avoidance of the effects of slag inclusion, shrinkage and magnesium oxidation during casting of AlMg10 alloys. In die castings of a plate type, due to own stresses, a significant decrease in mechanical properties occurs. Practical implications: The most advantageous mechanical properties of AlMg10 alloy castings are obtained by using liquid-state pressing technology. In addition, this technology makes it possible to produce thin-walled castings of high dimensional accuracy, high air- tightness, fine grain structure, lack of surface defects and low roughness. Originality/value: The paper presents the possibility of improving the mechanical properties of AlMg10 castings by applying heat treatment. It has been proven that the casting method has a significant effect on the mechanical properties of the castings.
30
Amenova, Aliya, e Dauletkhan Smagulov. "Optimization of the Compositions of the High Strength Casting Aluminium Alloys Based on Nickel Eutectic". Advanced Materials Research 911 (marzo 2014): 152–57. http://dx.doi.org/10.4028/www.scientific.net/amr.911.152.
Testo completoAbstract (sommario):
The phase composition of the AlNiMnFeSiZr system was analyzed with respect to new-generation heat resistant casting aluminum alloys based on a Ni-containing eutectic, which are strengthened by the Al3Zr (L12) nanoparticles. It is shown that the presence of iron and silicon considerably complicates the phase analysis compared with the AlNiMnFe base alloy. Alloys with low silicon content have a sufficiently good casting property, which enables fabrication of thin-walled castings, not inferior to AA356 alloy types widely used to cast complex shapes. Addition of silicon to the AlNiMnFe base alloy sharply deteriorates hot cracks. Silicon greatly decreases the solubility of Zr at (Al), which is reflected on hot brittleness of Al2%Ni1%Mn0,5%Fe-0,2%Zr system alloys.
31
Fracchia, Elisa, Ivano Gattelli e Marco Actis Grande. "Characterisation of Residual Stresses of Rheocast Al Alloy". Solid State Phenomena 347 (24 agosto 2023): 31–37. http://dx.doi.org/10.4028/p-cq6pqs.
Testo completoAbstract (sommario):
Rheocasting is a semisolid casting process allowing to obtain near-net shape parts. Through the Rheocasting process, it is possible to achieve aluminium castings having a low grade of porosity if compared to traditional die-casting methods, encouraging the production of automotive frame parts. However, casting processes, as commonly known, may cause tensile residual stresses inside the parts. On the other hand, compressive stresses inside castings can significantly increase the life of components: residual compressive stresses increase the material's resistance by counteracting crack initiation and propagation. The cracks propagate when the material is under tensile stress, while the Rheocasting technique seems to promote compressive stresses inside the castings. This work aims to analyse an aluminium rheocasted frame component for race cars in both the as-cast and heat-treated conditions. First, the mechanical properties of the components were evaluated in terms of tensile tests and microhardness. Then, residual stresses were measured at specific points of the casting. Finally, the evolution of the residual stresses inside the component before and after heat treatment led to assessing the effect of the Rheocasting process condition and the heat treatment, proving the marked advantage of using such a technology.
32
Kim, Myoung Gyun, Gyu Chang Lee e Joon Pyo Park. "Continuous Casting and Rolling for Aluminum Alloy Wire and Rod". Materials Science Forum 638-642 (gennaio 2010): 255–60. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.255.
Testo completoAbstract (sommario):
Since the Continuous Casting & Rolling of the non-ferrous metal by Illario Properzi have invented in 1944, the various non-ferrous rod, wire and sheet are produced at present. Although there is long research and trials for producing the wire or rod of commercial the high-strength aluminum alloy, there are few companies with the success in producing commercial hard-aluminum alloys wire and rod by CC&R process. The application of the high-strength aluminum alloy rod or wire is various parts such as rivet, bolt, sports leisure supplies, high-tension power transmission wire, machinable and forgeable materials. However, it is very difficult to produce the high-strength aluminum alloy wire and rod by CC&R process because of the wide mushy zone and high strength compared with the pure or low strength aluminum alloy. Additionally, it is easy to crack and breakout in casting and rolling process due to tiny internal defects of the castings. The object of this project is to design the most suitable equipments for CC&R and optimize the experimental condition of continuous casting condition of the high-strength aluminum alloy. The facilities of CC&R process in RIST are composed of the melting furnace, the wheel casting machine, the automatic machine for moving of castings bar, the 15-step rolling machine with three rolls, the induction heater for reheating the castings bar and the coiling machine. In the present work, through the numerical computer simulation, in first, we have developed the thermal model of the solidification behavior of the casting bar. Finally, using finite element code, Marc, the temperature distribution of each rolled bar and effective strain are obtained during continuous rolling.
