Abstract
The study performs an overview and evaluation of the currently applied methods of preheating forging tools used in hot die forging processes performed on presses and presents the development and tests of new, more effective methods. Based on the conducted complex analysis of the temperature changes taking place on and directly beneath the surface of forging dies during their preliminary heating, an analysis was performed of one of the most commonly used methods of tool heating, i.e., using a charge material and a waste material. Next, the study proposes the introduction of changes and improvements of this method to achieve repeatability and stability of the obtained temperatures. To that end, detailed guidelines concerning the manner and time of the heating process were elaborated. The following step was the development of a new, more effective heating method. The first draft involved a new concept of heating using heaters localized in the die’s housing or heaters in the shape of forgings placed between the dies. Both concepts of heating were numerically modeled, which made it possible to assess their effectiveness. The last step of the research was the development of a heating method using induction heaters. This method was the most effective and brought the best results, which was confirmed during the modeling of the heating process and in the tests conducted on the prototype test stand. The obtained results confirm the effectiveness of almost all the methods, especially the method of heating by means of a charge material, supported by new guidelines, the method of heating with the use of forging-shaped heaters and the method of induction heating. Only in the case of heating with heaters mounted in the tool housing was the assumed working temperature not achieved. Some differences were observed mainly related to efficiency, that is, the heating speed in respect to the assumed temperature. The performed tests showed that the best method is induction heating as it is over twice as fast. Therefore, it is usually recommended for the process of heating and the additional heating realized in the work center of the press on the mounted tools, where the time aspect is especially important.
Highlights
AMONG many metal-forming technologies, hot forging is commonly applied in the production of parts for the machine-building, agricultural, extractive, aircraft and, above all, automotive industry
The main directions of forging industry development are concentrated on improving the quality of the forgings, among others, with the use of precision forging, MAREK HAWRYLUK, PAWEŁ WIDOMSKI, MARCIN KASZUBA, and JAKUB KRAWCZYK are with the Department of Metal Forming, Welding and Metrology, Wroclaw University of Science and Technology, Lukasiewicza Street 5, 50-370 Wrocław, Poland
The tools used in hot forging processes are exposed to many detrimental factors, the most important of which is friction, as well as varying temperatures and pressures.[4,5,6,7]. The occurrence of these destructive mechanisms is inevitable, and they can only be limited by controlling the tool material and tool production technology.[8]
Summary
AMONG many metal-forming technologies, hot forging is commonly applied in the production of parts for the machine-building, agricultural, extractive, aircraft and, above all, automotive industry. The tools used in hot forging processes are exposed to many detrimental factors, the most important of which is friction (abrasive wear), as well as varying temperatures and pressures (thermomechanical fatigue).[4,5,6,7] The occurrence of these destructive mechanisms is inevitable, and they can only be limited by controlling the tool material and tool production technology.[8] in hot forging processes, during the tool’s contact with the hot material of the forging, irregularities are seen, such as overheating or cracking as a result of VOLUME 51A, SEPTEMBER 2020—4753 non-uniform accelerated heating of the tool material. These problems should be eliminated by following proper tool cooling and performing preheating before the forging process begins to avoid non-uniform heating and its accompanying stresses.[9,10] Proper preheating greatly increases the durability of the tool because it reduces the stress and directly helps avoid brittle fractures.[11,12]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
