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Mg-3Sn-2Ca (TX32) alloy has good creep resistance but limited workability. Minor amounts of Al and Si have been added to TX32 for improving its hot workability. The processing map for the TX32-0.4Al-0.4Si alloy exhibited two workability domains in the temperature and strain rate ranges: (1) 310-415°C/0.0003-0.003 s and (2) 430-500°C/0.003-3 s. The alloy exhibited flow instability at temperatures < 350°C at strain rates > 0.01 s. The alloy has been forged to produce a cup shape component to validate these findings of processing map. Finite-element (FE) simulation has been performed for obtaining the local variations of strain and strain rate within the forging. The microstructures of the forged components under the optimal domain conditions revealed dynamically recrystallized grains, and those forged in the flow instability regime have fractured and exhibited flow localization bands and cracks. The experimental loadstroke curves correlated well with those obtained by FE simulation. [ABSTRACT FROM AUTHOR]

Roll-forging process is widely used to fabricate the automobile front axle beams. The reasonable selection of the process parameters is significant to ensure the quality and improve the property of the automobile front axle beam owing to the complexity and importance of the preliminary roll-forging process. This paper developed a 3D Finite element (FE) model of the preliminary roll-forging process of the AISI-1045 automobile front axle beam under the Deform-3D platform. A corresponding experiment is subsequently conducted. Good agreement between the experimental and simulative results validates the employed model. Based on this dependable FE model, the influences of initial temperature of billet T, rotational speed of rolls n and friction factor m on the geometric dimension, temperature inhomogeneity, deformation inhomogeneity, and roll-forging load are investigated comprehensively. The results can provide reliable guidelines for the selection of process parameters. [ABSTRACT FROM AUTHOR]

In this paper, the influence of flow stress models on FEM simulation results is discussed; the flow stress of AISI 5140 steel at different T, ε and ε in the temperature of warm-hot forging is measured by a uniaxial compression experiment with a thermomechannical simulator. The experimental results show that flow stress is very complex within the temperature range of warm-hot forging; and the traditional interpolation method adopted in FEM simulation on the basis of cold or hot flow stress models is not scientific. To improve FEM simulation precision, a flow stress mathematic model should be calibrated by experiment. Finally, the calibrated flow stress model of AISI 5140 steel is applied in the FEM simulation of the warmhot forging process of the splined shaft of an automobile. Comparison between the results of FEM simulation and the warm-hot forging experiment indicates that the flow stress model calibrated by experiment is scientific and effective. [ABSTRACT FROM AUTHOR]

This article presents an efficient pseudo-inverse approach for the damage prediction in cold forging process simulation. Pseudo-inverse approach combines the advantages of the fast inverse approach and accurate incremental approaches. Some intermediate configurations are created geometrically and corrected mechanically to well describe the deformation path. The formulation of an axi-symmetrical element based on pseudo-inverse approach is presented. A strain-based damage model is introduced in the flow theory of plasticity. A direct scalar integration algorithm of plasticity-damage is developed, leading to a fast and robust algorithm for large strain increments. The cold forging processes of two axi-symmetrical parts are simulated to validate pseudo-inverse approach by the incremental approach ABAQUS/Explicit. Pseudo-inverse approach gives very good results, but uses much less CPU time. [ABSTRACT FROM PUBLISHER]

