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The article describes the main loads affecting shaped backups of the combined process unit of continuous casting and deformation during billet production. The importance of determining the temperature fields and thermoelastic stresses in shaped backups with collars is provided during the formation of several billets, at slab compression, as well as during idling water cooling of backups. The authors describe strength and thermophysical properties of steel from which the backups are made. Geometry of backups with collars used for obtaining billets of three different shapes in one pass is shown. Initial data of the temperature field calculation are given for backups with collars of the combined unit. Temperature boundary conditions are considered for the temperature field calculation of backups with collars. Boundary conditions determining temperature of such backups are described and the values of the heat flow and effective heat transfer coefficient are given. The calculation results of temperature fields are performed in four sections and are given for typical lines and points located on the contact surface of backups with collars and in contact layer at 5-mm depth from the working surface. The sizes of the finite element grid, which is used for the temperature field calculation of backups with collars, are provided. The temperature field of backups with collars is determined based on the solution regarding the unsteady thermal conductivity equation corresponding to initial and boundary conditions. When obtaining billets of three shapes in one pass at the unit of combined continuous casting and deformation, values and regularities of temperature distribution in the bases and tops of the middle and extreme edges of the shaped backups are presented during slab compression and at idle. © 2020, Allerton Press, Inc.

Lightweight multi-material components are of great importance for the transport industry. Not only the component’s weight can be decreased, but also its local properties can be adapted to different loading profiles. Tailored Forming is a novel concept for producing multi-material components. By using a joining process, the creation of a bond between different materials takes place in the first step of the process chain. In the subsequent steps, multi-material workpieces are processed in their joined state while maintaining or improving the joint strength. This study focuses on steel-aluminium joints, which were created by friction welding and further processed by induction heating and impact extrusion. A counter pressure superposition mechanism was implemented in the extrusion tooling to control the stress state during plastic deformation. Flow behaviours of steel and aluminium are largely different at a given temperature, which necessitates a near step-function temperature distribution in the hybrid billet to obtain matching flow stresses. An inductive heating strategy was developed which led to a temperature gradient in the billets before extrusion. Extruded billets were analysed by destructive testing methods and metallography. The bond could be maintained after extrusion when counter pressure superposition was used; but no improvement could be obtained. Without counter force superposition, however, cracks were observed in the joining interface and the joint strength decreased. This paper discusses the aforementioned findings in the current process design and makes suggestions on how the involved processes should be reconfigured to improve the joint strength.

Particulate nanocomposites with the base of ZA27 alloy were synthesized using an innovative route, which includes mechanical milling and compocasting. Scrap from the matrix alloy and ceramic nanoreinforcements were mechanically milled using the ball-milling technique, which led to the formation of composite microparticles. The use of these particles in the compocasting process provided better wettability of ceramic nanoreinforcements in the semi-solid metal matrix, which resulted in a relatively good dispersion of the nanoreinforcements in nanocomposite castings. The presence of nanoreinforcements led to the grain refinement in the matrix of nanocomposites. The mechanical properties of the synthesized nanocomposites are improved and compared with the properties of the metal matrix. The observed increase in the hardness of nanocomposites with Al2O3 nanoreinforcements (20–30 nm) was 6.5% to 10.8%, while the yield strength of these nanocomposites has increased by 12.2% to 23.2%. The hardness and compressive yield strength of the nanocomposites with Al2O3 nanoparticles (100 nm) increased by 1.7% to 8.0% and 2.3% to 8.3%, respectively. The increase in hardness of the nanocomposites with SiC nanoparticles (50 nm) was 11.5% to 20.6%, while the increase in the yield strength was 15.6% to 24.5%. The greatest contribution to the overall strengthening in the synthesized nanocomposites is the result of increased dislocation density due to the difference in coefficients of thermal expansion for the matrix alloy and nanoreinforcements.

The problem statement and boundary conditions for calculation of axial thermoelastic stresses in backups with unit collars of combined continuous casting and deformation are provided for production of three steel billets. The calculation scheme for determination of thermoelastic stresses in backups with collars in a known temperature field was stated using ANSYS software. The calculation results of thermoelastic stresses in shaped dies were performed in four sections of a backup with collars. In each section, calculation results are given for four typical lines and seven points. Values of axial thermoelastic stresses for seven typical points of each section are given for the contact surface of a backup with collars and the contact layer at a depth of 5 mm from the contact surface. The stress state of a shaped backup in the middle of depression between the middle collars was determined and the distribution regularities of axial and equivalent stresses over the thickness, length and width of a backup were established during slab compression and at idle. The calculation results of thermoelastic stresses in the top of the middle collar of a shaped backup on the contact surface and in the contact layer during slab compression and at idle are presented. Graphs of thermoelastic stress distribution along the line passing through the top of a collar are given, which show the zones of compressive and tensile thermoelastic stresses during slab compression and at idle. The character of the stress state in the base of extreme collar was determined for production of three steel billets in the unit of combined process of continuous casting and deformation. © 2021, Allerton Press, Inc.

