Vergleichende Untersuchungen über unterschiedliche Reparaturmethoden von Schmiedegesenken

Translated title of the contribution: Comparative studies of different repair methods of forging dies of hot tool steels

Ediz Zafer Mazlum

Research output: ThesisDiploma Thesis

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Abstract

Forging dies of hot tool steels are subjected during the hot forming process by high thermal, mechanical and tribological loading which lead in general to a lower service life of the forging tools. Beside the fatigue cracks and plastic deformation abrasion is in 70% of the cases the main cause of failure. Wear poses a great problem, because the cost of the tools for hot forming accounts for 10 to 20% of the total costs. Due to this high costs fraction there is a high interest to improve the life time of tools and the related economy of production. One possibility to increase the service life of the forging tools and reduce the related tool and production cost is to repair the worn or damaged forging tools and to reuse them. This can be done in the following ways: Repositioning by High Speed Cutting (HSC), overlaying welding, application of thin-film technologies (PVD or CVD) and special surface modifications. In this work the abrasion behaviour under closed-die forging condition of two hot tool steels (Böhler W300 and W360) and the use of welding cladding materials (similar material type and Co base alloy for coating) were tested and compared. The experiments were performed by rotational tribometer, which were developed by the chair of metal forming at Montan University using varying experiment parameters (contact pressure, friction velocity, friction path, temperature). The temperature of the tools was hold at 250°C and the temperature of workpiece is taken to be 1200 °C. The examinations were made with the parameters contact pressure up to 45 kN, friction velocity up to 45 mm/s and a friction path up to 200 mm in order to depict the influence of this varying parameters on the friction and also the occurring wear on the surface of the workpiece as authentic possible. Studies have shown that three of five used additional materials (CastoWIG, Capilla 734, Capilla 733) in overlaying welding are leading to an improvement of the abrased or damaged surface of the tool.
Translated title of the contributionComparative studies of different repair methods of forging dies of hot tool steels
Original languageGerman
QualificationDipl.-Ing.
Supervisors/Advisors
  • Buchmayr, Bruno, Supervisor (internal)
Award date13 Dec 2013
Publication statusPublished - 2013

Bibliographical note

embargoed until null

Keywords

  • forging die
  • hot massive forming
  • overlay welding
  • durability improvement
  • repair methods

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