33
Drotlew, A., M. Garbiak e B. Piekarski. "Cast Steels for Creep-Resistant Parts Used in Heat Treatment Plants". Archives of Foundry Engineering 12, n. 4 (1 dicembre 2012): 31–38. http://dx.doi.org/10.2478/v10266-012-0103-0.
Testo completoAbstract (sommario):
Abstract Creep-resistant parts of heat treatment furnaces are in most cases made from high-alloyed chromium-nickel and nickel-chromium iron alloys, both cast and wrought. This paper presents the types of casting alloys used for this particular purpose, since the majority of furnace components are made by the casting process. Standards were cited which give symbols of alloy grades used in technical specifications by the domestic industry. It has been indicated that castings made currently are based on a wider spectrum of the creep-resistant alloy grades than the number of alloys covered by the standards. Alloy grades recommended by the technical literature for individual parts of the furnace equipment were given. The recommendations reflect both the type of the technological process used and the technical tasks performed by individual parts of the furnace equipment. Comments were also made on the role of individual alloying elements in shaping the performance properties of castings.
34
Koltygin, A. V., V. E. Bazhenov, S. A. Tavolzhanskii, S. V. Matveev, I. V. Plisetskaya, M. V. Belov, A. V. Samokhin e V. D. Belov. "Production of filler rods for repair welding of ML12 (ZK51) magnesium alloy castings". Izvestiya Vuzov. Tsvetnaya Metallurgiya (Universities' Proceedings Non-Ferrous Metallurgy), n. 3 (15 giugno 2022): 47–56. http://dx.doi.org/10.17073/0021-3438-2022-3-47-56.
Testo completoAbstract (sommario):
In magnesium alloys castings, the casting defects such as shrinkage porosity are often occur. Such defects can be suppressed by repair welding or surfacing using a special filler rod. Unfortunately, in Russia, the low amount of filler rod is consumed. Therefore, native enterprises do not manufacture it, limiting themselves to imports or homemade low-quality substitutes. Nevertheless, there is a need for filler rod, and recently it has become unprofitable to replace them with imported materials due to a significantly increased price. Therefore, there is a need to study the technology of its production to replace imported filler rod with native material. Magnesium alloys based on the Mg–Zn–Zr (La, Nd) system: SV1, SV122, and ML12 (ZK51) that used as a filler rod for repair welding of ZK51 alloy castings were studied in this work. The samples were obtained by permanent mold casting into aluminum molds followed by hot extrusion into a filler rod with a diameter of 4 mm. It was shown that all the investigated alloys could be obtained in the form of a rod with a diameter of 4 mm. Therefore, the investigated rod samples from the SV122 alloy were used as filler material for repair welding of ZK51 magnesium alloy castings. The weld seam in the T1 condition has an ultimate tensile strength (UTS) about 80 % of the UTS of the casting material.
35
Hussainy, Syed Ferhathullah, Mohd Viquar Mohiuddin, P. Laxminarayana, S. Sundarrajan e A. Krishnaiah. "Analysis of Shrinkage Characteristics of Aluminium Silicon Alloy". Journal for Manufacturing Science and Production 16, n. 3 (1 settembre 2016): 163–71. http://dx.doi.org/10.1515/jmsp-2016-0002.
Testo completoAbstract (sommario):
AbstractAnalysis of shrinkage characteristics of Aluminium-Silicon alloy was studied theoretically and experimentally. The Aluminium alloys considered in the study are A413 (LM6), A360 (LM9) and A380 (LM24). Extensive literature survey has suggested that cavity filling and solidification process are two most critical aspects to produce high quality casting components. A statistical model of parameters and response to understand the influence of parameters on shrinkage and casting yield studies has been presented. Experiments were conducted in foundry in industrial environment to produce commercially treated aluminium alloy castings in sand mould. Alloy was found to be most significant factor influencing shrinkage. The yield of casting was improved using insulating and exothermic sleeves. Solidification time of exothermic riser was 10 % more than insulated riser. Thus, in order to produce radiographic quality casting a theoretical and experimental method is presented so that number of trials in foundry is reduced which leads to increased reliability and productivity. Study also shows that by using sleeves considerable metal is saved, energy saving during melting, improved quality, reduced cost and increased capacity of plant can be achieved.
