Ring Forgings Research Articles

Research the Dimensional Accuracy of C45 Steel Ring Forgings Produced by Radial Rolling.

The rolling process of rings is a commonly used method for producing annular forgings. There are two primary types of this process: radial-axial rolling and radial rolling. This article presents the research results regarding the latter, in which obtaining a product with the assumed dimensions constitutes a major problem. In industrial practice, the process parameters are based on the experience of technologists and/or by trial and error. This is why the authors considered it justified to undertake the research aimed at determining the influence of the main process parameters, that is, preform temperature and tool speed, on the shape and dimensions of the cross-section, which determine the internal and external diameters of the rolled ring. The research was based on numerical simulations and experimental studies. The results obtained proved that the higher the feed speed of the main roll, the greater the change in the cross-sectional height during rolling, and the smaller the cross-sectional deformation (the so-called fishtail). Nevertheless, a higher preform temperature reduces the final height of the ring and reduces cross-section deformation. On the basis of the obtained test results, guidelines for the process design were postulated, considering the influence of temperature and speed parameters on the final dimensions of the forging and the dimensions of the preform.

Research on point cloud simplification algorithm for ring forgings based on joint entropy evaluation

There are numerous redundant points in the point cloud model of ring forgings obtained by 3D laser scanner. How to remove the redundant points while keeping the model characteristics unchanged is a critical issue. This paper proposes a point cloud simplification algorithm based on the joint entropy evaluation theory. Firstly, the K-D tree is used to search for the K-neighbors of the sampled points. Secondly, a surface is fitted to the spatial neighborhood of the sampled points using the least squares method. The curvature operator of the sampled points is derived on the fitted surface using Riemannian geometry theory. After that, an energy operator is defined by using the normal vectors and distances of the sampled points and their neighborhood points. The joint entropy values of all points in the model are determined based on the probability distributions of these two operators in the local neighborhood. Finally, the data points are sorted by entropy value. Data points with high entropy values are put into the data set U1. Data points with low entropy values are clustered through the K-Means algorithm of swarm optimization. The redundant points outside the cluster centers are removed, and the cluster centers are put into the data set U2. The final simplification results are obtained by integrating data sets U1 and U2. The experimental results show that the point cloud simplification algorithm proposed in this paper is effective and feasible.

Dimension measurement method of ring forgings based on laser scanning and multiple regression filtering algorithm

In order to detect the radial is characterized and the isolated points that deviate from the target point cloud are removed using statistical section dimensions of ring parts in the forging process, we present a new method that processes laser scanning data of the outer radial section profile of ring forgings. Based on regression analysis and point cloud filtering, a multiple regression filtering algorithm is proposed to process the point cloud data for the measurement of the outer diameter of ring forgings. First, the laser scanned point cloud data filtering methods. The outlier clusters are then removed using regression analysis and processed by Gaussian regression filtering algorithms to obtain point cloud data with good circularity characteristics. Next, the Least Squares principle is used to fit a circle to the processed data to obtain information on the external diameter of the ring forgings to be measured. Finally, the feasibility of the method is verified by measuring the outer dimensions of the elliptical ring forgings in the experiment and performing error analysis.

Numerical Simulation and Experiment of Stress Relief and Processing Deformation of 2219 Aluminum Alloy Ring

