Precision Forging Research Articles

Application of Numerical Simulations for a Multi-Variant Analysis of the Construction of Tools Assigned for Hot Precision Forging of Small Size Forgings in Multiple Systems

Application of Numerical Simulations for a Multi-Variant Analysis of the Construction of Tools Assigned for Hot Precision Forging of Small Size Forgings in Multiple Systems

Improvement of the Technology of Precision Forging of Connecting Rod-Type Forgings in a Multiple System, in the Aspect of the Possibilities of Process Robotization by Means of Numerical Modeling.

The study refers to the application of numerical modeling for the improvement of the currently realized precision forging technology performed on a hammer to produce connecting rod forgings in a triple system through the development of an additional rolling pass to be used before the roughing operation as well as preparation of the charge to be held by the robot's grippers in order to implement future process robotization. The studies included an analysis of the present forging technology together with the dimension-shape requirements for the forgings, which constituted the basis for the construction and development of a thermo-mechanical numerical model as well as the design of the tool construction with the consideration of the additional rolling pass with the use of the calculation package Forge 3.0 NxT. The following stage of research was the realization of multi-variant numerical simulations of the newly developed forging process with the consideration of robotization, as a result of which the following were obtained: proper filling of the tool impressions (including the roller's impression) by the deformed material, the temperature distributions for the forging and the tools as well as plastic deformations (considering the thermally activated phenomena), changes in the grain size as well as the forging force and energy courses. The obtained results were verified under industrial conditions and correlated with respect to the forgings obtained in the technology applied so far. The achieved results of technological tests confirmed that the changes introduced into the tool construction and the preform geometry reduced the diameter, and thus also the volume, of the charge as well as provided a possibility of implementing robotization and automatization of the forging process in the future. The obtained results showed that the introduction of an additional rolling blank resulted in a reduction in forging forces and energy by 30% while reducing the hammer blow by one. Attempts to implement robotization into the process were successful and did not adversely affect the geometry or quality of forgings, increasing production efficiency.

Research on Corporate Income Tax Planning-taking Precision Forging Technology Company as an Example

Research on Corporate Income Tax Planning-taking Precision Forging Technology Company as an Example

Automated defect detection in precision forging ultrasonic images based on deep learning

Ultrasonic testing is a widely used non-destructive testing technique for precision forgings. However, assessing defects in ultrasonic B-scan images can be prone to errors, misses, and inefficiencies due to human judgment. To address these challenges, we propose a method based on deep learning to automate the evaluation of such images. We started by creating a dataset comprising 8000 images, each measuring 224 × 224 pixels. These images were cropped from ultrasonic B-scan images of 7 specimens, each featuring different sizes and locations of holes and crack defects. We then used state-of-the-art deep learning models to benchmark the dataset and identified YOLOv5s as the best-performing baseline model for our study. To address the challenges of deploying deep learning models and the issue of small defects being easily confused with the background in ultrasonic B-scan images, we made lightweight improvements to the deep learning model. Additionally, we enhanced the quality of data labels through data cleaning. Our experiments show that our method achieved a precision of 97.8%, a recall of 98.1%, mAP@0.5 of 99.0%, and mAP@.5:.95 of 67.6%, with a frames per second (FPS) of 74.5. Furthermore, the number of model parameters was reduced by 43.2%, while maintaining high detection accuracy. Overall, our proposed method offers a significant improvement over the original model, making it a more reliable and efficient tool for automated defect assessment in ultrasonic B-scan images.

Titanium Alloy Artillery Barrel and Radial Precision Forging Technology Discussion

The application of titanium alloy barrel in artillery weapon system can effectively reduce the weight of artillery, which is significant to enhance its mobility, precision strike capability and battlefield survivability. Based on the review of relevant literature, the development and application of titanium alloy and titanium alloy barrel and barrel forging process are summarized, which lays the technical foundation for the research of titanium alloy barrel radial precision forging technology. At the same time, the current problems of titanium alloy artillery barrel radial precision forging are proposed, and the corresponding pre-solution is given, which has important research value and practical significance to effectively improve the comprehensive performance of titanium alloy barrel. It has an important research value and practical significance to effectively improve the comprehensive performance of titanium alloy barrel.

