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The article presents the results of a complex analysis referring to the possibilities of applying different types of construction of forging dies used on a hydraulic hammer Lasco HO-U 160 in order to select the optimal solution in the aspect of obtaining the required dimension-shape accuracy. The analysis involved the use of the numerical simulation software FORGE 3.0 NxT. 12 different variants were analyzed, of both different tool constructions and detail arrangements on the die (in a quadruple and sixfold system). The effect of the forces as well as the way of material flow and degree of the forging tool seat’s filling were verified. The most ergonomic and technologically justified detail arrangement on the die was described. The results of the numerical simulation analyses were presented with the indication of the pros and cons of the particular solutions. The selected solution of the forging tool construction, implemented in a mass production, was especially discussed to verify of obtained FEM results and improvement actual technology.

The study refers to a comprehensive analysis of the occurrence of defects in forgings constituting elements of window fittings, for which, in the process of their production through precision die forging in a six-impression system at elevated temperatures on a hydraulic hammer, we observe bending of the whole forged element and tilting of the stem (a conical element protruding in a plane perpendicular to the main axis of the forging) in the particular forgings. The investigations included analysis of the technology of precision forging on a hydraulic hammer with an energy of 16 kJ, advanced numerical simulations of the process with the use of a calculation package Forge 3.0 NxT, and dynamic tests of mutual displacement of tools performed by means of a high-speed measurement camera. Preliminary analysis of the process showed that, for forgings with a narrowed dimensional and shape tolerance, produced dynamically on a hammer, the key role is played by elastic deformations as well as the construction of the dies and the geometry of the working impressions, and also the changing tribological conditions. For this reason, multi-variant numerical simulations, including two variants of tools (the standard process and the so-called broken perpendicular flash), were carried out, which made it possible to determine the temperature and forging force distribution in the tools as well as the correctness of the deformed forging material’s flow, the filling of the working impressions, and the defects in the forgings. Next, with the use of a high-speed camera, measurements of the relative displacement of the dies were performed, which showed that a proper change in the construction (geometry) of the tools and the use of locks positively affects the minimization of the displacements and thus increases the quality and dimensional and shape precision. The proposed approach using numerical simulations and dynamic measurements of displacements allows for a relatively quick analysis and the introduction of necessary changes in the technology, including modifications of the construction and geometry, in order to minimize the forging defects. That said, the obtained results did not unequivocally point to one specific optimal solution; therefore, the issue of a total elimination of forging defects is still open and constitutes a scientific challenge. And so, further research and verification studies are required to improve the current forging technology and eliminate forging defects in multiple systems in longer operational periods.

The article presents a comprehensive review of key issues and challenges related to enhancing the durability of hot forging tools. It discusses modern strategies aimed at increasing tool life, including modifications to tool materials, heat treatment, surface engineering, tool and die design, die geometry, tribological conditions, and lubrication. The review is based on extensive literature data, including recent publications and the authors’ own research, which has been implemented under industrial conditions at the modern forging facility in Forge Plant “Glinik” (Poland). The study introduces original design and technological solutions, such as an innovative concept for manufacturing forging dies from alloy structural steels with welded impressions, replacing traditional hot-work tool steel dies. It also proposes a zonal hardfacing approach, which involves applying welds with different chemical compositions to specific surface zones of the die impressions, selected according to the dominant wear mechanisms in each zone. General guidelines for selecting hardfacing material compositions are also provided. Additionally, the article presents technological processes for die production and regeneration. The importance and application of computer simulations of forging processes are emphasized, particularly in predicting wear mechanisms and intensity, as well as in optimizing tool and forging geometry.

Rotary press forging (RPF) has been introduced in the last century. Despite its advantages, it produces defects in the forgings such as mushrooming, eccentricity, and twisting. Rotary hammer forging (RHF) is a new process invented by the author to reduce such defects. RHF is considered as a multi-axes compression forging process where the material is subjected to several repeated hammering blows to be deformed incrementally and partially, while the produced deformation zone is swept over the whole area of the workpiece. Previous works showed that the specimen geometry, the inclination angle and the rotational speed affect such defects as mushrooming effect, eccentricity and twisting angle, but they are less severe in RHF than RPF. The present work has studied the effect of the forming degree (FD) on the forgings produced by both RPF and RHF to compare between the two processes. Special set-ups have been used where a die is rotating while either a pressing head or hammering head is used to deform the specimen. Independent variable parameters were chosen such that the specimen geometry H/D = 1, the inclination angle = 4 , the rotational speed N =260 rpm, number of blows per revolution in case of RHF = 1.2. The results showed that FD has its influence on the mushrooming effect, twisting angle, and eccentricity, although they are less in the case of RHF. RHF reduces the defects referred to RPF by 5 to 13% for the mushrooming effect, 0 to 33% for the eccentricity, and 70 to 80% for the twisting angle. Thus, RHF is advantageous than RPF.

