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.
The research described in this article is a fragment in the series of published works trying to determine the applicability of new materials for parts of the mining machinery. Tests were carried out on the -very popular in mining applications -36HMN steel and three types of the austempered ductile iron, using special stand for the controlled abrasion testing of samples subjected to the effect of loose abrasive. Tests carried out with the use of corundum showed the competitive properties of cast iron as compared with the examined steel. Microscopic evaluation, hardness measurements and magnetic tests showed that the surface layer of austempered ductile iron undergoes a strong work hardening, resulting in abrasion wear indices superior to those of the steel for heavy-duty use.Keywords: austempered ductile iron, wear resistance, microstructural transformactions Badania przestawione w artykule wpisują się w cykl publikacji określających przydatność nowych materiałów na części maszyn górniczych. Testy przeprowadzono dla popularnej w zastosowaniach górniczych -stali 36HMN i trzech rodzajów żeliwa sferoidalnego ausferrytycznego, na specjalnym stanowisku do kontrolowanego ścierania próbek suchym ścierniwem. Badania zrealizowane z użyciem korundu wykazały konkurencyjne właściwości żeliwa w stosunku do badanej stali. Ocena mikroskopowa oraz pomiary twardości i magnetyczne wykazały, że w warstwie wierzchniej żeliwa sferoidalnego ausferrytycznego zachodzi silne umocnienie spowodowane zgniotem, co skutkuje lepszymi niż dla stali wskaźnikami zużycia dla dużych obciążeń.
Austempered ductile iron is known for its excellent mechanical properties resulting from special phase composition and austempering heat treatment. Typical microstructure consists of ferrite plates of micrometre size submerged in untransformed austenite matrix. It has been recently shown that by use of appropriate chemical composition of cast iron and well targeted heat treatment parameters, it is possible to reduce ferrite plates width to submicron or even nanometric size. This creates the potential to achieve even higher mechanical properties of austempered ductile iron. The paper describes the influence of applied heat treatment parameters on microstructure of selected austempered ductile iron grades. Conditions necessary to reduce size of phases to a nanometric scale by heat treatment in austempered ductile iron are discussed.
The article presents the results of a comparative analysis of the metal substructure for dental prosthesis made from a Co-Cr-Mo-W alloy by two techniques, i.e. precision investment casting and selective laser melting (SLM). It was found that the roughness of the raw surface of the SLM sinter is higher than the roughness of the cast surface, which is compensated by the process of blast cleaning during metal preparation for the application of a layer of porcelain. Castings have a dendritic structure, while SLM sinters are characterized by a compact, fine-grain microstructure of the hardness higher by about 100 HV units. High performance and high costs of implementation the SLM technology are the cause to use it for the purpose of many dental manufacturers under outsourcing rules. The result is a reduction in manufacturing costs of the product associated with dental work time necessary to scan, designing and treatment of sinter compared with the time needed to develop a substructure in wax, absorption in the refractory mass, casting, sand blasting and finishing. As a result of market competition and low cost of materials, sinter costs decrease which brings the total costs related to the construction unit making using the traditional method of casting, at far less commitment of time and greater predictability and consistent sinter quality.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.