Aluminum Alloy Billets Research Articles

Improving the quality of cold-rolled deformable aluminum alloy billets

A mode of high-speed recrystallization annealing has been developed to increase technological plasticity while maintaining the strength of sheet cold-rolled blanks made of deformable aluminum alloys that are not strengthened by heat treatment. Problem. Cold deformation of cold-rolled plates is achieved by recrystallization annealing in hooded furnaces. However, such annealing often does not provide the technological plasticity for defect-free stamping of products and, as a result, has significant rejects. Hooded furnaces are not suitable for improving the deformation of individual billets. In addition, for products with complex configurations that operate in harsh environments, the requirements for rolled aluminum are increased, which is also not possible to realize in open hearth furnaces. These problems can be solved by high-speed continuous parting heat treatment. Goal. The aim is development of a high-speed recrystallization annealing regime for increasing technological plasticity while maintaining the strength of cold-rolled sheet billets from deformable aluminum alloys. Methodology. The object of the study was thin-sheet (1 mm) billets from cold-rolled aluminum alloys AD1, AMts, AMg3. Strip blanks were subjected to high-speed continuous recrystallization annealing using contact heating. The metal was heated at a rate of 5 ºC/c to temperatures from 250 to 400 ºC with an interval of 50 ºC with a holding time of 5 - 15 min at the heating temperature and cooling in air. The quality of the annealing was judged by the nature of the obtained structure and indicators of mechanical properties. The ability to extract metal in different states was evaluated by the Eriksen method. Result. The least energy-consuming modes of continuous high-speed annealing of workpieces from the studied alloys were developed to obtain increased plasticity indicators (while maintaining strength) and improve cold pressure processing in the manufacture of products of complex configuration. Practical value. High-speed recrystallization annealing provides reduction of defects, saving of metal, improvement of productivity in the production of thin-sheet items by the method of cold deformation with deep and complex drawing.

Improvement of Grain Structure of AA6063 Alloy Billet Casting

In this study; it was aimed to develop AA6063 alloy Aluminum alloy billet properties of 203 mm in diameter. For this purpose; metal temperature, casting and liquid metal height at the casting table. After the casting process, the homogenization process was carried out at different times, temperatures and different cooling rates. Microstructure, hardness and tensile tests were carried out on the samples taken from the test billets and parameters were determined for the production of AA6063 alloy billets with a diameter of 203 mm.

Parametric analysis of the self-organization effect in the combined burnishing of holes in aluminum alloy billets

The process of self-organization of machined surfaces during combined burnishing of workpiece holes made of Д1Т aluminum alloy with a tool with a regular microgeometry of the working surface using a metal-cladding lubricant is studied. This treatment provides the wear-free Garkunov—Kragelsky effect during friction. Keywords: burnishing, hole, regular relief, metal-cladding lubricant, wear-free effect, friction. nadezhdachi@yandex.ru, bekaev@list.ru, drsc1@yandex.ru, ld-gim@yandex.ru

Understanding the recrystallization kinetics in aluminium alloy billets with poorly developed cast structure

The paper describes the study of structure evolvement in A0 aluminum and 8011 and 8006 aluminum alloy billets with a low degree of the cast structure working when rolled at 300–500 °C and 3–8 s–1 strain rate. The grain structure was studied by optical microscopy with Axiovert 40 MAT microscope, intermetallic particles analysis was made using JEOL 6390A scanning electron microscope. Grain structure analysis showed that a dendritic structure gradually stretching in the direction of strain is observed in the cast state. Review of the effect of deformation modes and subsequent annealing on the grain structure helped obtain analytic equation to describe recrystallization kinetics. The effect of the Zener-Hollomon parameter value on recrystallization kinetics during subsequent annealing was demonstrated. It was established that at this stage of thermomechanical processing recrystallization kinetics strongly depends both on the Zener-Hollomon parameter and on the amount of strain. The higher content of such impurity elements as silicon and iron gives larger amount of secondary metastable fine particles. This leads to an increase in recrystallization inhibiting force determining recrystallization progress in many respects. Moreover, the number of second phase particles will determine how much the amount of strain affects deformation kinetics. The highest recrystallization rate is observed in pure aluminum, the lowest – in alloy 8006. At low values of the Zener-Hollomon parameter, recrystallization process in this alloy can be fully blocked.This research was funded by the Russian Science Foundation; Project 18-79-10099-П, https://rscf.ru/project/21-79-03041/.

