13th International Conference on the Technology of Plasticity (ICTP 2021): Forging
Program Organizers: Glenn Daehn, Ohio State University; Libby Culley, The Ohio State University; Anupam Vivek, Ohio State University; Jian Cao, Northwestern University; Brad Kinsey, University of New Hampshire; Erman Tekkaya, TU Dortmund; Yoshinori Yoshida, Gifu University
Wednesday 9:15 AM
July 28, 2021
Room: Virtual: Room E
Location: Virtual
Session Chair: Wuhao Zhuang, Wuhan University of Technology
Optimization of Open-die Forging Using Fast Models for Strain, Temperature and Grain Size in the Context of an Assistance System: Fridtjof Rudolph1; Martin Wolfgarten1; Viktor Keray1; Gerhard Hirt1; 1IBF - Institute of Metal Forming, RWTH Aachen University
Besides achieving the intended final shape, one main aim of open-die forging is the adjustment of the mechanical properties by transforming the cast structure into a fine-grained microstructure. To achieve this the process needs to be designed in a way that ensures achieving all required part properties, such as grain size, which up to now often requires a lot of operator experience. This paper presents the concept of a forging assistance system, since during forging small deviations from the previously designed pass-schedule might add up to unacceptable errors.Such an assistance system requires the evolution of part geometry and surface temperature as input, which are captured with a thermographic camera. The assistance system then uses fast models for equivalent strain, temperature and microstructure which allow calculation of these properties for the core fibre within seconds on the basis of semi-empirical and physical formulae. However, in the context of an assistance system, which gives real-time advice in case of process deviations, these calculation times are still fairy long, if the hundreds of iteration necessary for process optimization are taken into account. Therefore, three scenarios of deviations, which have to be solved within different time frames, are examined to explore the limits of the chosen classical optimization algorithm.
Galling-free Micro-forging of Titanium Wire with High Reduction in Thickness by Beta-SiC Dies: Tatsuhiko Aizawa1; Koh-Ichi Ito2; Tatsuya Fukuda2; 1Nano Coat Film, LLC.; 2Tokai ENgineering Service, Co., Ltd.
Pure titanium as well as beta-type titanium alloys are difficult to be shaped into parts and tools by the stamping and forging. In particular, this chemical galling prevented titanium and titanium alloys from net shaping for medical parts and fine tools. In the present study, beta-type SiC coated SiC punch and die was developed to demonstrate that upsetting with the reduction in thickness by 60 % becomes free from metallic titanium transfer to die and punch surfaces. A pure titanium wire with the diameter of 0.98 mm was prepared for upsetting experiments by the CNC (Computer Numerically Control) micro-forging system. The relationship between measured torque and stroke reveals that pure titanium circular wire plastically deformed to a triangular pin by 60 % in reduction. SEM-EDX proved that no metallic titanium transferred onto the die and punch surface.
Development of Automatic Design System for Closed Die Forging Process of Disk-shaped Products: Yoshihiko Kobayashi1; Eiji Sakamoto1; Tetsuya Yagami1; 1Hitachi, Ltd.
In the process design of closed die forging, various design conditions such as the number of stage and the die-surface shape for each stage are determined by a designer considering the process requirements; load restriction, forged shape accuracy, and so on. During the process design, it is a problem that these design conditions have a lot of combinations. For this reason, a forging process has usually considered by trial and error using CAE or real machine. In particular, there are numerous patterns for the combination of the number of stage and the die-surface shape for each stage, which is called process layout. Researches for improving design-operations efficiency have been performed. Nevertheless, the process-layout design is still dependent on trial-and-error approach. In this study, to improve the efficiency about process-layout design, automatic design system using CAE was developed for closed die forging of disk-shaped products.