36
Hu, Wu, Ke Zhu, Meng Wang, Wei Dong Huang e Jian Min Zeng. "Study on Linear Segregation of ZL205A Alloy". Materials Science Forum 1020 (febbraio 2021): 8–12. http://dx.doi.org/10.4028/www.scientific.net/msf.1020.8.
Testo completoAbstract (sommario):
Linear segregation of high strength aluminum alloy ZL205A castings were studied by X-ray Nondestructive testing, scanning electron microscope and energy dispersive spectrometer. It is found that the linear segregation occurs at the large wall thickness of the casting and/or at the place where the wall thickness is in transition. Segregation element is mainly Cu, which exists as compound θ (Al2Cu) phase. The formation of linear segregation is related to the flow of Cu-rich melt in the late solidification period, while the occurrence of thermal cracks promotes the formation of linear segregation. The formation of linear segregation of the casting can be effectively prevented by eliminating hot spots of the casting, refining crystal grains and increasing solidification speed of the casting.
37
Sekar, K., Allesu Kanjirathikal e M. A. Joseph. "Comparison Study of As-Cast and T6 Condition of Microstructure, Bending Strength and Double Shear Strength of A356 Alloy by Gravity, Vacuum and Squeeze Casting". Applied Mechanics and Materials 592-594 (luglio 2014): 102–5. http://dx.doi.org/10.4028/www.scientific.net/amm.592-594.102.
Testo completoAbstract (sommario):
The hardness, bending strength, and double shear strength of A356 aluminium alloy was studied under as cast and T6 heat treatment conditions obtained with gravity casting, vacuum casting and squeeze casting methods. The results of these three casting methods have been compared. The hardness, bending strength of A356 alloy after T6 obviously increased; the hardness value of both vacuum casting and squeeze casting has been found to be 62 HRB which is relatively high compared to gravity casting. The bending strength of gravity casting is 299 MPa (22% increase) compared to vacuum casting. However, after T6 heat treatment, the double shear strength values of all these three castings decreases.
38
Won, Chun-Soo, Jae Pil Jung, Kwang-Sik Won e Ashutosh Sharma. "Technological Insights into the Evolution of Bronze Bell Metal Casting on the Korean Peninsula". Metals 12, n. 11 (22 ottobre 2022): 1776. http://dx.doi.org/10.3390/met12111776.
Testo completoAbstract (sommario):
Bronze cast bells have been designed and developed for hundreds of years, with the worldwide spread of several faiths and religions such as Buddhism, Catholicism, and Protestantism. The exceptional ringtones of bronze bell metals have scientific healing and cultural importance. In this review article, we highlight the evolution of bronze bell metal over the decades, its composition, and the complex fabrication technologies used to date. Furthermore, we overview ancient and modern casting alloy technology, especially bronze bell castings in Asia. The bell shape, materials, and alloy casting technology have undergone dramatic change over the years. For comparison, we include different bronze cast bells and their characteristics produced from the Middle Ages to the present times. Based on the data obtained from the bell casting technology surrounding the Korean Peninsula, the major trends in the evolution of bronze bell castings and long-standing traditions of mold materials and alloys are described. In the present review, the effects of different elements on bell materials are qualitatively overviewed, with an assessment of the material and casting properties, service life, and bell sound. We also highlight the challenges of conventional bronze casting and possible solutions for future investment castings and rapid prototyping of bronze bells.
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Bobba, Sujith, Sambasiva Rao Mukkollu, Z. Leman e Harish Babu Bachina. "Experimental Investigation on the Effect Due to Mould Vibrations on Mechanical and Metallurgical Properties of Aluminum Alloy (A-1050)". International Journal of Surface Engineering and Interdisciplinary Materials Science 9, n. 1 (gennaio 2021): 77–86. http://dx.doi.org/10.4018/ijseims.2021010105.
