Prestressing of cold forging tools for parts with functional elements

Killmann M, Merklein M (2022)


Publication Language: English

Publication Status: Accepted

Publication Type: Conference contribution, Conference Contribution

Future Publication Type: Journal article

Publication year: 2022

Edited Volumes: XL. Verformungskundliches Kolloquium

Series: XL. Colloquium on Metal Forming

Pages Range: 39 - 44

Conference Proceedings Title: XL. Colloquium on Metal Forming

Event location: Zauchensee AT

ISBN: 978-3-902078-27-8

Abstract

An increasing demand for complex part geometries poses challenges to the fatigue strength of cold forging tools. When producing functional elements like gears or carriers, local stress peaks occur in the forging dies. To avoid fatigue failure, an analysis of the stress state and adequate prestressing strategies for non-circular symmetrical cold forging tools are necessary. Therefore, a model process for the closed-die forging of four functional elements is introduced and the resulting stress state analysed numerically. While high compressive stresses and radial displacements are present between the functional elements, there is a tensile stress area with tangential stresses critical for fatigue failure at the head of the functional elements. To counteract this, a local prestressing of functional elements by stress pins is proposed. The pins are pressed into the tool, locally creating radial compressive and tangential tensile stresses. They are well suited for geometries with functional elements, because there are no undesired interactions between pin and process tensile stresses. Even the stress state in tools for more complex part geometries with a higher number of functional elements can be improved that way. However, the height of the local prestressing is still limited by tensile stresses around the pin.

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APA:

Killmann, M., & Merklein, M. (2022). Prestressing of cold forging tools for parts with functional elements. In Lehrstuhl für Umformtechnik, Montanuniversität Leoben, Martin Stockinger (Eds.), XL. Colloquium on Metal Forming (pp. 39 - 44). Zauchensee, AT.

MLA:

Killmann, Martin, and Marion Merklein. "Prestressing of cold forging tools for parts with functional elements." Proceedings of the XL. Colloquium on Metal Forming, Zauchensee Ed. Lehrstuhl für Umformtechnik, Montanuniversität Leoben, Martin Stockinger, 2022. 39 - 44.

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