13th International Conference on the Technology of Plasticity (ICTP 2021): Lubrication and Surface Effects
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
Friday 10:20 AM
July 30, 2021
Room: Virtual: Room E
Location: Virtual
Session Chair: Werner Homberg, Paderborn University
Development of Oil-type Lubricants for Cold Forging Using Phase Transition Behavior Under High-pressure Conditions: Tomoaki Okano1; Nobuhide Tanino1; Kazuhiko Kitamura2; 1Idemitsu Kosan Co., Ltd.; 2Nagoya Institute of Technology
In the process of cold forging, lubricant is one of the important elements because they contribute to prolong the die life and improve the surface quality of products. On the other hand, it is well known that lubricants are exposed to the very severe condition such as high contact pressure and high temperature induced by processing heat. So that, oil type cold forging lubricants cause oil film shortage and induce processing defect. In order to make a breakthrough in these situations, we find out the possibility of phase transition materials from liquid to solid under high-pressure conditions. In this research, we develop new oil type lubricants for cold forging using phase transition materials. Moreover, we find that these materials show higher lubricating performance for cold forging process compared with the conventional lubricants. These results indicate that phase transition behavior under high-pressure conditions support the lubrication for cold forging process.
Analysis of Work Hardening and Tribological Changes after a Gap Controlled Drawbead Passage: Harald Schmid1; Marion Merklein1; 1FAU Erlangen-Nürnberg, Institute of Manufacturing Technology
In deep drawing processes, drawbeads are frequently used to control material flow while forming. It is well-known, that material parameters are changed significantly after a drawbead passage. Also, there are many references that the tribological system after a drawbead is changed and that this has influences on the ongoing forming process. In this study, the connection between work hardening and the tribological system after a drawbead is analyzed with respect to the initial state. Therefore, sheets are drawn through a gap controlled drawbead passage while parameters like the gap between blank holder and die or the materials are varied. Afterwards, hardness measurements will be carried out as well as 3D surface measurements to correlate them. For these investigations, three different sheet metals are used: a conventional deep drawing steel, an advanced high strength steel AHSS and an aluminum alloy, as they represent the variety of industrial used sheet metal.
Evaluation of Lubricant Performance for Thick Sheet Ironing Process by Ball Ironing Test: Nuttakorn Sae-eaw1; Yingyot Aue-u-lan1; 1King Mongkut's University of Technology North Bangkok
A thick sheet ironing process is normally used to control the uniform wall thickness of products. To evaluate the performance of lubricants by conventional tests, such as Ring Compression Test (RCT) is not suitable due to the limitation in the low level of normal contact pressure, surface expansion, and relative velocity. In this research, Ball Ironing Test (BIT) was proposed as a new simulative tribo-test. Finite Element Modeling (FEM) together with the statistical analysis was employed during the design and determine the frictional indicator of the BIT. According to the results, the maximum load is very sensitive to the friction and can be used as an indicator to evaluate and approximate the friction coefficient via Frictional Calibration Curve. Different types of lubricants were tested experimentally and demonstrated different performance during the BIT. In conclusion, the BIT is suitable for evaluating the ironing process.
Investigations on Dynamic Characteristics of a Mechanical Press Considering Both Translational Clearance Joint and Lubrication Effect: Xuze Wu1; Yu Sun1; 1Nanjing University of Science and Technology
The existence of clearance in the motion joints of multi-body systems can significantly influence the dynamic responses. Distinguished from the previous studies, the inclination characteristics of the slider, which are crucial in the stamping forming process, are analyzed in this paper. To achieve a higher analysis accuracy, lubrication actions are introduced to the dynamic equations, and contact forces evaluated by the L-N dry contact model are also considered. Numerical simulations were carried out to investigate the influence of clearance size and crank speed. Then, Poincaré maps and spectrum graphs were adopted to indicate the regularity of the system responses. Furthermore, experimental validations were achieved based on the testing system for a mechanical press. It indicates that the translational clearance joint can play a vital role in the slider inclination issue, and will lead the system dynamics into chaos with a specific range of parameters.