In forging process, geometric design of initial billet and tools is very important. Traditionally, engineers use their knowledge and experience to design and optimize the geometric model of forging process by using trial-and-error methods. Such methods are time consuming and cost expensive. It is therefore interesting to design an automatic tools builder based on optimization methodology coupled with virtual finite element simulations, thus helping engineers to improve products and reduce cost. In this article we describe a meta-model based multi-objective optimization methodology for forging process designed to build the theoric Pareto optimal front of the mechanical problem. We go through a four-step process: building parametric computer-aided design geometry model, simulating the forging process according to the DOE, fitting meta-models, and optimizing the process by using an advanced algorithm. Two different meta-models, including polynomial and kriging methods, are constructed, based on the simulation values for different responses. Then optimization algorithms NBI-NLPQLP and NSGA-II are applied to find the optimum solutions based on each different meta-model. In order to drive this procedure automatically we use ModeFRONTIER® software. Using this environment, several macro commands are used to connect the geometry modelling (made with CATIA V5™) and numerical simulation process. As an industrial example, a two-step forging of an aeronautic component shows the efficiency of the proposed methodology. That shows contributions of research in dealing with optimization design of die geometry taking into account technological interactions related to the process and the ductile damage inside the deformed part. A set of solutions selected in particular points of the optimal Pareto front are also presented and analysed. [ABSTRACT FROM PUBLISHER]

By using fast calculation models, the equivalent strain, temperature, and average austenitic grain size in the center of an ingot can be determined. When used in an online process monitor by coupling with a measuring system, these models are fast enough to visualize the current state of an ingot during forging. Based on a model forging process, the use of the program is demonstrated. Comparing results from metallography of the forged billet with the calculated grain size, a good agreement could be achieved (deviation of 6-24%). Even before the forging process, the presented automatic pass schedule optimization can be applied. Through this, a process could be optimized concerning a high homogeneous equivalent strain and a low number of strokes. As result of the optimization, an increasing grain size and temperature could be observed. Thus it could be useful to change other process parameters, like lowering the furnace temperature. [ABSTRACT FROM AUTHOR]

Porosity is one of the most important quality criteria of spray-formed materials in the as-sprayed condition. Typically, spray-formed sheets have a porous rim close to the substrate and depending on the spray conditions cold or hot porosity may also be present in the core of the deposit. This porosity has to be removed or minimized to make further processing steps such as rolling, forging or extrusion possible. In this paper, the influence of both substrate temperature and deposit surface temperature on porosity in spray-formed sheets is studied. For this purpose spray forming experiments (sheet size 1000 mm × 250 mm) were carried out using three different materials: aluminium-bronze, tin-bronze and a nitriding steel. For the copper-base alloys preheated steel-substrates with different temperatures were moved through a scanning spray cone. In the case of steel a ceramic substrate at room temperature was used. In addition to the variation of the substrate temperature, the gas to metal mass flow ratio (GMR) was varied to achieve different deposit surface temperatures. During the run the surface temperature in the deposition zone was measured using a scanning, multi-wavelength pyrometer. Samples of the deposits were polished and rasterized by light microscopy. The local porosity was characterized by digital image analysis. The influence of the substrate temperature and the GMR on the porosity in the vicinity of the substrate is evaluated and discussed in detail. The impact of the deposit surface temperature on the porosity was analyzed and is discussed as well. It was found that the deposit surface temperature has a strong impact on porosity for spray-formed sheets. Finally, experimental results were used to develop a new approach to predict the porosity in spray-formed sheets. The results clearly show the dependence on material properties. This approach can be used to identify process parameters to generate high density sheets in the future. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to investigate the degree of improvement in mechanical properties of aluminum alloy (AA6063) after processing with equal channel angular extrusion (ECAE) using four environmentally benign lubricants. Design/methodology/approach – Aluminum (Al) 6063 bar was annealed at 350°C for 1 hour, machined and cut to billets measuring 14 × 14 × 44 mm3. These specimens for extrusions were machined to the specified dimension to a visibly good finish. The billets were extruded through ECAE die of 14 × 14 mm2 channel cross-section area; the channel angle was 120°; and the angle of the outer arc of the channels was 30°. The punch and container used for the experiment were made of tool steel alloy AISI D2, and were chromium-coated and polished. Four lubricants such as palm, olive, coconut and groundnut oils were used in this study. Findings – The yield, ultimate tensile strengths (UTS) and the ductility of the material ECAEed with palm oil as lubricant, which gave the least extrusion pressure, produces the maximum yield, UTS and ductility, followed by groundnut oil and coconut oil, while olive oil gave the least yield strength, (UTS) and ductility. However, palm oil and olive oil have better load reduction than other lubricants. Furthermore, from the hardness results, though scattered, all of the points at the tensile strained side of the extrudate lie within a reasonably narrow band, suggesting a high degree of homogeneity and greater hardness value within the rod than the compressive side after being ECAEed. Originality/value – It is shown in the paper that all the lubricants tested greatly enhanced mechanical properties of Al 6063 and can effectively replace the petroleum-based lubricants used in forging operations. [ABSTRACT FROM AUTHOR]