General Step Reduction and Enlargement Method for Knowledge-based Process Planning of Totally Non-axisymmetric Forged Products with Blanking and Punching: Masanobu Umeda1; Yuji Mure2; Keiichi Katamine1; Kazuya Matsunaga1; 1Kyushu Institute of Technology; 2Kagoshima Prefectural Institute of Industrial Technology
A forging process planning method, including blanking and punching, termed General Step Reduction and Enlargement (GeneSteR+E), is discussed for cold- and warm-forged products. It is applicable to non-axisymmetric forged products that consist totally of non-axisymmetric shape elements, and can generate multiple process plans without relying on design cases. The shape of a forged product is split into outer and inner shapes, which are then split into axisymmetric and non-axisymmetric shape representation units termed basic elements (BEs) according to shape separation rules. Process plans are generated in a reverse order from a final forged product by applying shape transformation rules that reduce the number of steps between BEs until a billet (or a blank) is obtained. The shape transformation rules are defined not only for forging, but also blanking and punching. An experimental knowledge base was implemented and applied to several non-axisymmetric forged products, such as an electrical connector. The results show that the GeneSteR+E method is applicable to the design of forging process including blanking and punching of totally non-axisymmetric products, and can generate satisfactory process plans comparable to those developed by anexperienced engineer.
Investigation of Failure Mechanisms of Cemented Carbide Fine Blanking Punches by Means of Process Forces and Acoustic Emission: Herman Voigts1; Rafael Hild1; Andreas Feuerhack1; Thomas Bergs1; 1Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University
Due to the processing of materials with ever greater strength in fine blanking, the lifetime of conventional high-speed steel punches decrease rapidly. Materials with a higher wear resistance and compressive strength, such as cemented carbide, are investigated for the use in fine blanking processes. However, cemented carbide punches of-ten fracture during the stripping off phase due to the combined tensile and flexural stress collective. The under-standing of fracture mechanisms and subsequent fracture prevention supports the application of cemented car-bides. The fracture mechanisms during stripping off are mostly unknown. The objective is to identify fracture mechanisms of cemented carbide punches. The fracture of cemented carbide punches was metrologically moni-tored by means of acoustic emission (AE) and process forces. The fracture pattern was analyzed related to the measured signals. In order to interpret the AE-signal, basic process analyses were performed. Subsequently, a punch fracture of cemented carbide was provoked with the high-strength material S700MC. Cemented carbide punches tend to fracture during stripping off as a cause of tensile and flexural loads due to asymmetrical interactions with the scrap web.
A FE Billet Model and A Spring-mass-damper Press Model for the Simulation of Dynamic Forging Process: Application to a Screw Press: Jean-François Mull1; Camille Durand1; Cyrille Baudouin1; Régis Bigot1; M. Heyu Song1; 1Université de Lorraine, Arts et Métiers ParisTech
In forging processes, the determination of blow efficiency is very important, as it quantifies the part of the stroke energy actually transmitted to the billet. Thus, forging processes should be deeply analyzed in order to better understand the stroke energy conversion, accurately estimate blows efficiency and thus better predict process parameters. In this paper, a spring-mass-damping vibration model is proposed to describe the behavior of a screw press. A simulation of the upsetting of copper specimen is performed with a FE software with no consideration of the press behavior. Then, forging load from the FE simulation is used to perform simulation of the whole forging process with the press model. Results show that the model is relevant to simulate forging load and ram displacement. Moreover, simulation can predict the distribution of the energy during the simulation and the blow efficiency can be calculated. This new way to obtain blow efficiency might improve productivity in process development and provide a better understanding of energy driven machine.
Compression of C/Thermoplastic Printed Composite; Shaping Parameters and Material Health: Victor Haguenauer1; Eric Becker1; Ludovic Freund1; Damien Felix2; Regis Bigot1; 1Arts et Métiers Institue of Technology; 2Setforge Engineering
The EPITHER process is an innovative way of shaping C/Thermoplastic composite materials to produce massive structural parts that combine the strength of CRFT composite materials with the high production rates of forging. Composite structural parts contribute to the reduction of CO2 emissions by reducing weight, especially those in motion for power transmission. This process has a preforming step necessary for the placement and orientation of continuous carbon fiber composites necessary to increase their characteristics. In this study, this preforming step is performed by 3D printing. In order to obtain finished products with good dimensional and material characteristics, this study provides elements for optimizing certain process parameters and the associated results, particularly at different steps in the forming process.