Untersuchungen zum abrasiven Verschleiß von niedrig- bzw. hoch legierten Kunststoff-Formenstählen mit einem verbesserten Verschleißmodell

Translated title of the contribution: Examinations on abrasion of low alloyed and high alloyed plastic-mould steels with an improved abrasion model

Georg Weiermair

Research output: ThesisDiploma Thesis

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Abstract

On plastic processing machines abrasion occurs mainly on screws, cylinders, non-return valves and on the tool itself. On the one hand this means higher costs for replacement parts as well as for maintenance and on the other hand the running life can be cut. The physico - chemical processes occurring during the abrasion process can be divided into the following main mechanisms: abrasion, adhesion and corrosion. The abrasion apparatus with integrated measurement technique, developed at the Institute for Plastic Processing, allows a better reproducibility of the abrasive/corrosive abrasion determination on the plastics-mould steel for a tribological system "plastic melt/steel" within a shorter time frame. The aim of this thesis is to develop a software for calculating more precisely the specific abrasion work, considering the enlargement of the abrasion channel and the thereby changing shear stress and viscosity. The calculation is based on the abrasion model according to Langecker and shall be verified experimentally with the abrasion apparatus with integrated measurement technique. Furthermore the abrasion work is to assign correctly to their initiators (fibres and polymer). The abrasive/corrosive wear has to be checked with two selected steel types (Böhler M200 and Böhler M300) and three different PA66-types, filled with glass fibres. Additionally the wear behaviour of six M200 specimens, nitrided with 6 different nitriding methods shall be investigated experimentally. The specific abrasion work is a physical value for the work which needs to be done on the one hand for the compression flow of the melt through the abrasion channel and on the other hand the succeeding abrasion which occurs on the steel surface (micro chipping). Mainly it consists of the shares of the pure fibre and the pure unreinforced melt. Until now the calculation of the specific abrasion work was only done using average values of the wear channel height, the wall shear stress, the melt temperature and the resulting average value of the melt viscosity. With the aid of the developed iterative calculation method it is possible to calculate more precisely the abrasion work in every case of over-extruded volume of polymer according to the changing abrasion channel height and the resulting change of viscosity. Furthermore the calculated specific abrasion work can be assigned to their initiator (fibres or melt) more precisely. In comparison with the non nitrided steel specimens the nitrided ones show an excellent abrasion resistance.
Translated title of the contributionExaminations on abrasion of low alloyed and high alloyed plastic-mould steels with an improved abrasion model
Original languageGerman
QualificationDipl.-Ing.
Supervisors/Advisors
  • Friesenbichler, Walter, Co-Supervisor (internal)
  • Langecker, Günter R., Supervisor (internal)
Award date19 Dec 2008
Publication statusPublished - 2008

Bibliographical note

embargoed until null

Keywords

  • polymer processing machine abrasion tribology adhesion corrosion fillers glass fibers compound abrasion work friction energy

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