In compound-cast-forging of hybrid aluminum parts the positive characteristics of casting and forging processes as well as the different materials are combined. This makes it possible to produce components with complex geometries and different local characteristics. Component areas with high complexity (e. g. with an undercut) are cast, areas that are exposed to high mechanical stresses, are forged. In the conducted investigations a preformed, massive formed semi-finished part out of a wrought aluminum alloy was joined with a die-cast aluminum alloy by casting and forming from the casting temperature in one cast-forging process. The results of the studies show a good joining quality of cast-forged components made of different aluminum alloys. [ABSTRACT FROM AUTHOR]

Japanese blades are culturally interesting objects both from the stylistic point of view and because of their fantastic performance. In this work, we present new results, using a non-invasive approach, concerning these peculiar artefacts. Five Japanese swords pertaining to Koto (987–1596) and Shinto (1596–1781) periods have been analysed through white beam and energy resolved neutron-imaging techniques. The experiments have been performed at the ICON beam line, operating at the spallation neutron source SINQ, Paul Scherrer Institut in Switzerland. The reconstruction of projection data into neutron tomographic slices or volumes allowed us to identify some peculiar characteristics, related to the forging methods that were used by the different schools and traditions in Japan. [ABSTRACT FROM AUTHOR]

During industrial forging of hot metallic shells, it is necessary to regularly measure the dimensions of the parts, especially the inner and outer diameters and the thickness of the walls. A forging sequence lasts 2 h or more during which the diameter of the shell is regularly measured in order to decide when to stop the forging process. For better working conditions, for the safety of the blacksmiths, and for a faster and more accurate measurement, we have developed a novel system based on two commercially available time of flight laser scanners for the measurement of the diameters of hot cylindrical metallic shells during the forging process. The advantages of using laser scanners are that they can be placed very far from the hot shell, more than 15 m, while at the same time giving an accurate point cloud from which three-dimensional views of the shell can be reconstructed and diameter measurements done. Moreover, more accurate measurement is achieved in less time with the laser system than with the conventional method using a large ruler. The system has been successfully used to measure the diameters of hot cylindrical metallic shells. [ABSTRACT FROM AUTHOR]

Preform design is an important aspect of the research and development of the forging processes, which plays a key role in improving product quality, such as improving material filling capacity and reducing forming loads. In industry, preforms are generally designed by the iterative trial-and-error approach. This approach, however, leads not only to the increase of tool cost but also to prolonged production time. On the basis of the minimum energy principle and the minimum resistance law, a new approach by means of 3D electrostatic field simulation and geometric transformation is proposed in this paper to design the preform shape. Two axisymmetric (a disk and a blind-hole) forgings and a long-axis part are used to demonstrate this method, and finite element package DEFORM 3D is used to simulate the forming process for the purpose of verifying the validity and effectiveness of this approach. [ABSTRACT FROM AUTHOR]

The article deals with mechanical properties of forgings used for special technology in cannon barrels production. The forgings are treated by elctroslag remelting technology (ESR) to enhance its plastic properties and yield point. Described experiments are focused on mechanical properties and metallurgical quality (microstructure) of steels from which are the forgings made. The article includes microstructure photographs and description of inclusions located in examined steels. Experimental results compare forgings treated by ESR and next ones without ESR. [ABSTRACT FROM AUTHOR]

The article presents a study on the use of numerical systems in precision forging. It states that the ANSYS® element software with Ansys Parametric Design Language (APDL) and user programmable features (UPF) was used to observe the micro structural developments, such as grain growth and micro structural transformations. Results reveal that a good correlation to the measurements on metallographic specimens was exhibited on the grain sizes of the computed recrystallised microstructure.