Large aluminum alloy ring forgings are the core components of heavy-duty rocket fuel storage tanks, and the large residual stress inside the rings leads to poor shape accuracy of large thin-walled parts. The initial stress of the 2219 aluminum alloy ring blank was tested using the drilling method, and the creep constitutive coefficient of the 2219 aluminum alloy was determined through stress relaxation tests. The numerical simulation processes of thermal stress relief (TSR), vibration stress relief (VSR), and thermal–vibration stress relief (TVSR) were compared and established. Through the correlation analysis between the actual measurement results of residual stress and the simulation results, it can be seen that the strong correlation in three directions at each measurement point accounts for over 37.5%, and the moderate correlation accounts for over 62.5%. This indicates that the numerical simulation model of 2219 aluminum alloy ring containing initial residual stress can accurately reflect the size and distribution of residual stress inside the actual ring. The simulation results show that the derived constitutive model can describe the stress relaxation process of TVSR by combining a single thermal time effect stress relaxation constitutive theory with a VSR plastic deformation material model. The simulation models established above were used to calculate the residual stress homogenization ability of three types of aging. The results showed that VSR, TSR, and TVSR can homogenize and reduce the residual stress field inside the ring, improve the distribution of residual stress inside the ring, and have a better overall homogenization ability of TVSR. The VSR control has a certain effect on reducing and homogenizing residual stress, but compared with TSR and TVSR, the reduction and homogenization ability of residual stress control is limited. The homogenization control effect TVSR > TSR > VSR, and the maximum equivalent stress homogenization rates of VSR, TSR, and TVSR are 52.8%, 80.6%, and 82.2%, respectively. Then, numerical simulation technology was used to study how the initial residual stress in the blank causes the deformation of the ring during the thin-walled machining process. The roundness error theory of the minimum containment area method was applied to evaluate the deformation degree during the thin-walled numerical machining process, and the TVSR method was used for stress regulation. The deformation law of the thin-walled machining of the ring under different aging parameters was studied.

Production Scheduling Optimization during Thermoforming of Ring Forgings Based on Genetic Algorithms

In the aerospace industry, many important components are made of ring forgings with characteristics of multi-variety and multi-batch. Such components have many steps and complex parameters in the thermoforming process. The process orders are dynamic and time-varying, and, thus, optimizing the total production time and energy consumption is difficult. To solve the mentioned troublesome and time-consuming problem, this work transformed the workpiece’s required heating temperature and time index into the furnace temperature change and holding time index. Based on a genetic algorithm, an integrated production scheduling optimization of ring forging heating and model forming was established. The genetic algorithm for model improvement was optimized. The optimization objective was changed by using different fitness calculation methods. A multi-time simulation algorithm was designed to calculate each heating furnace’s time and furnace temperature. The proposed optimization method was used for a thermoforming process of ring forgings. When the optimization objective was designed to consider energy consumption and time consumption comprehensively, the average time saving was 6.93%, and the average energy saving was 12.99%. When the optimization objective was designed to prioritize energy consumption, the average time saving was 3.89%, and the average energy saving was 16.53%. When the optimization objective was designed to prioritize time consumption, the average time saving was 10.35%, and the average energy saving was 10.63%. Using the scheduling results for production, compared with the practical factory data, the errors in the simulation time and energy consumption were 2.4% and 1.6%. The results show that the scheduling efficiency of integrated thermoforming production is significantly improved by using this optimization model, and the simulation results have high reliability. The energy consumption of orders is greatly reduced, and the total production time is greatly shortened.

Point cloud model simplification method for ring forgings based on single median error metric

Point cloud model simplification method for ring forgings based on single median error metric

Management Control and Integration Technology of Intelligent Production Line for Multi-Variety and Complex Aerospace Ring Forgings: A Review

Large and complex ring forgings are key structural parts of the aerospace field, and their quality is closely related to the reliability of aerospace vehicles. However, high-quality production of aerospace ring forgings faces many problems, such as the long process design cycle and impoverished consistency, the difficulties of real-time detection under the severe time-varying state of the deformation process, the complexity of high-quality non-destructive testing under multitudinous defects, and the cumbersome management control of the multi-source and multi-dimensional heterogeneous data. Considering the current situation of multi-variety and multi-batch production for aerospace ring forgings, establishing an intelligent production line is a crucial means to solving the above problems and realizing the standardization and premiumization of key aerospace components. Therefore, management control and integration technology of the intelligent production line play a crucial role. An analysis, including the research progress of the intelligent computer-aided process planning (CAPP) system, the real-time detection and control system, the product quality testing system, and the intelligent management control and integration system, is systematically reviewed in this work. Through intelligently managing and controlling the integrated systems of the production line, the production efficiency of ring forgings can be effectively improved, and the production energy consumption can be remarkably reduced, which is of great significance for enhancing the manufacturing technology level of aerospace products.