Introducing systems capable of profound reduction in a casting and rolling module improves the product quality, on account of the intense working of large continuous-cast slabs over the whole cross section and the production of uniform fine-grain structure of the metal, and also increases the cross section of continuous- cast billet. Analysis of the formation of nonmetallic inclusions and segregation in the axial zone of the thick rolled sheet is followed by analysis of the nonuniform deformation over the slag height in the reduction of large continuous-cast slabs at the 5000 mill at OAO Magnitogorskii Metallurgicheskii Kombinat. The structure of a cyclic-deformation system for preliminary deformation of large continuous-cast slabs is described, and its capabilities are explored. Hammers for preliminary deformation of large continuous-cast slabs are considered. Experimental data are presented for the deformation of continuous-cast steel 45 and 12Kh18N10T steel billet. The structure of the continuous-cast billet is assessed in the course of reduction on the cyclic-deformation system. The basic parameters of the system for preliminary deformation of large continuous- cast slabs are determined. The capabilities of the cyclic-deformation system are outlined in terms of increase in sheet quality. On that basis, the use of the cyclic-deformation system in the continuous-casting line for preliminary reduction of large continuous-cast slabs is recommended: it permits matching of the speed of continuous-casting and cyclic-deformation processes; and ensures 45–90% reduction in a single pass so as to obtain well-worked cast structure over the whole slab cross section. When using the cyclic-deformation system in the continuous-casting line, the continuous-cast slabs are reduced by means of the heat of the cast metal, thereby greatly reducing the energy consumption in billet production. The cyclic-deformation system may be used with thick-sheet and broad-strip mills for preliminary single-pass reduction of the hot slab, with improvement in sheet quality and reduction in the number of passes in the mills. © 2017, Allerton Press, Inc.

The objective of this presentation is to show and explain why semisolid slurries can fill thin sections at seemingly unlimited flow velocity the suitability of SSM parts with very thin sections is a characteristic of the process that is often overlooked by the industry. This characteristic provides a unique opportunity for new advanced applications of the process, not possible by other existing metal-mold casting methods. © (2015) Trans Tech Publications, Switzerland. 217-218 159 165 159-165

A thermal deformation treatment (TDT) method is developed and implemented during production of industrial batches of chromium bronze bars, according to which aging is performed after intermediate billet drawing to a prefinishing diameter, then finishing drawing of an aged billet follows to a final diameter with a drawing factor of 1.10-1.25. Batches of bars treated by this method correspond entirely to all standard document specifications with respect to hardness and longitudinal curvature, and bars have the required marketable condition with smooth, defect-free, shiny surface typical for cold-drawn products. © 2013 Springer Science+Business Media New York.

When using continuous-cast billet in pipe rolling, it is expedient to roll the billet prior to broaching, so as to improve the structure and properties of the steel. To that end, a three-high screw-rolling mill for billet reduction has been installed at the TPA-80 pipe-rolling unit at OAO Sinarskii Trubnyi Zavod. Introduction of the new process was associated with increase in the rejection rate on account of indentations in the pipe. These indentations may be attributed to the depression formed at the rear of the billet in reduction and the subsequent formation of metallic semicircles on broaching; the semicircles break away and enter the deformation zone. The sources of the indentations on the rolled pipe are investigated. The broaching of the billet on a screw rolling mill is mathematically simulated. Recommendations are made with a view to reducing the surface defects on pipe produced by the TPA-80 unit with a reduction mill. © 2013 Allerton Press, Inc.

The structural and phase constituents of metal samples cut from hollow tube billets hardened by fine tungsten and silicon carbides and formed by centrifugal casting are studied. © 2012 Pleiades Publishing, Ltd.