Influence of the grade of hot work tool steels and its microstructural features on the durability of punches used in the closed die precision forging of valve forgings made of nickel-chrome steel

The work concerns research related to the assessment of the influence of the impact of the steel grade used for forging punches in terms of the durability of tools used in the precision forging process in closed dies of a chrome-nickel steel valve forging. The tests were carried out on post-service punches, showed microstructural differences in the intensity of carbide precipitations banging. Two of them were made of a materials showing carbide banding (W360 after ESR; 1.2365), which achieved average durability at the level of: 2400 and 1200 forgings. The other two were without clear carbide banding (Unimax after ESR; 1.2344). They also had much lower durability at the level of: 700 and 200 forgings. Tests of post-service punches were carried out in order to assess the mechanism of their destruction. They were supplemented with hardness measurements. The dominating mechanism of their wear was the loss of properties of the surface layer. The decrease in hardness and plastic deformation of the material resulted in increase of the punches wear rate. As part of laboratory tests, scratch-tests and abrasion wear tests on a “ball on disc” tribotester at elevated temperatures (above 400 °C, i.e. contact temperature: tool-forging) were carried out. The obtained test results showed that punches made of materials with distinct banding, compared to materials with evenly spaced carbide clusters, are characterized by better resistance to the destructive mechanisms prevailing in hot forging processes.

Problems of the process of manufacturing precision forgings in multiple systems on a hot hydraulic hammer

The article presents the results of a complex analysis referring to a periodical occurrence of forging defects in the form of twisting of pin-type elements (perpendicular to the main forging axis) as well as lack of total filling of these areas on the forgings in the process of hot precision forging on a hammer. The studies included: an analysis of the forging technology, advanced numerical simulations of the process and dynamic tests of the mutual shifting of the tools with the use of a high-speed measurement camera. The hot precision forging process was realized on a double operation hydraulic hammer with the maximal energy of 16 kJ, as a result of which, a so-called leaf is formed in the dies in two operations, which has 6 relatively small forgings (the mass of one is about 40 g), characterizing in a narrowed scope of dimension-shape tolerance (0.1–0.2 mm and 0.5–1°). The performed preliminary process analysis showed that, for this type of forgings made in a dynamic manner on a hammer, the key role is played by elastic deformations as well as the construction of the dies (application of guide locks) and the impression geometry. Additionally, during the forging process, in the case of pin-type elements (shape of a truncated cone with the convergence of 1°), their twisting was observed as well as small underfills caused by “closed volumes”, connected with the non-vaporized lubricant and the formation of air pockets. The mentioned problems relating to this process significantly affect the quality and precision of the forgings and cause defects. For this reason, based on the results of the conducted tests and analyses, a different approach to the design of dies was applied than in standard hammer forging technologies. It was introduced the necessary changes in the technology as well as modify the construction and geometry of the tools (in the lower die a negative slope was applied) in order to eliminate joggle and twisting of the forging elements, which disqualify such items.

Development of Preliminary Precision Forging Technology and Concept for Tools Used to Reforge 60E1A6 Profile Needle Rails with the Use of Numerical and Physical Modeling

This study examines the possibilities of applying numerical and physical modeling to the elaboration of technology and design of tools used in the hot forging of needle rails for railroad turnouts. First, a numerical model of a three-stage process for forging a needle from lead was built in order to develop a proper geometry of the tools' working impressions for physical modeling. Based on preliminary results of the force parameters, a decision was made to verify the numerical modeling at 1:4 scale due to forging force values as well as agreement of the numerical and physical modeling results, which was confirmed by the similar courses of forging forces and a comparison of the 3D scan image of the forged lead rail with the CAD model obtained from FEM. The final stage of our research was modeling an industrial forging process in order to determine the preliminary assumptions of this newly developed method of precision forging using a hydraulic press as well as preparing tools to reforge a needle rail from the target material, i.e., 350HT steel with a 60E1A6 profile to the 60E1 profile used in railroad turnouts.

