Die Forging Process Research Articles

Durability of Forging Tools Used in the Hot Closed Die Forging Process—A Review

The article presents the classification of the wear mechanisms of forging tools. The durability of dies can be enhanced through a variety of methods, including the selection of appropriate hot working tool steel, the application of effective heat treatment, the utilization of advanced surface engineering techniques, and the incorporation of lubricating and cooling agents. Two popular methods of tool regeneration, such as re-profiling and laser regeneration, are presented. The issue of numerical wear prediction based on the Archard model, the correlation of this model with experimental results, low-cycle fatigue (HTLCF), and an alternative method based on artificial neural networks are discussed. The paper aims to present currently known wear mechanisms and the methods of increasing and predicting tool durability.

Hybrid manufacturing process combining laser powder-bed fusion and forging for fabricating Ti–5Al–5V–5Mo–3Cr–1Zr alloy with exceptional and isotropic mechanical properties

The metal additive manufacturing (AM) technology offers a unique advantage for production of complex and unconventional parts. However, the thermal history during the AM process often leads to anisotropy in the mechanical properties and inherent porosity of the deposits, which limits their performance compared to traditional forgings. To overcome these limitations, laser powder bed fusion (LPBF) technology was employed to produce single-step die-forging preforms. This innovative approach used coarse powder with a wide distribution of particle sizes to create a variety of molten pool structures, preventing the growth of columnar β grains in AM Ti–5Al–5V–5Mo–3Cr–1Zr (Ti-55531) alloys. The subsequent die-forging process eliminated inherent defects and regulated grains to be near-equiaxed, significantly improving the mechanical properties and reducing anisotropy. With proper post-heat treatment, the strength-ductility trade-off of the Ti-55531 alloy was adjusted to meet standards. This unconventional process route produced parts with isotropic and excellent mechanical properties, overcoming the defects and anisotropic properties of AM parts. This supplement to the traditional manufacturing process of high-performance titanium alloy parts holds great promise for future applications.

Analysis and Improvement of an Industrial Process of Hot Die Forging of an Elongated Forging Tipped with a Joggle with the Use of Numerical Simulation Results

Analysis and Improvement of an Industrial Process of Hot Die Forging of an Elongated Forging Tipped with a Joggle with the Use of Numerical Simulation Results

Modeling of the Closure of Metallurgical Defects in the Magnesium Alloy Die Forging Process.

The article discusses the impact of hot forging elongation operations on the closure of metallurgical discontinuities such as middle porosity in selected magnesium alloys (AZ91) depending on the shape of the input used. Numerical modeling was carried out using the Forge®NxT 2.1 program based on the finite element method and laboratory modeling in order to bring about the closure of defects of metallurgical origin in deformed forging ingots. On the basis of the conducted research, optimal values of the main technological parameters of forging and appropriate groups of anvils to be used in individual stages of forging were proposed in order to eliminate metallurgical defects.

Effect of Cooling Rate and Nb on the Microstructure and Hardness Variation in Microalloying Medium-Carbon Non-Quenched and Tempered Steel Simulated in a Die Forging Process

Effect of Cooling Rate and Nb on the Microstructure and Hardness Variation in Microalloying Medium-Carbon Non-Quenched and Tempered Steel Simulated in a Die Forging Process

Simulation Research on Die Forging Process Optimization of the FDN Type Anti-vibration Hammer Head in UHV Transmission Lines

Traditional anti-vibration hammer heads are mainly manufactured by gravity casting technology, which has many internal defects and limited mechanical properties, which cannot meet the technical requirements for higher-strength anti-vibration hammers in the construction of UHV transmission lines. Die forging is an advanced material forming process for producing low defect and high strength anti-vibration hammer. However, the process parameters should be strictly controlled to realize the complete filling of forgings and reduce the damage of forgings and dies.In this paper, the die forging process of the FDN type anti-vibration hammer head was simulated by using Deform-3D software platform, and the optimal forging process parameters were proposed as follows: the diameter of the blank is 65mm, the length of the blank is 184mm, the pressing speed of the upper die is 200mm/s, and the preheating temperature range of the blank is 800?∼1000?. The mechanical properties of the anti-vibration hammer after process optimization met the requirements of the corresponding strength grade products.

Characterization of the Interface between Aluminum and Iron in Co-Extruded Semi-Finished Products.