Testo completoAbstract (sommario):
In the current research work performed, the consequences caused in the casting aluminum alloy specimen due to mechanical mould vibrations are examined. Mould vibration throughout the casting provides decreased rate of shrinkage, good morphology, surface finish and lesser probability of hot tear. In this research work, the effect of mould vibration during solidification of Aluminum A-1050 alloys for dissimilar values of wavelengths at a permanent pouring temperature has been investigated to understand the modification in microstructure and mechanical properties after casting. The Al A-1050 casting has been made in a metal mould with different vibrations. The frequencies are varied from 15Hz to 50 Hz during the casting process. A casting has been made with different vibration as well to compare the results of castings with vibration frequencies. The experimental outcomes exhibited substantial grain refinement and significant increase in tensile strength and hardness of the castings with mechanical mould vibration during the duration and after solidification.
40
Adamiec, Janusz. "The Quantitative Assessment of the Fracture Profile of Magnesium Alloy QE22 Welded Joint". Solid State Phenomena 197 (febbraio 2013): 215–20. http://dx.doi.org/10.4028/www.scientific.net/ssp.197.215.
Testo completoAbstract (sommario):
Magnesium alloys are a part of a group of lightweight and ultra-lightweight alloys, which are important in practical use in constructions. QE22 casting magnesium alloy containing silver, rare earth elements and zirconium is characterized by creep resistance up to the temperature of 200 °C, while during a short exposure it can resist up to the temperature of 250°C. Nowadays, QE22 magnesium alloy are used for casting into sand moulds. In castings of magnesium alloys defects or inconsistencies (such as casting misruns, porosities and cracks) often appear, particularly in huge dimensional castings. Such defects are repaired with the use of padding and welding. Welded joints must ensure suitable operational properties, mainly in terms of creep, so that the repaired casting can work under the same conditions as the correct cast. The basic source of information about the cause and cracking propagation is fracture after creep test. The quantitative fractography, in particular profilomety, allows to describe the fracture and basis on it conclude the causes of destruction. In this paper quantitative procedure for assessing the fracture profile of QE22 welded joints after creep test was worked out. Base on its analysis result, it was found that creep resistant of the QE22 joints is determined by eutectic areas, therefore they must be heat treated after welding joints.
41
SUN, ZHI, YANWEI SUI, AIHUI LIU, BANGSHENG LI e JINGJIE GUO. "RESEARCH OF MECHANICAL PROPERTY GRADIENT DISTRIBUTION OF Al-Cu ALLOY IN CENTRIFUGAL CASTING". Surface Review and Letters 18, n. 06 (dicembre 2011): 297–301. http://dx.doi.org/10.1142/s0218625x11014795.
Testo completoAbstract (sommario):
Al-Cu alloy castings are obtained using centrifugal casting. The regularity of mechanical property gradient distribution of Al-Cu alloy castings with the same centrifugal radius at different positions is investigated. The result shows that the tensile strength, yield strength, elongation and microscope hardness exhibit the following gradient distribution characteristic — high on both sides and low on the center. The trend of mechanical property gradient distribution of Al-Cu alloy increases with the increase in the rotation speed. Moreover, the mechanical properties of casting centerline two sides have asymmetry. The reason is that the grain size of casting centerline two sides and Al2Cu phase and Cu content change correspondingly.
42
Shao, Heng, Yan Li, Peng Zhao, Hai Nan e Qing Yan Xu. "Numerical Simulation of Centrifugal Casting Process of Large Thin-Wall Ti Alloy Casting". Materials Science Forum 850 (marzo 2016): 469–81. http://dx.doi.org/10.4028/www.scientific.net/msf.850.469.
Testo completoAbstract (sommario):
Centrifugal pouring is often used in investment casting of large thin-wall Ti castings to promote filling. Shrinkage defects often appear in a Ti casting produced by centrifugal casting. Numerical simulation indicate that shrinkage is caused by these reasons: improper pouring system and thin-wall structure limited feeding of liquid metal from pouring system, and centrifugal force enlarged the shrinkage defects by strengthen feeding of liquid within the casting. Thus centrifugal casting is replaced by gravity casting and a new pouring system is adopted. Obvious shrinkage defects disappear in the new casting process.
43
Liu, De Fang, e Jie Tao. "Application of Automobile Lightweight Alloys and the Development of its Die-Casting Technology". Advanced Materials Research 308-310 (agosto 2011): 785–89. http://dx.doi.org/10.4028/www.scientific.net/amr.308-310.785.