Numerical Studies of Batch and Inline High Shear Melt Conditioning Technology Using Different Rotors

When casting aluminum alloy billets, high shear melt conditioning (HSMC) technology refines the resulting grain size, reduces the number of defects, and improves mechanical properties without the need to add polluting and expensive chemical grain refiners. These resultant improvements spring from the high shear rates that develop in the rotor–stator gap and the stator holes facing the leading edge of the rotor. Despite the growing literature on rotor–stator mixing, it is unclear how the different rotor–stator parameters affect the performance of high shear treatment. To upscale this technology and apply it to processes that involve large melt volumes, an understanding of the performance of the rotor–stator design is crucial. In this paper, we present the results of computational fluid dynamics (CFD) studies of high shear melt conditioning in continuous and batch modes with different rotor designs. These studies build upon our earlier work by studying the effect of rotor variation in a stator design consisting of rows of small apertures at different rotor speeds spanning from 1000 to 10,000 revolutions per minute. While no clear-cut linear pattern emerges for the rotor performance (as a function of the design parameters), the rotor geometry is found to affect the distributive mixing of microparticles, but it is insignificant with regards to their disintegration.

PERFORMANCE EVALUATION OF BLACK SOAP (TOILET SOAP) BLENDED WITH DE-OILED JATROPHA CAKE ADDITIVE AS SOLID LUBRICANT IN DIRECT COLD EXTRUSION OF ALUMINIUM ALLOYS

The use of petro-lubricants in metal forming leads to lamination of oxide on the extrudates due to temperature increase and reaction of the base metal with some elements in the lubricant, hence resulting poor surface quality of the end product. The non-biodegradability of these lubricants also leads to environmental pollution. Although De-oiled Jatropha Caked has been volarised for so many applications, with some oil left in the cake it can still be employed for use in other applications. In this paper a bio-solid lubricant is formulated from Black soap (Toilet soap-vegetable oil-based) as base and De-oiled Jatropha cake as additive. Jatropha seeds were processed to ≤ 0.5 um particles size powder and de-oiled using Soxhlet apparatus. Black soap and de-oiled Jatropha cake was then mixed in ratios: 90:10, 80:20, 70:30, 60:40 and 50:50. Each of these was further mixed with de-ionized lukewarm water in ratio 50:50 by weight to produce solid lubricant blends B1, B2, B3, B4 and B5, respectively. Each of the Black soap-enriched solid lubricant blends were then used to test for coefficient of friction on mirrored surface prepared aluminum specimens using Ball-on-disc Tribometer. The solid lubricant blends were again used to conduct Extrusion tests on Ø25.4 mm by 25.4mm aluminum alloy billets in direct cold extrusion process on a 2000 KN capacity UT CO821 machine. The results showed blend B3 (70:30) recording the minimum coefficient of friction and extrusion force values μ=0.732 and 170.53KN, respectively. These results reveal that enriched solid lubricant B3 (70:30) is most suitable for aluminum alloys extrusion.

Numerical and Experimental Study on the Direct Chill Casting of Large-Scale AA2219 Billets via Annular Coupled Electromagnetic Field.

The internal coupled electromagnetic melt treatment (ICEMT) method is firstly proposed to produce high-quality and large-sized aluminum alloy billets. A three-dimensional model was established to describe the ICEMT process of direct chill casting (DC casting). The effect of ICEMT on the fluid flow patterns and temperature field in the DC casting of ϕ880 mm AA2219 billets is numerically analyzed. Moreover, the mechanisms of the ICEMT process on grain refinement and macrosegregation were discussed. The calculated results indicate that the electromagnetic field appears to be coupled circinate at the cross section of the melt, the fluid flow becomes unstable accompanied by the bias flow, and the temperature profiles are significantly more uniform. An experimental verification was conducted and the results prove that compared with traditional direct chill casting, the microstructures of the AA2219 large-scale billet under the ICEMT process are uniform and fine.