Within the framework of the Collaborative Research Center 1153, we investigated novel process chains for the production of bulk components with different metals as joining partners. In the present study, the co-extrusion of coaxially reinforced hollow profiles was employed to manufacture semi-finished products for a subsequent die-forging process, which was then used for the manufacture of hybrid bearing bushings. The hybrid hollow profiles, made of the aluminum alloy EN AW-6082 paired with either the case-hardening steel 20MnCr5, the stainless steel X5CrNi18-10, or the rolling bearing steel 100Cr6, were produced by Lateral Angular Co-Extrusion. Push-out tests on hybrid hollow sections over the entire sample cross-section showed shear strengths of 44 MPa ± 8 MPa (100Cr6) up to 63 MPa ± 5 MPa (X5CrNi18-10). In particular, the influence of force and form closure on the joint zone could be determined using specimen segments tested in shear compression. Locally, shear strengths of up to 131 MPa (X5CrNi18-10) were demonstrated in the shear compression test. From these samples, lamellae for microstructural analysis were prepared with a Focused Ion Beam. Detailed analyses showed that for all material combinations, a material bond in the form of an ultra-thin intermetallic phase seam with a thickness of up to 50 nm could be established.

Study on the Recognition of Malposition and Location of High-Temperature Forgings in Robotised Die Forging Process Based on Machine Vision

Recognition of malposition and location of high-temperature forgings play a critical role in the realisation of robotised die forging, which is an ongoing trend in intelligent manufacturing. This study is aimed at the robotised die forging of the scraper beam of armoured face conveyor, which is the only transporting equipment used in the coal mine workface. Firstly, a novel process to recognise the malposition and location of high-temperature forgings using two monocular cameras, one placed horizontally and another vertically, is proposed. Secondly, a novel image preprocessing algorithm combining the algorithms of grey linear transformation, exponential transformation, and median filtering is proposed. After processing the high-temperature forging image using the proposed image preprocessing algorithm, the grey difference between the target region and background region of the processed image is highly increased. This is conducive to the subsequent image segmentation and contour extraction processes conducted in the forging region. Thirdly, after the comparison and analysis of the three commonly used image segmentation methods, including edge detection, threshold segmentation, and region growing methods, it is discovered that the region growing method is suitable for image segmentation of high-temperature forgings. Fourthly, a two-way modified and blob analysis based forging location algorithm is proposed to reduce the location error caused by the axial and radial asymmetric flash during the forging process. Finally, the proposed algorithms are validated by experiments and the location recognition error of the proposed location algorithm is only 0.86059 mm. This study provide technical support for the realisation of robotised die forging.

FINITE ELEMENT SIMULATION OF Ti-6Al-4V BILLET ON OPEN DIE FORGING PROCESS UNDER DIFFERENT TEMPERATURES USING DEFORM-3D

ABSTRACT This paper explains the methodology of developing an open die-forging model using Deform-3D software to simulate the hot forging process on Ti-6Al-4V billet used in aerospace applications. Three-dimensional finite element model of an open die-forging model was designed in the Deform-3D software. To complete the simulation run, it comprises three modules, namely, pre-processing, simulation and post-processing. During pre-processing module, as per open die-forging process setup requirement two dies and one billet has been created using the standard data of forging. Suitable temperature conditions of Ti-6Al-4V material varying from 500°C to 1000°C are applied to billet. After the simulation had run with 100 steps, during post-processing step effective stress and strain, total velocity and displacement, final temperature was recorded. From results, it was observed that with increasing forging temperatures at 500°C, 750°C and 1000°C of hot Ti-6Al-4V billet – effective stress and strain were decreased, total displacement and velocity were decreased and the final temperature was increased. Deform-3D software will be used for finite element simulation to predict the metal flow behaviour effectively, during the forging process.

Case Study of the Effect of Precoating on the Decarburization of the Surface Layer of Forged Parts during the Hot Die Forging Process.

This paper aims to evaluate the effect of pre-coating of forged parts on decarburization in the die forging process. The studies consisted of three stages. In the first instance, different coatings were tested under laboratory conditions by heating steel samples to the temperature of 1200 °C for over five minutes to model the preheating conditions of the induction. Next, testing continued in a commercial forging stand where we tested the effects of different coatings on the rods decarburization during the induction heating process, usually performed before forging. Once completed testing, the measurements and observations of the decarbonized layer were made. The third stage involved analysis of the decarburization of the forged parts after forging. The forged parts were made using precoating of pre-forging elements; pieces cut off a metal rod. Based on tests results, the possibility of using this solution in the technique of industrial hot forging was evaluated. The results of laboratory tests have confirmed that lubrication of metal pieces is sufficient, as well as proved it to be effective in reducing decarburization of the surface layer. Research works conducted in an induction heater showed differences in decarburization depending on a substance and concentration of lubricants that were used. These differences become more apparent when observing the surface layer of the forged parts. Results indicate that decarburization may be reduced to a minimum when we use Bonderite product in a concentration of 66% and 50%. Another lubricant, Berulit 913, may also be used. However, due to burning graphite in high temperatures, reduction of decarburization goes only as far as half of the thickness of the decarbonized layer. Condursal has no significant effect; nevertheless, it protects over the induction heating stage.