Testo completoAbstract (sommario):
With the development of lightweight vehicles, lightweight alloy materials has been increasingly used in automotive industry, automobile manufacturers are therefore looking for thinner and stronger materials so that the higher requirements has became a challenge to lightweight alloy die-casting technology. The paper summarized the applications of lightweight alloys in the automotive industry, and the new advances of lightweight alloys die-casting technology, such as low pressure die-casting, semi-solid die casting, oxygenation die-casting and the combination of different die-casting technologies, and discussed the development trend of the lightweight alloy die-casting technology.
44
Gaspar, S., e J. Pasko. "Pressing Speed, Specific Pressure and Mechanical Properties of Aluminium Cast". Archives of Foundry Engineering 16, n. 2 (1 giugno 2016): 45–50. http://dx.doi.org/10.1515/afe-2016-0024.
Testo completoAbstract (sommario):
Abstract Recent research in the process of aluminum alloy die castings production, which is nowadays deeply implemented into the rapidly growing automobile, shipping and aircraft industries, is aimed at increasing the useful qualitative properties of the die casting in order to obtain its high mechanical properties at acceptable economic cost. Problem of technological factors of high pressure die casting has been a subject of worldwide research (EU, US, Japan, etc.). The final performance properties of die castings are subjected to a large number of technological factors. The main technological factors of high pressure die casting are as follows: plunger pressing speed, specific (increase) pressure, mold temperature as well as alloy temperature. The contribution discusses the impact of the plunger pressing speed and specific (increase) pressure on the mechanical properties of the casting aluminum alloy.
45
Yang, Xiang Jie, Yi He, Yong Bo Zhu, Chuan Lin Hu, Hong Min Guo, Yun Hai Jing e Guang Bin Yi. "The Study of A356 Alloy Rheo-Squeeze Casting Process". Solid State Phenomena 256 (settembre 2016): 270–75. http://dx.doi.org/10.4028/www.scientific.net/ssp.256.270.
Testo completoAbstract (sommario):
In this paper, the castings of A356 alloy were made by the rheo-squeeze casting with slurry-making from the process of LSPSF. Experiments were designed to study the influence of three parameters in rheo-squeeze casting process, such as injection speed, mould preheating temperature and injection pressure, on castings performance. The results show that high-quality castings were produced with the injection speed of 0.5m/s ,the mould preheating temperature of 240°C, the injection pressure of 50MPa. The mechanical properties, such as the yield strength, tensile strength and elongation of the castings with T6 heat treatment are 241 MPa, 328MPa and 11.6%, respectively.
46
Niakan, Ali Asghar, M. H. Idris, A. Ourdjini e Majid Karimian. "Effect of Applying Air Pressure on Gas Porosity in Lost Foam Casting of Al-Si Alloy". Advanced Materials Research 628 (dicembre 2012): 150–55. http://dx.doi.org/10.4028/www.scientific.net/amr.628.150.
Testo completoAbstract (sommario):
The paper presents the result of investigation on aluminum-silicon (LM6) alloy cast using pressurized lost foam casting process. The study investigated the effect of pressure and sand size on porosity of the casting produced. Air pressure of 1, 2, 3 and 4 bars was applied on the solidifying alloy poured in mould of sand sizes 16-30, 40-60, 60-100 (AFS). The porosities of casting were measured using optical microscope which was equipped with image analyzer. For porosity of castings, all surfaces of solidified castings were captured by digital camera for better observation. The results show that applying pressure during solidification of the LM6 alloy has significant influence on casting porosity of the alloy. By increasing the applied pressure, the porosity percentage based on gas porosity decreased when pressure was applied. Consequently, the removal rate of gas porosity improved by increasing the sand size to finer size 60-100 (AFS), so there is less gas porosity in samples. Besides, rising air pressure lead to fulfilling of molten which improves the casting porosity.
47
Xu, Yong Tao, Tian Yang Guan, Zhi Feng Zhang, Yue Long Bai e Wei Min Mao. "Semi-Solid Rheological Squeeze Casting Process of ZL114A Aluminum Alloy Thin-Wall Complex Casting". Materials Science Forum 993 (maggio 2020): 248–53. http://dx.doi.org/10.4028/www.scientific.net/msf.993.248.