The feasibility of using the equal channel angular extrusion (ECAE) process for the breakdown of cast structures in commercial purity aluminium has been investigated. Billets of an as-cast coarse grained Al (99.7% pure) were subjected to ECAE at 500�C using a die that imparts an equivalent plastic strain of 0.67 per pass. Multiple extrusion passes were performed using two different processing routes: Route I in which the billet orientation was kept constant from pass to pass, and Route II in which the billet was rotated by 180� about its longitudinal axis from one pass to the next resulting alternately in shear in planes oriented at 120� to each other. Processing by Route I through five passes produced elongated grains showing evidence of dynamic recovery. Processing by Route II through five passes however produced largely equiaxed grains with a dynamically recovered substructure due to the intervention of static recrystallization during the reheating to extrusion temperature between passes. Both processing routes produced a dynamically recovered structure with equiaxed subgrains approximately 6?m in size. Sharp deformation textures were not obtained. The relevance of this technique to industrial processing is discussed. ? 2001 Elsevier Science B.V. All rights reserved.

The quality and durability of metallic materials is of considerable importance in many branches of industry, in particular, in metallurgy, engineering, and construction. This article gives the results of studying the effect of strengthening solid particles on structural heterogeneity, hardness, chemical composition and wear resistance of billets, prepared by centrifugal casting. © 2011 Springer Science+Business Media, Inc.

Thixocasting requires manufacturing of billets with non-dendritic microstructure. Aluminum alloy A356 billets were produced by rheocasting in a mould placed inside a linear electromagnetic stirrer. Subsequent heat treatment was used to produce a transition from rosette to globular microstructure. The current and the duration of stirring were explored as control parameters. Simultaneous induction heating of the billet during stirring was quantified using experimentally determined thermal profiles. The effect of processing parameters on the dendrite fragmentation was discussed. Corresponding computational modeling of the process was performed using phase-field modeling of alloy solidification in order to gain insight into the process of morphological changes of a solid during this process. A non-isothermal alloy solidification model was used for simulations. The morphological evolution under such imposed thermal cycles was simulated and compared with experimentally determined one. Suitable scaling using the thermosolutal diffusion distances was used to overcome computational difficulties in quantitative comparison at system scale. The results were interpreted in the light of existing theories of microstructure refinement and globularisation. � 2010 The Nonferrous Metals Society of China.

Al-Li-SiCp composites were fabricated by a simple and cost effective stir casting technique. A compound billet technique has been developed to overcome the problems encountered during hot extrusion of these composites. After successful fabrication hardness measurement and room temperature compressive test were carried out on 8090 Al and its composites reinforced with 8, 12 and 18 vol.% SiC particles in as extruded and peak aged conditions. The addition of SiC increases the hardness. 0.2% proof stress and compressive strength of Al-Li-8%SiC and Al-Li-12%SiC composites are higher than the unreinforced alloy. In case of the Al-Li-18%SiC composite, the 0.2% proof stress and compressive strength were higher than the unreinforced alloy but lower than those of Al-Li-8%SiC and Al-Li-12%SiC composites. This is attributed to clustering of particles and poor interfacial bonding. � 2008 Elsevier B.V. All rights reserved.

Due to the distinct rheology of semisolid slurries the process has well established advantages over competing near-net-shape manufacturing technologies. Despite the obvious advantages of the process its adoption by the casting industry, however, has been slow. This is primarily due to lack of confidence of how these slurries flow in die cavities. The added cost associated with the specially prepared slurry has also affected the process commercial success. Nevertheless despite these problems attention to the semi-solid metal process has indeed increased over the years. The main focus of this review is the modeling of semisolid slurries. The objective here is to present an overview of relevant aspects of modeling by focusing on the physics of the slurry and by stressing consistent mathematical and analysis methods to determine the material constants. 141-143 17 23 17-23

With increasing demand for steels for drawing at higher speeds, the quality, in terms of internal defects and macro structural features (central porosity, equiaxed zone, etc.), of billets has become of paramount importance. By optimizing the Electro Magnetic Stirrer (EMS) parameters viz., EMS current and frequency the severity of defects, area of columnar zone as well as central porosity, in continuously cast billet can be effectively minimized. The result would be an increase in equiaxed zone area and improved internal soundness. In the present work attempts have been made to determine the best combination of EMS current as well as frequency to ensure good internal soundness of billets. The EMS current and frequency were changed to different values in the range of 300A to 350 A and 4Hz to 6Hz respectively. Corresponding billet samples were collected for macro structural evaluation. The samples were scanned using an immersion ultrasonic C-scanner to get images of samples. Macro structural features revealed by ultrasonic C-Scan were analysed for determining the best combination of EMS parameters. It was observed that in the range under trial, % equiaxed zone and % central void area were not affected significantly by varying the EMS parameters.