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.

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.

In this article, an attempt was made to determine the effect of dynamic load on the austempered ductile iron resistance obtained under different conditions of heat treatment. Tests were carried out on six types of cylindrical ductile iron samples austempered at 320, 370 and 400^oC for 30 and 180 minutes. For each type of material, two samples were collected. As a next step in the investigations, the samples were subjected to a Taylor impact test. The samples after striking a non-deformable, rigid target were deformed on their front face. After Taylor test, a series of material tests was performed on these samples, noting a significant increase of hardness in the deformed part. This was particularly well visible in the ductile iron isothermally quenched at higher temperatures of 370 and 400^oC. Inthezone of sample deformation, an increase in the content of ferromagnetic phase was also reported, thus indicating the occurrence of martensitic transformation in the microstructure containing mechanically unstable austenite. A significant amount of deformed graphite was also observed, which was a symptom of the deformation process taking place in samples. The ductile iron was characterized by high toughness and high resistance to the effect of dynamic loads, especially as regards the grade treated at a temperature of 370^oC.

Details var a2a_config = a2a_config || {}; a2a_config.onclick = 1; a2a_config.locale = "pl"; a2a_config.color_main = "D7E5ED"; a2a_config.color_border = "9D9D9D"; a2a_config.color_link_text = "ffffff"; a2a_config.color_link_text_hover = "ffffff"; a2a_config.color_bg = "d9d9d9"; a2a_config.icon_color = "#4e4e4e"; a2a_config.exclude_services = ["dihitt", "delicious", "whatsapp", "dzone", "sms", "stumpedia", "viber", "yahoo_messenger", "google_plus"]; Details PDF BIBTEX RIS Title Effect of Phenomena Accompanying Wear in Dry Corundum Abrasive on the Properties and Microstructure of Austempered Ductile Iron with Different Chemical Composition Journal title Archives of Metallurgy and Materials Yearbook 2015 Issue No 1 March Authors D. Myszka ; Wieczorek, A. Divisions of PAS Nauki Techniczne Publisher Institute of Metallurgy and Materials Science of Polish Academy of Sciences ; Committee of Materials Engineering and Metallurgy of Polish Academy of Sciences Date 2015[2015.01.01 AD - 2015.12.31 AD] Identifier DOI: 10.1515/amm-2015-0078 ; ISSN 1733-3490 Source Archives of Metallurgy and Materials; 2015; No 1 March References Shelton (2006), The effect of copper additions to the mechanical properties of austempered ductile iron of Materials Processing Technology, Journal, 173. ; Garin (2003), Strain - induced martensite In ADI alloys of Materials Processing Technology, Journal, 143. ; Dommarco (2004), Abrasion resistance of high nodule count ductile iron with different matrix mi - crostructures, Wear, 257. ; Pietrowski (1997), Ductile iron with microstructure of mixture of bainitic ferrite and austenite or bainite Archives of Materi - al Nauki o, Science, 18, 253. ; Chang (2006), Effects of heat treatment on the erosion behavior of austempered ductile irons, Wear, 260. ; Wieczorek (2014), The role of operational factors in shaping of wear properties of alloyed Austempered Ductile Iron Part Experimental studies abrasive wear of Austempered Ductile Iron in the presence of loose quartz abrasive of Metallurgy and Materials, Archives, 59. ; Narasimha Murthy (2009), Abrasion and erosion behaviour of manganese alloyed perma - nent moulded austempered ductile iron, Wear, 267.