Influence of ultrasound irradiation on transient solidification characteristics in DC casting process: Numerical simulation and experimental verification

It is well known that solidification of molten metals occurs under the influence of transient unsteady phenomena, which are difficult to control in actual casting operation. Examples include buoyancy flows, natural heat convection, repeated remelting and solidification in mushy zone and solid shell at the mold interface. This paper presents the results suggesting that ultrasound waves, irradiated into the hot-top mold offers an attractive way to control the transient phenomena in DC casting of aluminum alloy billets. A novel mathematical model was developed to simulate the DC casting with considering transient melt flow, heat transfer, ultrasound propagation, acoustic streaming and solidification. It was found that ultrasound irradiation alters the solidification behavior of melt and sump evolution especially in the earlier stage of casting, however as the billet length increases, the sump profile becomes almost the same for both the ultrasonic and conventional castings. In this condition, the casting speed becomes the key parameter influencing the sump evolution and mushy zone volume. The results reveal that ultrasound-driven acoustic streaming and turbulent oscillations result in a suppression of buoyancy flow in the sump and lead to an increase of frequency of the melt temperature oscillations at the solidification interface. One of the useful results of these phenomena can be a more frequent repetition of remelting/solidification cycle and improvement of the billet quality, particularly the billet surface morphology. The effect of ultrasound irradiation on the billet morphology was verified experimentally using a pilot DC caster.

Computer Simulation of the Technology for Producing a Stamped Billet for the Piston of an Internal Combustion Engine of an Unmanned Aerial Vehicle

The technological process of hot-die forging billets for the piston of an internal combustion engine (ICE) of an unmanned aerial vehicle (UAV) made of AK4-1 aluminum alloy using the Deform-3D software package has been modeled. The object of simulation is a real ICE piston mounted on a Russian UAV. During modeling, the following parameters are introduced: the temperature of the tooling and the billet is 450°C, the ambient temperature is 20°C, the speed of the punch is taken as 5 mm/s, and the Siebel friction index is 0.4. A rigid plastic medium is chosen as the material model. The number of elements (6000) is assigned so that at least three of them fit in the narrowest section of the part. Thus, using the example of a stamped piston forging, it is shown that, using computer simulation in the Deform-3D program, it is possible to develop processes of hot-die forging of aluminum alloy billet for the manufacture of pistons for UAV ICEs. At the same time, computer modeling allows you to design a tool, evaluate the power parameters of the hot-die forging process, study the nature of the shape of the billet during die forging, and make the necessary adjustments to the virtual technological process that will make it possible to select the most optimal technical solutions when designing a real process. This computer-simulation technique can be extended to other stamped forgings from aluminum alloys.

Computer simulation of the technology for AK4-1 alloy die forging production for an internal combustion engine piston

The process of hot die forging of AK4-1 aluminum alloy billets for the piston of an internal combustion engine (ICE) for an unmanned aerial vehicle (UAV) was simulated using the Deform-3D software package. The object of research was an ICE piston mounted on one of the UAV types of Russian production. Simulation was performed using the following parameters: tooling and billet temperature was 450 °C, ambient temperature was 20 °C, punch speed was 5 mm/s, and Siebel friction index was 0.4. Rigid plastic medium was chosen as a material model. The number of elements (6000) was selected so that at least 3 elements fit in the narrowest section of the part. Thus, as illustrated by the piston die forging, computer simulation in the Deform-3D software makes it possible to develop hot die forging processes for making aluminum alloy billets for UAV ICE pistons. At the same time, computer simulation can be used to evaluate the power parameters of the hot die forging process, study the nature of billet forming in die forging, make necessary adjustments to the virtual process, and develop the design of a die forging tool in order to select the most effective process solutions when designing a real process. The described computer simulation technique can be extended to other aluminum alloy die forgings.