Research on the size of ring forgings based on image detection and point cloud data matching method

Research on the size of ring forgings based on image detection and point cloud data matching method

The Study of the Metal’s Flow Distribution during Rolling in Cutout Strikers for Different Schemes of the Stress State

In the forging industry, rolling is used to produce ring forgings, which are widely used in power and nuclear engineering. According to the technical conditions and established practice, large ring forgings are made using the operations of precipitation, piercing and rolling out with a striker on the mandrel.

A new section line extraction method of ring forgings based on normal vector and L1-median

Ring forgings are widely used in industrial fields. It is an important way that the key dimensions of ring forgings are obtained by laser scanning to ensure the processing quality. It is difficult to extract high-precision section line of ring forgings from laser point clouds with a lot of noise. This paper presents a new method for extracting section line from raw point cloud of ring forging. An optimization algorithm is created based on the normal vector and L1-median, which is used to iteratively shrink the sampling points for obtaining the section line of ring forgings. L1-median has the characteristics of noise immunity, adding normal vector can get more detailed features. The extraction of high-precision section line of ring forgings is realized. Taking the second-order ring forging and the third-order ring forging as the experimental object, experiments are carried out to verify the effectiveness of the model.

Quantitative ultrasonic testing for near-surface defects of large ring forgings using feature extraction and GA-SVM

Water immersion ultrasonic testing technology is widely used in non-destructive testing of large ring forgings, but near-surface defects are difficult to identify in near-surface blind zone, because the defect echo always overlaps with interface echo. In this article, a method combining signal feature extraction with genetic algorithm optimization support vector machine (GA-SVM) was proposed to realize quantitatively testing of near-surface defects. Firstly, the near-surface artificial defects were machined on the test specimens from the large ring forgings, and a total of 160 signal samples were obtained by water immersion ultrasonic experiments. Then the time-domain features of ultrasonic signals were extracted, the spectrum features were obtained by fast Fourier transform. And the ultrasonic signals were processed by intrinsic time-scale decomposition, and the statistical features of the rotating components with different frequencies were extracted. Finally, three kinds of neural network classifiers were used to identify the size and depth of defects by the features database. The experimental results showed that the identification error of the GA-SVM classifier with the different number of sample databases was always minimal. The ultrasonic testing experiment of near-surface notch defects further verified the correctness and feasibility of the GA-SVM classifier.

Research on outer diameter measurement method of ring forging based on standard deviation resampling

The utilization rate of forging materials and the forging process parameters are affected by the shape and size of forgings. The measurement of the shape and size of forgings plays a key role in forging quality and efficiency of industrial production. At present, the laser measurement method is commonly used in forging measurement. The relatively large errors in the laser measurement are mainly caused by the dust at the measurement site, the angular deviation of the object and laser scanner, and the system error of the laser scanner. Therefore, a measurement method of outer diameter of ring forgings based on standard deviation algorithm is presented in this paper. Firstly, after resampling by the standard deviation algorithm, the more accurate data are obtained. Secondly, the good arc feature of the point cloud data is obtained by means of mean filter. Finally, the outer diameter of ring forgings is obtained by using ellipse fitting based on least squares principle. The feasibility of this method is verified by measuring two ring forgings with different outer diameters in the experiment.

Cold bulging process for aluminium alloy ring with irregular section

Large size aluminium alloy seamless ring with irregular section is usually obtained by hot ring rolling process. Because of residual stress, the ring generally experiences much deflection during subsequent aging and machining. To control this deflection and strengthen the aluminium alloy ring, cold bulging process has to be applied to the ring to homogenize residual stress before aging and machining, and the uniformity of cold deformation is the key problem. The cold bulging process was designed for the forging of the casing ring of aluminium alloy with 5-meter special-shaped section. On this basis, the stress analysis of the cold bulging process was made and the process was engineered. By using Deform-3D to conduct finite element analysis on the ring cold bulging process and stress analysis on different positions of the ring, the deformation characteristics of the ring under the cold bulging process were obtained. The uniformity of the deformation of the ring was achieved by means of the rotation of the disc die when the ring was bulging. The bulging process in the engineering scheme greatly improved the uniformity of the strain in each region of the ring, which provided a reliable theoretical analysis and engineering scheme for the cold bulging process of the ring forgings of aluminium alloy casing with irregular section.