Numerical Simulation and Experimental Verification of Disc Cutter Rings in Die Forging Process

In order to study the forming law of the disc cutter ring in the independently researched die, the finite element model (FEM) of disc cutter ring for die forging has been established and the die forging process has been simulated by the plastic forming software. The metal flow field, temperature field, stress and strain field of the filling process were obtained by simulation. The exerted force of the die was also simulated and analyzed; thus, the die forging process was optimized. Based on the designed process parameters and simulation results, the experimental study on die forging forming of cutter ring was carried out. The comparison shows that the numerical simulation results are in good agreement with the experimental results, which proves that the die forging model of disc cutter ring in this paper is feasible.

Advanced disk-forging process in producing heavy defect-free disk using counteracting dies

During the conventional disk-forging, the upper die repeatedly compresses materials on the flat stationary base. As the strain distributions of the forged disk are non-uniform owing to friction and uneven temperature distribution, more uniform deformation within the entire volume is desirable to obtain sound disk free from defects. This study proposes an advanced disk-forging process in the production of a defect-free heavy disk using counteracting dies. An industry-applicable disk-manufacturing process using a conventional single die-forging process and a proposed counteracting die were characterized and compared based on variations in geometries with successive forging steps. Variations in stress, equivalent strain, and temperature were obtained through three-dimensional finite element simulations using FORGE™ software, during the disk-forging processes of cylindrical preforms. Comparison of the simulation results indicated that the proposed forging process using counteracting dies was highly effective in producing sound disks having uniform microstructure without process-induced defects. The shop-floor production was performed to validate the proposed process, and the feasibility of the process was demonstrated based on the forged disk qualities that were assessed by non-destructive examination and mechanical testing. The test data showed that the defect-free disk with uniform mechanical properties was successfully produced through the proposed forging process using counteracting dies.

High Nb–TiAl Intermetallic Blades Fabricated by Isothermal Die Forging Process at Low Temperature

In this study, the isothermal die forging process of high Nb–TiAl (Ti-44Al-8Nb-0.2W-0.2B-Y, at.%) alloy blades was simulated using the ABAQUS V6.11 software and the blades were fabricated successfully. The influence of a low forging temperature (lower than 1000 °C) and strain rate on the distributions of effective strain and stress were analyzed. The results indicate that the effective strain exhibits negative temperature sensitivity and positive strain rate sensitivity. The stress exponent (n = 3.02) and the apparent activation energy (Q = 293.381 kJ/mol) of the present alloy suggests that this as-forged high Nb–TiAl alloy exhibits good deformability at low temperatures. With the reduction in strain rate and the increase in forging temperature, the effective stress decreases. Finally, high-quality high Nb–TiAl alloy blades were fabricated using an isothermal die forging technology at a rate of 0.01 mm/s and temperature of 950 °C, chosen on the basis of the simulations results. Scanning electron microscopy (SEM) and electron back scatter diffraction (EBSD) results indicated that the center of the TiAl alloy blade possessed a duplex microstructure, consisting of remnant lamellar colonies and recrystallized γ/B2 grains. The refined α2 laths showed a typical forging flow line feature in the edge position, whereas the γ laths had broken down and recrystallized.

Energy-Saving Hot Open Die Forging Process of Heavy Steel Forgings on an Industrial Hydraulic Forging Press

The study deals with the energy-saving process of hot open die elongation forging of heavy steel forgings on an 80 MN industrial hydraulic forging press. Three innovative energy-saving power supply solutions useful for industrial hydraulic forging presses were analyzsed. The energy-saving power supply of hydraulic forging presses consists in reducing electricity consumption by the electric motor driving the pumps, reducing the noise emitted by pumps and reducing leaks in hydraulic piston cylinders. The predicted forging force as a function of heavy steel forging heights for various deformation temperatures and strain rates was determined. A simulation model of the 80 MN hydraulic forging press is presented, which is useful for determining the time-varying parameters during the forging process. An energy-saving control for the hydraulic forging press based on the forging process parameters’ prediction has been developed. Real-time model predictive control (MPC) was developed based on multiple inputs multiple outputs (MIMO), and global predictive control (GPC). The GPC has been implemented in the control system of an 80 MN industrial hydraulic forging press. The main advantage of this control system is the repeatability of the forging process and minimization of the size deviation of heavy large steel forgings

