Einfluss des Einspritzvolumenstroms auf die Verschleißfestigkeit eines hochchromhaltigen martensitischen pulvermetallurgischen Stahls

Translated title of the contribution: Influence of injection rate on wear resistance of a high-chromate martensitic powder metallurgically steel

Tobias Schmidt

    Research output: ThesisMaster's Thesis


    In the injection moulding industry wear of certain machine parts is becoming a bigger issue due to increasing output rates. Additionally, to the increasing mass flow, nowadays a very high content of filler materials such as glass fibers are induced into the polymeric matrix. The combination of the mentioned influencing factors results in more frequently failure of melt conveying machine parts. Hereby, the plasticizing is strongly affected. Due to the influence of several factors, as geometry, pairing of different materials (e.g. polymer and metal) and different wear mechanisms, wear has to be considered as a complex parameter. To investigate wear, generated by the interaction of a filled polymer melt and a metal component, of especially the plasticizing unit in the injection moulding process, a self-manufactured test mould at the institute of polymer processing of Montanuniversitaet was applied, developed according to the DKI platelets method in DIN 50322. The main aim was to determine test parameters, which lead to reproducible and comparable results. To obtain these parameters, material loss due to wear in mg as a functin of injected materisal and injection rate was investigated. Considering the material pairing – polymer melt/metal, Polyamid 6.6 reinforced with 50 wt% glass fibers was utilized as polymer and as metal a powder metallurgically manufactured martensitic steel was applied. The performed experiments were divided into two test series. According to test series 1 the injection rate was kept constant and the mass of injected polymer melt varied. Whereas, in test series 2, the injection rate was varied, and the injected polymer mass was kept constant. With increasing injected mass as well as higher injection rates stronger wear could be observed. Though, no linear relation between mass loss due to wear and injected mass and injection rate respectively could be observed. But increasing injection rate has a strong impact on melt temperature due to viscous dissipation. In case of highest injection rates the hardness of the worn surface of the etallic specimen decreased significantly. For a better interpretation of the obtained results, measured weight differences of the wear specimens, surface images as well as hardness measurements at the worn surface were made. Additionally, deviations of the machine in injection rate were recorded and used for further studies. As well samples of injected melt at different injection rates and positions along the melt flow (granulte, material after dosing, material after injection through the wear gap) were prepared for subsequent analysis of fiber length and fiber length distribution.
    Translated title of the contributionInfluence of injection rate on wear resistance of a high-chromate martensitic powder metallurgically steel
    Original languageGerman
    Awarding Institution
    • Montanuniversität
    • Friesenbichler, Walter, Supervisor (internal)
    • Blutmager, Andreas, Co-Supervisor (external)
    Award date19 Oct 2018
    Publication statusPublished - 2018

    Bibliographical note

    embargoed until 01-08-2023


    • tribology
    • injection moulding
    • wear

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