Precise Shrink Fitting Design of the High Strength Gear Mold for the Precision Forging of Noncircular Spur Bevel Gears

Shrink fitting of forging mold (SFFM) is an effective method for improving mold strength, extending the mold's service life and reducing the manufacturing cost of forging mold. However, due to the asymmetric geometry and complex stress distribution, the precise design of SFFM for the precision forging of noncircular bevel gears is very difficult. In this paper, a new precise design method of SFFM for the precision forging of noncircular bevel gears is proposed, which mainly includes the following five parts. First, a new design method for the mold parting surface-the curved surface parting method-is proposed to design the forging mold of noncircular spur bevel gears. Then, new dimension design methods for the gear mold and shrink rings based on the uniform shrinkage force are proposed. Third, a new design method for the inhomogeneous interference value between shrink rings and the gear mold is developed to provide a precise, uniform shrinkage force. After that, a strength correction method for the shrink-fitted gear mold is proposed to ensure the gear mold and shrink rings have sufficient strength both in the assembly process of the shrink-fitted gear mold and precision in the forging process of noncircular spur bevel gears. Ultimately, finite element simulations and verification experiments are performed to verify the proposed precise design method of SFFM for the precision forging of noncircular bevel gears. The precise design method of SFFM proposed in this paper is not only applicable to the precise design of the high-strength gear mold for noncircular bevel gears, but can also provide a valid reference for the precise design of the high-strength mold for other complicated asymmetric parts.

COMPARISON OF FORGING LOAD, MATERIAL FLOW AND PRESSURE DISTRIBUTION OF THE UNI-DIRECTIONAL, BI- DIRECTIONAL AND TWO-STEP FORGING PROCESSES

Because of high productivity, closer dimensional tolerances, and minimal material waste precision forging (net or near net shape) processes have been used for manufacturing automobile components. The primary disadvantage of precision forging is the encountered higher tool stresses due to applied higher forging loads. Thus, forging load reduction is a higher priority in precision forging in terms of energy consumption and cost because higher loads required higher investment and higher energy consumption. Forging load is affected by several parameters such as temperature, material flow, the geometry of the billet, and punch movement. In this study, forging load, material flow, and normal pressure distribution in the forged part were investigated considering uni-directional, bi-directional, and two-step forging processes. FEM simulations were performed by using a solid cylindrical billet. To perform FEM simulations, the finite element analysis package (DEFORM 2D) was used. Also, experimental studies of the FEM models were performed. For bi-directional and step-forging experimental studies, a double-acting servo press was used because the movement of the top and bottom punch can be controlled accurately. Then the results of FEM and experimental studies were compared with each other. The results of the FEM simulations and experimental studies show two-step forging offers lower forging load and energy consumption whereas the uni-directional closed die forging process needs higher load and energy consumption

Effect of process parameters on forming quality of hollow axle blank with rotary piercing

At present, hollow axles are mostly manufactured by precision forging and then deep processing, which has long technological process and high cost. In order to realize the integrated forming of hollow axles with short process and low cost piercing and skew rolling, a method of piercing billet by two-roll skew rolling is proposed in this paper, and the finite element model of the forming process is established by using SimufactForming software. The effects of roll feed angle, roll speed and plug advance on the wall thickness uniformity of piercing tube billet are explored, and the process parameters with the best wall thickness uniformity are obtained. It lays a technical foundation for the blank guarantee and the realization of the integrated forming process of hollow axle.

