Manufacture of Toothed Elements in Nanoausferritic Ductile Iron

Abstract

The technology currently used for the fabrication of toothed wheels, gear couplings and chain drums involves the induction hardening process or hardening and tempering after carburising. All these processes take a long time and cause adverse changes in the dimensions and surface quality of products, requiring post-treatment machining to remove the resulting cavities. The paper proposes the implementation of gear elements made of ductile iron with nanoausferritic matrix obtained by a new appropriate heat treatment process. The new material offers good performance characteristics and nearly no need for the application of other technological processes commonly used in the manufacture of gears.Keywords: austempered ductile iron, nanoausferritic matrix, austempering, toothed elementsObecnie stosowany proces projektowania kół zębatych zakłada hartowanie indukcyjne uzębienia po procesach ulepszania cieplnego lub hartowanie i odpuszczanie po nawęglaniu. Procesy te są długotrwałe i powodują niekorzystne zmiany wymiarów wyrobu oraz zmiany powierzchniowe, które muszą być usunięte poprzez obróbkę skrawaniem. W artykule zaproponowano wykonanie kół zębatych z żeliwa o osnowie nanoausferrytu uzyskaną w wyniku odpowiednich procesów cieplnych. Nowy materiał oferuje dobre właściwości użytkowe oraz możliwości w ograniczeniu procesów technologicznych wykonywanych przy wytwarzaniu kół zębatych.

Capability of New High Strength ADI‐Materials for Automotive Components under Crash Loading

“…This is a known mechanism also for ADI materials (see e.g. ). The here quantified austenite transformation confirms such a TRIP effect under quasistatic and crash‐similar loading situations, which might be the reason for the observed high strength values in combination with relatively large elongations at fracture of the ADI qualities under investigation.…”

“…under mechanical load (TRIP effect). The material properties are very sensitive to the process parameters. Therefore, within the German research project LEA (Light Weight Construction with Cast ADI‐Components ) the process chain was investigated and optimized in detail in order to enable the development of optimized new high strength ADI (Austempered Ductile Iron) in ADI 1000 and ADI 1200 qualities.…”

The Comparative Study of the Microstructure and Phase Composition of Nanoausferritic Ductile Iron Alloy Using SEM, TEM, Magnetometer, and X-Ray Diffraction Methods

“…Electron diffraction patterns analysis revealed that the microstructure consisted of thin bainitic ferrite plates separated by thin layers of retained austenite. In case of steels this kind of microstructure is called nanobainite [13][14][15], while in ductile iron we can speak of nanoausferrite [6,7]. The average width of ferritic plates was similar for both samples and it was 126 ± 13 nm and 116 ± 7 nm in ADI-1 and ADI-2, respectively.…”

“…One of directions of the research work was to produce the alloys with nanocrystalline microstructure and precisely designed phase composition [4][5][6][7]. However, to control the phase composition, especially the content of the retained austenite is not an easy task and needs application of the accurate methods of phases volume fraction determination.…”

Multiphase Ausformed Austempered Ductile Iron

“…5 shows that the ferrite aggregates build up from many ferrite plates in the same crystallographic orientation. Myszka et al reported that isothermal transformation of ausferrite refines the ferrite plates which tend to form a typical feathery pattern indicating the direction of the plate growth [12]. It is obvious in Fig.…”