Structure and Properties of Al–0.6wt.%Zr Wire Alloy Manufactured by Direct Drawing of Electromagnetically Cast Wire Rod

The method of electromagnetic casting (EMC) was used to produce the long-length rod billet (with a diameter 12 mm) of aluminum alloy containing 0.6 wt.% Zr, 0.4%Fe, and 0.4%Si. The combination of high cooling rate (≈104 K/s) during alloy solidification and high temperature before casting (≈830 °C) caused zirconium to dissolve almost completely in the aluminum solid solution (Al). Additions of iron and silicon were completed in the uniformly distributed eutectic Al8Fe2Si phase particles with an average size of less than 1 µm. Such fine microstructure of the experimental alloy in as-cast state provides excellent deformability during wire production using direct cold drawing of EMC rod (94% reduction). TEM study of structure evolution in the as-drawn 3 mm wire revealed the onset of Al3Zr (L12) nanoparticle formation at 300 °C and almost-complete decomposition of (Al) at 400 °C. The distribution of Zr-containing nanoparticles is quite homogeneous, with their average size not exceeding 10 nm. Experimental wire alloy had the ultimate tensile strength (UTS) and electrical conductivity (EC) (234 MPa and 55.6 IACS, respectively) meeting the AT2 type specification. At the same time, the maximum heating temperature was much higher (400 versus 230 °C) and meets the AT4 type specification.

Microstructure and Macrosegregation of Ф508 mm 7050 Aluminum Alloy Billet under Internal Electromagnetic Stirring

To obtain fine microstructure and homogeneous distribution of alloying elements in the large-sized billet, the internal electromagnetic stirring as a new electromagnetic stirring method was proposed and utilized for the preparation of Ф508 mm 7050 aluminum alloy billet. The results demonstrate that the internal electromagnetic stirring could refine the microstructure and second phase, and alleviated the macrosegregation significantly. The grain size at the edge, 1/2 radius, and center of the billet decreased to 180 μm, 175 μm, and 185 μm, respectively. Moreover, the relative macrosegregation of Zn, Mg, and Cu at the edge and center decreased to 3.9% and 2.8%, 2.3% and 1.6%, 4.1% and 2.5%, respectively.

Automatically search of a rational cutting mode for milling non-rigid blanks with the specified quality parameters

The work is devoted to the question of lowering the cost of production engineering products by reducing the costs of technological training. The possibility of cutting mode selection based on the quality of the processed parts using the proposed methodology for determining the roughness, elastic deformation of the item in the process of mechanical machining non-rigid parts of machines and technological level of residual stresses. The algorithm search automation rational cutting mode a brute-force attack all possible combinations of milling with calculation mode settings for each of the required quality parameters. Shows his work in appointing cutting mode for accommodative wall milling on aluminum alloy billet D16T.

Validation of phosphor thermometry for industrial surface temperature measurements

Surface temperature measurements are required by the aerospace and automotive industries to guarantee high-quality products and optimize production processes. Accurate and reliable measurement of surface temperature is very challenging in an industrial environment. Surface contact probes are widely used but poorly characterized, while non-contact infrared thermometry is severely hampered by the unknown emissivity of the surface and by problems caused by stray radiation from the background. An alternative approach to the above techniques is phosphor thermometry, used here in a hybrid contact/non-contact approach.In this work, the development of a lifetime-based phosphor thermometer, its application to industrial surface temperature measurement and its validation are reported in a metrologically sound manner. The phosphor thermometer was initially calibrated by contact on a reference calibrator system at the Istituto Nazionale di Ricerca Metrologica to provide SI traceability to the measurements at the industrial level; the system was later validated by exploiting a metal phase-change method. The robustness of the approach against a strong radiative background was also investigated. A comprehensive uncertainty analysis was carried out, resulting in an expanded uncertainty (k = 2) lower than 1.4 °C over the temperature range from the ambient to 450 °C.The phosphor-based thermometer was then tested at industrial manufacturing premises to measure the surface temperature of aluminium alloy billets during the pre-heating phase before forging. The phosphor-based approach was compared with radiation and contact thermometry in both static and dynamic measurement conditions. The experimental results proved that phosphor thermometry, besides being a valid alternative to conventional techniques, may offer better performance in an industrial setting.

Internal electromagnetic stirring method for preparing a large-sized aluminum alloy billet

Abstract The study proposes internal electromagnetic stirring as a new electromagnetic stirring method. The structural features of the internal electromagnetic stirrer and traditional electromagnetic stirrer have been compared. Further, the effects of the internal electromagnetic stirring on the direct chill casting of a large-sized 2219 aluminum alloy billet have been investigated. The results demonstrate that the internal electromagnetic stirring can refine and homogenize the microstructure more significantly than the traditional electromagnetic stirring; grain sizes of 124 – 135 μm and 137 – 157 μm are obtained using the former and latter methods, respectively. Moreover, compared with the traditional electromagnetic stirring, the internal electromagnetic stirring is more efficient.