Precision forgings represent a critical area of industrial research. However, existing model-based control methods often rely on empirical values to simplify the force conditions of the guide pillars in die forging presses, resulting in insufficient model accuracy throughout the entire forging process and adversely affecting the dimensional quality of precision forgings. To address this issue, this paper develops a novel mechanical model for the guide pillars of die forging presses, which is validated against finite element simulations performed using COMSOL software. The simulation results indicated that the mechanical model exhibited minor errors compared to the finite element analysis result, thereby it is effective to use this physical model to acquire precise control, supporting more precise model-based control of the complete forging process.

The engine main shaft forgings have high requirements for product consistency and reliability, which are difficult to be guaranteed by traditional manual free forging. On the basis of the already-in-place machinery, technical optimization was done in order to realize intelligent forging of the engine main shaft forgings. A rail trailer, holding robot, inspection robot, and expert system were installed as well as other hardware and software. Additionally, the procedure and specifications for robot intelligent free forging were revised. Based on the artificial neural network (ANN) model, an optimization model and a prediction model were created, and the process parameters can be controlled during forging. The verification result shows that the intelligent free forging production line can achieve real-time control of the shaft forging process, and obtain the forgings whose shape, size, microstructure, performance and consistency meet the requirements. With the help of this production line, free forging can be produced more quickly and efficiently, which is crucial for realizing the automation, digitization, and intelligence of shaft forging free forging.

The long shaft forgings in the roll forging forming process and the rigidity of the metal will change due to temperature. When the roller forging clamping device holds the forging piece on one side, the shaft forging piece will be bent due to self-weight, and the height of the other side of the forging piece will be changed, which will affect the operation of forging automation. In this paper, through the statistical analysis of sample data, the relationship between forging temperature and height deviation value is fitted, which solves the problem of how the change in the height of long shaft forgings affects robot handling in the automation process of roll forging. The stability of the forging automation is improved, while the method reduces the investment cost of the production line by using models instead of expensive vision hardware.

This paper provides a review of the methods developed over the years for reducing working forces for the precision metal forming processes. Precision forging normally involves completely, or near completely closed cavity dies with no or minimal draft, making features on the extremities difficult to fill and requiring high loads. Means to minimise load, in order to enhance tool life, or reduce press capacity are crucial to the success of precision forging processes. The main concentration of this study is on design features which can be incorporated in tooling and/or workpiece in order to assist in minimisation of forging load while achieving complete die filling. The load reduction methods are presented using examples mainly of precision gear forging, which is representative of the precision forging of other axisymmetric components with complex peripheral shape. The methods reviewed are divided into the categories of (i) billet design, (ii) tool design and (iii) process design. Their effects on forging load reduction for precision forging, along with the authors’ opinions as to the benefits, drawbacks and applicability of each, are presented.

Flashless forging is classified as a precise metal forming technology. The main advantages of this technology are the reduction of the flash allowance and the shortening of the manufacturing time by eliminating the flash trimming operation. The article presents the process of one-step forging of a stepped shaft made of aluminum with the use of split dies. The process was carried out in cold and hot metal-forming conditions. The forging process was analyzed numerically using the Simufact Forming 15.0 software. The geometrical parameters of the obtained product were analyzed, and the distribution of effective strain, temperature, and the standardized cracking criterion was determined. The process force parameters were also determined. Numerical tests were verified in real conditions with the use of a specially designed device for forging in vertical split dies. Comparison of hot and cold forging in vertical split dies is presented. The comparative analysis results have demonstrated that the hot forging process has more advantages than the cold forging process. The hot forging process ensures higher accuracy of forged parts.

To enhance the forming quality of the forging and minimize the forging cost in the concave radial forging process, this article examines the influence of process parameters (radial reduction ∆ h , rotation angle β , friction coefficient μ ) on the forging process through numerical simulation. A multi-objective optimization method is employed to balance the objective functions (strain homogeneity E , forging load F ). First, sample points for different combinations of process parameters were obtained using a central composite experimental design. Then, a mathematical model between the process parameters and the objective function was established using the response surface method, which underwent variance analysis and sensitivity analysis. Finally, the optimal process parameter combination was determined based on the NSGA-II algorithm and satisfaction function. The optimization results were verified by finite element simulations. The optimized process combination: ∆ h  = 0.25 mm, β  = 21.68°, μ  = 0.05. The corresponding E and F are 0.241367 and 577.029, respectively. Compared with the initial process, the standard deviation of the overall strain was reduced by 14.25%, and the forging load was reduced by 1.76%. The results indicate that the quality of the forgings was significantly improved while the forging cost was reduced to some extent.