Manufacturing Of High-Performance Forging Dies By Ausforming

authored by: Bernd Arno Behrens, Kai Brunotte, Michael Till
Abstract: During forging, dies are subject to a complex load collective caused by combined thermally and mechanically induced stresses. Crack formation and deformation on tool surfaces, as a result of low fatigue resistance, lead to tool failure and high process costs. Grain refinement is regarded as a method to improve fatigue resistance due to enhanced ductile material properties. To generate a fine-grained microstructure in the die material, increased deformation can be applied in the metastable austenite phase, also known as ausforming. In this study, the thermo-mechanical treatment ausforming will be used to form the final contour of forging dies. For this purpose, an analogy study was performed in which a preform is ausformed. It is investigated to what extent a fine-grained microstructure can be achieved in the final forming stage. The hot-working steel X37CrMoV5-1 (AISI H11) was used as specimen material. The developed sample geometry represents the inner contour of a highly mechanically loaded forging die. To achieve optimal properties, process routes with different cooling strategies and two defined true plastic strains were examined in metallographic analysis and hardness measurements according to EN ISO 6507-1 (HV1). It is shown that, after complete austenitisation, the highest hardness values can be achieved by applying a water-air spray cooling with subsequent forming. This could be demonstrated without material failure in the samples even with a high true plastic strain.
Organisation(s): Institute of Metal Forming and Metal Forming Machines
Type: Conference contribution
Pages: 203-208
No. of pages: 6
Publication date: 27.07.2020
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Mechanics of Materials, Metals and Alloys, Surfaces, Coatings and Films
Electronic version(s): https://doi.org/10.37904/metal.2020.3471 (Access: Open)
: Details in the research portal "Research@Leibniz University"

BibTeX

@inproceedings{790e5d19475c47d8ab9663f71c8017fb,
title = "Manufacturing Of High-Performance Forging Dies By Ausforming",
abstract = "During forging, dies are subject to a complex load collective caused by combined thermally and mechanically induced stresses. Crack formation and deformation on tool surfaces, as a result of low fatigue resistance, lead to tool failure and high process costs. Grain refinement is regarded as a method to improve fatigue resistance due to enhanced ductile material properties. To generate a fine-grained microstructure in the die material, increased deformation can be applied in the metastable austenite phase, also known as ausforming. In this study, the thermo-mechanical treatment ausforming will be used to form the final contour of forging dies. For this purpose, an analogy study was performed in which a preform is ausformed. It is investigated to what extent a fine-grained microstructure can be achieved in the final forming stage. The hot-working steel X37CrMoV5-1 (AISI H11) was used as specimen material. The developed sample geometry represents the inner contour of a highly mechanically loaded forging die. To achieve optimal properties, process routes with different cooling strategies and two defined true plastic strains were examined in metallographic analysis and hardness measurements according to EN ISO 6507-1 (HV1). It is shown that, after complete austenitisation, the highest hardness values can be achieved by applying a water-air spray cooling with subsequent forming. This could be demonstrated without material failure in the samples even with a high true plastic strain.",
keywords = "Ausforming, Cooling rate, Metastable austenite, True plastic strain",
author = "Behrens, {Bernd Arno} and Kai Brunotte and Michael Till",
note = "Funding Information: The results presented were obtained in the research project „Development and Investigation of Mechanical Properties of Hot Forging Dies by Bulk Forming and Thermomechanical Treatment” financed under project number 318628894 by the German Research Foundation (DFG). The authors would like to thank the DFG for financial support. ; 29th International Conference on Metallurgy and Materials, METAL 2020 ; Conference date: 20-05-2020 Through 22-05-2020",
year = "2020",
month = jul,
day = "27",
doi = "10.37904/metal.2020.3471",
language = "English",
pages = "203--208",
booktitle = "Proceedings 29th International Conference on Metallurgy and Materials",
publisher = "TANGER Ltd.",
}