The article presents a study which aims to produce strategies of comprehensive process design and improve machines and tooling technologies for precision forging. It mentions that in the sub-projects B1 Process design for precision forging and B2 Innovative machines and tooling technology for precision forging, the process design and tooling configuration were completed. The study indicates that an elaborated knowledge on the material specific heat balance is required in precise tool design.

Squeeze casting is a hybrid metal forming process combining features of both casting and forging in one operation. This paper reports a research in which an attempt was made to prepare solid cylindrical components of LM24 aluminum alloy through squeeze casting. The primary objective was to investigate the effect of process parameters on the mechanical properties exhibited by the castings produced though squeeze casting process. A set of trials were conducted based on parameters settings suggested in Taguchi’s offline quality control concept. The experimental results indicate that the squeeze pressure and the die-preheating temperature were the parameters making significant contribution toward improvement in mechanical properties of squeeze cast LM24 aluminum alloy. [ABSTRACT FROM AUTHOR]

In this work, a comprehensive study of radial forging process is presented through 2-D axisymmetric and 3-D finite element simulations while considering internal tube profile. The tube used in this investigation has four internal helical grooves along its length. The material is modeled with the elastic-plastic behavior, and sliding-sticking friction model is utilized to model the die-workpiece and mandrel-workpiece contacts. The numerical results in the 2-D case are compared with available experimental data. Residual stresses in the forged product, stress concentration around the grooves, pressure distribution on the hammers and mandrel and maximum forging load are studied. The effects of process parameters such as workpiece and die geometries, percentage of deformation, and workpiece motions on residual stresses and applied pressures on the hammers and mandrel are investigated. The results provide a valuable insight into the parameters affecting radially forged products and provide a useful tool for better design of this process. [ABSTRACT FROM AUTHOR]

In order to improve the severe service conditions and balance the needs between the better cavity filling and longer die life of traditional closed die forgings, a new flash land named by resistance wall, which integrated the advantages of closed and open die, was introduced into knuckle hot extrusion dies. The fractional factorial design, , was employed to evaluate main effects of the structural parameters on the cavity filling, the maximum forming load and wear depth in bar fillet area, which was simulated by finite element method. Effects of six experimental factors: wall height, clearance, inclination, root fillet, flash thickness and bridge width were studied and optimised. Based on the results, a sort table about main effects was obtained and validated by production trials. [ABSTRACT FROM AUTHOR]

Highly (00l) oriented Ca3Co4O9-based ceramics were fabricated by spark plasma sintering combined with a dynamic forging process. The grain orientation is effective in lowering the electrical resistivity and enhancing the thermoelectric power factor but with little influence on the Seebeck coefficient. A metallic-to-semiconducting transition temperature can be observed and the activation energy is almost independent of the La-doping. All of the Ca3Co4O9-based ceramic samples exhibit large thermoelectric power, and the figure of merit for La-doped Ca3Co4O9 sample can reach 0.26 at 975 K, which can be a promising candidate of p-type material for high-temperature thermoelectric application. [ABSTRACT FROM AUTHOR]

The author reflects on the Leibniz University Hanover's collaborative research centre (CRC) 489, which develops and analyzes a process chain from forging technology for production precision forged high performance components. He remarks that CRC 489 considers the process option for precision forging, allowing the recovery of technical and economic advantages. The author suggests consideration of individual processes in dealing with manufacturing precision-forged high performance components.