Prediction of high-temperature flow stress of HMn64–8–5–1.5 manganese brass alloy based on modified Zerilli-Armstrong, Arrhenius and GWO-BPNN model

An accurate constitutive model is essential for designing the process of hot precision forging and numerical simulation. Based on the isothermal compression tests of as-extruded HMn64–8–5–15 manganese brass alloy at the deformation temperature of 873–1073 K and strain rate of 001–10 s−1, the effect of the friction and deformation temperature rise on the flow stress during the hot compression process was analyzed, and the flow stress curves were corrected. Three constitutive models based on the modified Zerilli-Armstrong, Arrhenius, and a back-propagation neural network (BPNN) optimized by the grey wolf optimization (GWO) algorithm (GWO-BPNN) models were established to describe the high-temperature flow stress of this alloy. Meanwhile, the prediction ability of the three models was evaluated by the calculated values of mean absolute percentage error (MAPE) and root mean square error (RMSE). The values of MAPE for the modified Zerilli-Armstrong, Arrhenius, and GWO-BPNN models were computed to be, 3139 %, 2448 % and 1265 %, and the values of RMSE were calculated to be 1804, 1482 and 0467 MPa, respectively. The GWO-BPNN model was with the greatest prediction ability for the flow stress among these models. The GWO algorithm was introduced to optimize the initial weights and thresholds of the BPNN model, and it has good prediction accuracy and better stability. It can better describe the high-temperature flow behavior of HMn64–8–5–15 alloy.

UDDEHOLM UNIMAX

Abstract Uddeholm Unimax is a high-hardness chromium-molybdenum-vanadium alloy hot-work tool steel that provides high wear resistance at elevated temperatures. It performs very well in precision forging and hot stamping. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on heat treating and machining. Filing Code: TS-826. Producer or source: Uddeholms AB.

A simplified formula for determination of relative pressure in the precision forging of spur gears

In this study, the relative forging pressures of spur gears were evaluated. The precision forging of spur gears was analyzed by using the upper bound method considering corner filling and bulging effect. Numerical and experimental studies were performed to investigate the effects of various parameters, such as the number of teeth, modules, facewidth, bore diameter, and friction factor on the relative forging pressure of spur gears. The results were compared with the previous studies and a simplified formula was suggested to predict the relative pressure of precision forging of spur gears. The predicted relative forging pressures obtained by the suggested formula are shown much closer to the experimental results for the complete filling of the die cavity.

Precision Micromassive Forming of Microgears at Different Temperatures

The precision micromassive forming of microgears was performed at different temperatures with the combination of wire electron discharge machining and precision forging. Microgear molds with 0.1-, 0.2-, and 0.4-mm modules and 12 teeth were fabricated with SODICK, AP250Ls, WEDM software, respectively, at a dimensional tolerance of ≤ 2.5 μm and surface roughness below 280 nm. The precision forging of microgears was investigated on T2 copper with the combination of simulation and experiment. The middle part was filled first, followed by the upper end and, finally, the bottom end. It was quite difficult to form microgears that meet the quality requirements at normal temperature. However, such a problem does not exist at 773 K, and the forming force required was only 36.4% as large as that at room temperature. Microgears formed with the high-temperature forging method exhibited high precision, and the dimensional tolerance was reduced from -38.8 μm of room temperature forging to + 0.9 μm, and the surface roughness was about 300 nm.

Development and Application of High-Temperature Constitutive Model of HNi55-7-4-2 Alloy

The constitutive model is still not available for theoretical and engineering analysis of HNi55-7-4-2 alloy, which is a new type of wear-resistant brass alloy widely applied to car synchronizer rings and ship condenser tubes etc. In the current investigation, a friction-corrected stress-strain curve was obtained through a hot-compression test to develop the high-temperature constitutive model of HNi55-7-4-2 alloy based on the Hansel–Spittel model. By comparing predicted flow stress and a simulated force-stroke curve with experimental results, the proposed constitutive model was verified. The developed constitutive model was applied to numerically simulate the hot precision forging of a synchronizer ring. The simulation results based on two process plans on material flow and forging defects were validated by process experiment. The Hansel–Spittel high-temperature constitutive model proposed in this work enables the theoretical and engineering analysis of HNi55-7-4-2 alloy.