A new method of processing laser scanning data of radial section dimensions for ring forgings

Ring forgings are widely used in petrochemical, power generation, aerospace, nuclear industry and other industrial fields. In the forging process, the radial section size data greatly affect the forging accuracy of ring forgings. Therefore, a new method of processing laser scanning data of radial section dimensions for ring forgings is proposed. Firstly, the information space set of laser scanning data is established. This information space is divided by continuous concentric circles. Secondly, according to the information relationship between the various areas in the information space, the uniform isomorphism factor is defined. By combining the gradient descent method with the uniform isomorphic factor, the undetermined coefficients are solved. Thirdly, the reduction ratio is set according to the density of scanning data points. By combining the reduction ratio with the undetermined coefficients, the number of points needed to be reserved in each area of a concentric circle is determined. The remaining points and the repetitive points in the intersection of two concentric circles are deleted. Finally, the method is repeated until the last point of the laser scanning data. In this way, the laser scanning data of radial section for ring forging is processed. When the method is applied in the experiment, the size data of radial section is extracted from the processing data of laser scanning radial section line. Two groups of dimension data measurement experiment for standard and non-standard ring forgings are carried out respectively. The dimensions measured from the unprocessed and processed data points are compared with true values. The dimensions measured from the processed data have higher accuracy and smaller error. The feasibility of this method is proved.

A stitching method of radial section line of scanned point cloud data for ring forgings

The dimensions of ring forgings can be analyzed by the point cloud data of ring forgings scanned by laser. The dimensions are the key to evaluating the parameters of ring forgings. Due to the limitation of the scanning angle of the laser scanner, the complete data of the radial section line for the ring forging cannot be obtained through one scan. So the point cloud data of multiple scans are stitched to get the complete data of radial section line. In response to the stitching question, a point cloud data stitching method for ring forgings is proposed in this study. Firstly, the coarse stitching is carried out by using the relationship between the center coordinates of the two data sets. Then, the repeated region is found by the improved Beetle Antennae Search Algorithm (BASA). The repeated region is divided into three parts to find corresponding points in the process of precise stitching. The complete radial section line data can be obtained. Finally, the stitched radial section line is transformed into a complete 3D ring forging model. The comparison experiment results show that the algorithm proposed in this study is simple and fast. The accuracy of this algorithm is verified by extracting the dimensions of the complete model for ring forging.

The mixed production mode considering continuous and intermittent processing for an energy-efficient hybrid flow shop scheduling

Abstract Energy-saving scheduling in forging production has attracted increasing attention because of the advances in sustainable manufacturing technologies. The unit energy consumption of forging production equipment is significantly higher than that of other general manufacturing equipment. Employing efficient and energy-saving scheduling methods can significantly reduce the energy consumption in forging production. However, the relationship between heating furnace and other equipment in forging production is complicated, resulting in few studies on energy-saving scheduling problem for forging production line. Thus, the energy-efficient hybrid flow shop scheduling problem with forging operations (EHFSP-FO) was investigated in this research. First, the production mode considering multiple time factors and mixed production was established. The mixed production mode consisted of continuous processing with variable parameters and intermittent processing. Then, a novel mathematical model considering makespan and energy consumption was constructed based on the mixed production mode for the proposed problem, and a new rule to identify the optimum transportation sequence and time was formulated. Furthermore, the population and major operators were designed and applied to an evolutionary algorithm by weighted sum approach. The scheduling results were achieved based on the real-world process data for different types of ring forgings to verify the feasibility of the established mathematical model. The experimental results demonstrated that the proposed mathematical model can be used to identify the optimal schedule considering makespan and energy consumption simultaneously.