Testo completoAbstract (sommario):
High-strength aluminum alloy with large-scale and thin-walled complex castings have broad application prospects in aerospace, weapons, electronics, defense and military industries. However, due to the uneven thickness of the plate, the casting defects are inevitable by the ordinary casting method, and it is impossible to accurately control the shape and performance of the casting in the casting process. Previous studies have found that the semi-solid rheological extrusion casting technology with short process and near-end type can help solve this technical problem. Therefore, this paper studies the semi-solid rheological extrusion casting process of thin-walled complex casting of ZL114A aluminum alloy. The combination of numerical simulation and experimental research is used to simulate and optimize the filling and solidification process of thin-walled specimens. Based on this, a semi-solid rheological extrusion casting test was conducted. The result showed that, (1) The optimized model can well reflect the filling and solidification process under different rheological extrusion casting parameters, and obtain defect-free castings through process optimization. (2) The thin-walled parts of the thin plate casting produced by semi-solid rheology extrusion have excellent mechanical property and ductility.
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Kierzek, Agata, e Janusz Adamiec. "Creep Resistance of WE43 Magnesium Alloy Joints". Solid State Phenomena 191 (agosto 2012): 177–82. http://dx.doi.org/10.4028/www.scientific.net/ssp.191.177.
Testo completoAbstract (sommario):
Magnesium alloys of Mg-Y-RE-Zr series are characterized by creep resistance up to a temperature of 250 ° C, and can work up to a temperature of 300oC. These properties allow for the application of alloys of Mg-Y-RE-Zr series for the elements of racing car engines operating in the conditions of high loads and temperatures. The requirement of high reliability components of aircraft propulsion system, with high strength and corrosion resistance, also led to the use of these alloys in the aerospace industry. Welding technologies in cast magnesium alloys are applied in order to repair defects in castings, occurring in the casting process, as well as to regenerate worn out castings. Joints made of magnesium alloys should have at least the same properties as a finished casting. The literature lacks information on the properties of joints welded of cast magnesium alloys.This work includes examination of influence of heat treatment on creep resistance of alloy WE43. Material for the study comprised joints made by the TIG method, welded in the cast state. Creep tests were carried out on joints without heat treatment and joints after heat treatment. The tests were performed at the temperatures of 200 ° C and 250 ° C during 100h. It was found that there is an increase in creep resistance of the joints after heat treatment.
49
Vanko, Branislav, Ladislav Stanček e Roman Moravčík. "EN AW-2024 Wrought Aluminum Alloy Processed by Casting with Crystallization under Pressure". Strojnícky casopis – Journal of Mechanical Engineering 67, n. 2 (1 novembre 2017): 109–16. http://dx.doi.org/10.1515/scjme-2017-0024.
Testo completoAbstract (sommario):
AbstractBy using the wrought aluminum alloys can be created castings with higher mechanical properties than the castings made of standard foundry aluminum alloys, but it is necessary to handle the process of making sound castings without any defects such as hot tears and shrinkage porosity. In experiments, we have been studied of wrought aluminum alloy EN AW-2024 which has been processed by the casting with crystallization under pressure with forced flow. Castings were heat treated by standard T6 heat treatment.
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Shang, Shu Zhen, Jiao Jiao Wang, Gui Min Lu e Xiao Ling Tang. "Study on the Semi-Solid Thixo-Diecasting Process of Aluminum Alloys and Die Design". Solid State Phenomena 192-193 (ottobre 2012): 460–65. http://dx.doi.org/10.4028/www.scientific.net/ssp.192-193.460.
Testo completoAbstract (sommario):
The constitutive equation of semi-solid 6061 alloy was established according to the thermal simulation compression tests of semi-solid billet of 6061 alloy prepared by near-liquids semi-continuous casting method. Parameters of Bingham model, such as apparent viscosity, had been investigated based on the constitutive equation of semi-solid 6061 alloy. The software ANYCASTING was applied to simulate and analyze the semi-solid die-casting processes of semi-solid 6061 alloy. A well-designed runner and gating system of automobile aluminum alloy part were presented and the casting defect were investigated here utilizing these parameters by simulation. The results show that a well-designed runner and gating system is very important to secure good quality die castings through providing a homogenous mould filling pattern. Most defects of semi-solid casting products can be founded in the final solidification of the parts of casting.