Design and manufacture of a customised temporomandibular prosthesis

In this work, design, manufacture and surgical success of a personalised temporomandibular prosthesis is featured. A fused deposition modelling technique and Die forging process constitute the methodology used in a patient who had an amputation in the upper third branch of the mandible, without considering the joint capsule. The implant was designed using a processed resection image of a computational tomography and using the methodology of Ozkaya and Nordin. The jaw operating conditions were simulated by the finite element method (FEM). The main considered factors were the morphological geometry of the patient, implant fixation in the first third of the branch, implant fixation on the chin, dental post for placement of the teeth, and the form of the sub-lingual fossa weight optimisation. Special consideration was to preserve the patients facial aesthetics.

Analysis of Void Closure during Open Die Forging Process of Large Size Steel Ingots

Large size forged ingots, made of high strength steel, are widely used in aerospace, transport and energy applications. The presence of internal voids in the as-cast ingot may significantly affect the mechanical properties of final products. Thus, such internal defects must be eliminated during first steps of the open die forging process. In this paper, the effect of in-billet void positioning on void closure throughout the ingot breakdown process and specifically the upsetting step in a large ingot size steel is quantitatively investigated. The developed Hansel-Spittel material model for new high strength steel is used in this study. The ingot forging process (3D simulation) was simulated with Forge NxT 1.0® according to existing industrial data. A degree of closure of ten virtual existing voids was evaluated using a semi-analytical void closure model. It is found that the upsetting process is most effective for void closure in core regions and central upper billet including certain areas within the dead metal zone (DMZ). The volumetric strain rate is determined and two types of inertial effects are observed. The dependence of void closure on accumulated equivalent deformation is calculated and discussed in relation to void in-billet locations. The original combination of information from both relative void closure and the volumetric strain rate provides a way to optimize the forging process in terms of void elimination.

Theoretical study on Cold Open Die Forging Process Optimization for Multipass Workability

Cold Workability limits strength enhancement of austenitic materials through cold deformation. The intrinsic workability is the material characteristic whereas state-of-stress workability is governed by nature of applied stress, strain rate and geometry of deformation zone. For Cold Open Die Forging (CODF), multipass workability is essential. In this work, FEM tool FORGE-3 is used to optimize CODF on hydraulic press by analysis of stress-strain profiles and use of Latham-Cockroft damage criterion. Study recommends optimized process parameters, die combinations and pass-schedules.

Mitigation of Barreling Defect in Open Die Forging Process

Mitigation of Barreling Defect in Open Die Forging Process

The prediction of the evolution of grain size of land-gear forging during the die-forging process

The land-gear forgings are the most important structure parts, made of high strength steel 300M. Because of the bad service environment, the microstructure and performance of the part are very strict requirements. In this article the evolution of grain size during the die-forging process is predicted, the volume fraction of dynamic recrystallization, grain refinement and development of grain size in-homogeneity, and the affection of billet shape on the grain size distribution are analyzed. The simulated results show that the grain size differences on the different billet positions are very large at the deformation beginning. But in final forging stage, the difference of the average grain size is smaller. At some center zones of the part the maximum difference of grain size is bigger than 100 μm.

Variable gutter technique as a novel method to reduce waste material in closed die-forging process

Advanced forging simulation codes leads die designer toward more efficient methods in waste material reduction. In this paper, an approach has been presented to reduce waste material by controlling material flow with variable gutter. Initially, an algorithm is offered for decision making. A control criterion (δ) has been suggested in order to determine the new modified gutter thickness and width. A new formula has been offered to calculate the new dimensions of gutter width and thickness base on (δ) criterion in each step. To evaluate the effectiveness of the proposed criterion and formula a set of Finite volume and finite element simulations has been done on different forging parts. Then a “T shape” part has been chosen as a case study to investigate the effect of variable gutter width method and variable gutter thickness method separately. The FVM and FEM simulation results for variable thickness and width show a waste material reduction of 12% and 14%, respectively. Finally an experimental test has been setup to verify the simulation result of variable gutter thickness method. The simulation and experimental results have a good agreement.