Research and application of precision forging forming process for flat thin flash of automobile disc steering knuckle

The steering knuckle is the important safety part of commercial vehicle, the structure is more complex as the performance improved. In this paper, a kind of disc-type steering knuckle with complexity up to level S4 is studied, and a precision forging process is proposed to change the traditional horizontal open pre-forging and large flash final forging into semi-closed flat thin flash pre-forging and semi-closed flat thin flash final forging. Based on the analysis of mechanism and effect of the classical forming theory on the flat thin flash, the equivalent stress, equivalent strain and temperature distribution field as well as the force formation curve and deformation law are obtained by means of thermal-mechanical coupled finite element simulation analysis, and the correctness of the process scheme is verified. The precision forging of steering knuckle has been successfully developed on the program controlled hammer and CNC electric screw press, the results are consistent with the simulation results. The material utilization rate of the new process is 88%, which is 16% higher than that of the traditional process, with better quality and stronger bearing capacity. In recent years, the company has built four automatic production lines with CNC electric screw press as main equipment, with robot operation and online detection of hot forging, it has realized mass production of flat thin flash precision forging of A161 disc-type knuckle series product.

Closed-die Forging Technology and Numerical Simulation of Aluminum Alloy Connecting Rod

Abstract In order to improve quality and reveal the law of precision forging, closed-die forging technology is used in this paper to conduct a numerical analysis of the forming process of aluminum alloy connecting rod by the DEFORM software. Forming effects under different loading modes were acquired, and forming process, blank flow characteristics, stress-strain distribution and load-stroke curve characteristics were analyzed. Study results indicate that the forming effect under the loading mode featuring first movement of lateral punch and then movement of upper and lower punches is good with high quality forge piece and no defect, the closed-die forging technology of aluminum alloy connecting rod is reasonable and feasible. Under a certain deformation velocity and deformation mode, aluminum alloy connecting rod forming load firstly reduces and then increases, the forming load is in direct proportion to deformation velocity. When the forming process is finished, forming load reaches 130T, it accords with the production practice. The study results provide a certain reference for guiding the formulation of closed-die forging production technology of aluminum alloy connecting rods.

Research on the Shunting Precision Forging of Ribbed Plate Gear Blank Based on DEFORM-3D Finite Element Analysis Under the Framework of New Engineering

In order to solve these problems in the precision forging, such as non-saturate, folding, high energy consumption and low material utilization, a certain type motor vehicle of ribbed plate gear blank was selected as the main focus. Based on the principle of shunting and the law of minimum damping, the finite element model of shunting precision forging was established by using finite element numerical simulation software DEFORM-3D, and the temperature field, equivalent strain field and workpiece were analyzed in depth. The results show that the end faces of ribbed plate are flat and there are no folding defects at the bottom. The influence of damage and forming load on forming process and quality provide theoretical basis and technical support for shortening R&D cycle and optimizing reasonable process parameters in actual production.

Some Manifestations of Antioxidation Coating for Hot Precision Forging Gears

A high temperature protective coating was prepared onto the surface of 20CrMnTi steel by brushing technique, and the heated billet was subjected to hot forging. Compared with an uncoated sample, the effect of coating on high-temperature oxidation behavior of steel was investigated by scanning electron microscopy-energy dispersive spectroscopy and X-ray diffraction. Before hot forging, an oxide layer of 153 μm was formed on the surface of the uncoated sample; however, no oxide layer was formed on the surface of the coated sample. After hot forging, the thickness of scale on the surface of uncoated gear forging is 89 μm while the thickness of coating on the surface of coated gear forging is 39 μm. It is concluded that such a coating material not only enhances the dimensional accuracy but also improves the surface quality of the gear.