Prevention of seizure in extrusion of aluminium alloy billet by dies having textured surface

Seizure occurring in extrusion of an aluminium alloy billet was prevented by texturing the die surface. A liquid lubricant is entrapped in micro pockets produced on the textured surface, and is flowed out during extrusion to prevent the lubricant film breakdown. TiCN-based cermet and WC-Co dies having high anti-seizure property were employed, and the dull micro pockets were formed on the die surface by shot peening and polishing processes. The anti-seizure property was evaluated from single extrusion and repeated extrusion of an A5056 aluminium alloy billet using a liquid lubricant containing a sulphur additive. Although the roughness of the textured surface was about one order of magnitude larger than that of the polished surface, the anti-seizure property is considerably higher, whereas the difference in extrusion load between both surfaces was comparatively small. It was found that the TiCN-based cermet die having the textured surface has a high anti-seizure property.

Homogenization and Extrudability of 5056 Aluminum Alloy Billet

Through a series of homogenization and extrusion experiments, the extrusion efficacy of 5056 seamless tubes is improved. Although better extrusion practice was apparent with better homogenization parameters for 5056 alloy, a little over-burning structure and phenomena were found on and in the surface and segregation zone of homogenized billet. The extrudability is worse than theoretical level with no aluminum and magnesium oxide particles on the billet surface. Additional, another quality problem in this study is the segregation zone in 5056 larger billets. The over-heat structure was smoothly flowed into the seamless tube by indirect extrusion, and that makes surface bubbles.

Analysis of single-operation cold forging of a hollow ball from a tubular billet

The article reports the results of an experimental and theoretical study of a single-stage cold forging process. This process was used to produce hollow balls with an outside diameter of 30 mm, with two central openings. The forgings were made from tubular aluminum alloy billets with wall thicknesses of 3 mm and 4 mm. The other dimensions of the billets (outer diameter and height) were varied, always making sure that the volume of the forging remained constant. The results of the study were discussed with a special focus on forming conditions, quality of the forging, potential limitations of the process, and the impact of billet dimensions (also expressed as non-dimensional slenderness ratios) on the conditions of the forming process.

Numerical modeling of annular electromagnetic stirring with intercooling in direct chill casting of 7005 aluminum alloy billet

Uniform direct chill (UDC) casting method was developed by combining annular electromagnetic stirring (A-EMS) with intercooling in direct chill casting. In order to investigate effect of UDC on flow patterns, temperature profiles and solidification during the casting, a numerical model of the UDC casting process was developed and used to simulate the UDC casting process for preparing 7005 aluminum alloy billets. The comparison of the calculated results of UDC casting with normal direct chill (NDC) casting indicated that flow patterns, temperature profiles and the sump depth are modified remarkably by the application of annular electromagnetic stirring and intercooling during the direct chill casting. The sump profile and the temperature history during UDC casing were studied, and the mechanism of the casting process were discussed. The comparisons between the simulations and experimental results suggested that the proposed model provides good agreement for the sump profiles and the temperature history within the billets.

Effect of UDC Casting on Hot Deformation Behavior and Properties of 2A14 Aluminum Alloy

Uniform direct chill (UDC) casting is coupled annular electromagnetic stirring and intercooling, having been utilized for the preparation of large-sized aluminum alloy billet. In this paper, the UDC casting was applied to 2A14 aluminum alloy billets with a diameter of 584 mm. Hot compression tests, cogging and ring rolling procedures were carried out for the billets, respectively. The results show that during the deformation temperature of 420 °C and the strain rate of 0.01 s−1 to 10 s−1, the flow stresses of different positions are higher and more stable in the UDC casting billet than in the normal direct chill (NDC) casting billet. The dislocation glide is the dominant deformation mechanism of 2A14 aluminum alloy. Meanwhile, the UDC casting significantly improves the mechanical properties of the rolled rings in tangential and axial directions compared with the NDC casting.