Online measuring method of radial section line for ring forgings

Ring forgings are widely used in industrial fields such as trains, construction machinery, bearings, ships, petrochemicals, power generation, aerospace, and nuclear industries. In the dynamic manufacturing process of forgings, the online measurement of radial section line and various dimensional data plays a crucial role in controlling the dimensional accuracy and reducing the reject rate. Therefore, an online measurement method of radial section line for ring forgings based on line laser scanning is proposed. First, a laser scanning measurement system is established for this method. The laser scanning data of the radial uppermost layer section is obtained through this system. Second, all the point cloud data is described as a topological space. The double inverse limit space of the original two-dimensional point cloud information space is established. The topological transitivity between these two spaces is studied. Third, according to the study of the topological transitivity, the relationship of the coordinate position between each point is obtained. Then, a complete radial section line of ring forgings is formed. Finally, the radial dimension data of ring forgings is obtained. Two groups of dimensional measurement experiments have been done. One of the experimental objects is standard ring forging, the other of the experimental objects is non-standard ring forging. The result of the experiment shows that all errors satisfy the requirement of measurement precision.

Reduced algorithm of laser measurement data for geometric parameters of ring forgings based on Artificial Immune Algorithm

Measuring the geometric parameters of ring forgings by laser scanner is an important way to ensure the quality of processing. However, the amount of data obtained by scanner is huge and the noise is complex. The process of data processing is slow. It is impossible to ensure the real-time quality monitoring. Therefore, an improved Quadratic Error Metric (QEM) point cloud data reduction algorithm based on Artificial Immune Algorithm (AIA) is proposed in this study. As for AIA, the choice of antigen and antibody is the critical step. The candidate point cloud is used as the antibody. The antigen is divided into two parts. The first part is the cost function. The cost function is made up of the squares sum of the volumes for two tetrahedra. This is an improved algorithm of QEM. The second part is the optimal solution of the cost function. The antibodies are screened by using the specific reactions between antigens and antibodies, antibodies and antibodies. The point cloud data can be reduced by these specific reactions. Finally, the algorithm is applied to the experiment of measuring the geometric parameters of typical ring forging. The experimental results show that the reduced data can quickly reconstruct the model. The precision of the size parameters for the model can be ensured through the algorithm proposed in the study. Through the comparison experiments, the advantages of the reduced method of the algorithm are further proved. Meanwhile, the real-time performance of the on-line monitoring of the quality for the ring forging can be improved. The measuring method proposed is feasible according to the experimental results.

Manufacture of Large Disc and Ring Forgings in Alloy 600

Saarschmiede has focused on the development of large remelted Ni-based alloy forgings, typically used for research and development projects in the field of the power generation industry and the nuclear industry. Across these industrial sectors, there is a drive towards larger forgings with consistent mechanical properties, low levels of chemical segregation, and high requirements on the ultrasonic testability, for example, the increasing of the sensitivity. In light of this, Saarschmiede has focused on improving the maximum ingot sizes, ingot yield, hot working processes, and also the heat treatment cycles to meet the requirements of these highly regulated industries. Over the last three years, Saarschmiede has manufactured several large disc and ring forgings from Alloy 600 with a maximum forging weight of approximately 30 tons. These forgings were manufactured from several Electro Slag Remelted (ESR) ingots with a diameter of 1300 mm and a maximum ingot weight of 70 tons. This was, according to our knowledge, the worldwide biggest ingot in this grade ever produced at this time. This paper discusses the manufacturing route, the mechanical properties, the microstructure, and the Non-destructive Evaluation (NDE) for these disc and rings. It also includes a customer perspective on product quality.

Online measuring method of the axial section line in ring forging process

The axial section line of the ring forging is the key parameter to measure whether the ring forging process meets the technical requirements. To ensure the quality of the ring forgings, an online measuring method of the axial section line in ring forging process is proposed in this study. First, the axial section line data of the ring forging is obtained online by laser scanning device. Then, the axial section line data is locally sorted and is screened to eliminate the edge noise. Second, the axial section line data is converted to line grey image data by merger and derivation theory. Finally, the line grey image data is smoothed by bilateral filtering based on information entropy selection factor. Then, the shape of the axial section line is constructed to complete the measurement of the axial section line. The experimental results show that the measurement speed of axial section line meets the requirements and the measurement accuracy of the axial section line meets the requirements.