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Fabrication methods and heat treatment conditions effect on structure and properties of the gradient tool materials

Dobrzański L., Kloc-Ptaszna A., Pawlyta M., Pakieła W.

Archives of Materials Science and Engineering

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2012

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Vol. 56, nr 1

5-21

EN

Purpose: This work concerns manufacturing and research on a new group of the gradient tool materials, manufactured by the conventional powder metallurgy method, consisting in compacting a powder in a closed die and sintering it. Design/methodology/approach: The materials were obtained by mixing the powders of the HS6-5-2 high-speed steel, tungsten carbide (WC). The mixes were poured one after another into the die, yielding layers with the gradually changing volume ratio of carbides within the high-speed steel matrix. Structural research by using the scanning and transmission electron microscopes, x-ray microanalysis and density, hardness and porosity tests, were performed. Structure and hardness of selected materials after heat treatment were also investigated. The pin on plate test was used in order to examine the tribological properties of the analyzed materials. Findings: On the basis of the results of the research, it was found that it is possible to obtain gradient materials by the powder metallurgy methods, in order to ensure the required properties and structure of the designed material. It was shown that the new sintered graded materials are characterized by a multiphase structure, consisting of ferrite, primary carbides of the high speed steel, of the MC and M6C type, and dependently of the reinforcement phase, of the tungsten carbide WC which are introduced into the material, in the powder form. It has been proved by the pin on plate test that the addition of the tungsten carbide to the high-speed steel significantly improved the tribological properties. Practical implications: Developed material is tested for turning tools. Originality/value: The material presented in this paper has layers consisting of the carbide-steel with growing hardness on one side, and on the other side the high-speed steel, characterized by a high ductility.

2

The impact of production methods on the properties of gradient tool materials

Dobrzański L. A., Kloc-Ptaszna A., Matula G., Contreras J. M., Torralba J. M.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 24, nr 2

19-26

EN

Purpose: The goal of this work is to obtain the gradient materials based on the non-alloyed steel reinforced highspeed steel using the conventional powder metallurgy method and pressureless forming powder metallurgy. Design/methodology/approach: Forming methods were developed during the investigations for high-speed and unalloyed steel powders, making it possible to obtain materials with six layers in their structure. The non-alloyed steel was fabricated by mixing iron powders with graphite. Findings: It was found out, basing on the hardness tests, that the layer built of steel without any alloy elements demonstrates very low hardness in comparison with the transition layer and the HS6-5-2 high-speed layer. The density of the specimens rises with increasing temperature. It was also observed that porosity decreases along with the carbon content in these layers. Practical implications: It was noticed, that increase of the sintering temperature results in the uncontrolled growth and coagulation of the primary carbides and melting up to forming of eutectics in layers consisting of the high-speed steel. Developed material is tested for turning tools. Originality/value: The layers were poured in such way that the first layers consisted of the non-alloy steel and the last one from the high-speed steel, and were compacted next. The layers inside the material are mixes of the high-speed steel and non-alloy steel powders in the relevant proportions.

3

Structure and properties of the gradient tool materials of unalloyed steel matrix reinforced with HS6-5-2 high-speed steel

Dobrzański L. A., Kloc-Ptaszna A., Matula G., Torralba J. M.

Archives of Materials Science and Engineering

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2007

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Vol. 28, nr 4

197-202

EN

Purpose: The goal of this work is to obtain the gradient materials based on the non-alloyed steel reinforced highspeed steel using the pressureless formed method. Design/methodology/approach: The non-alloyed steel was fabricated by mixing iron powders with graphite. The unalloyed steel contains 0.5% carbon. The pressureless powder forming was used for manufacturing the materials. Findings: It was found out, basing on the hardness tests, that the layer built of steel without any alloy elements demonstrates very low hardness in comparison with the transition layer and the HS6-5-2 high-speed layer. It was also found, that the density rises with increasing temperature. The portion of pores in the particular layers of the gradient materials decreases along with the carbon concentration increase in particular layers. Practical implications: The material presented in this paper has layers, at one side consisting of the nonalloy steel with hardness growing with the increase of carbon content, and at other side the high-speed steel, characterized by a high ductility. Developed material is tested for turning tools. Originality/value: A forming methods were developed for high-speed and non-alloy steel powders, making it possible to obtain materials with three layers in their structure. Investigations included determining the sintering conditions, especially the temperature and treatment cycle, as well as examining selected mechanical properties.

4

Wpływ stężenia węgla na strukturę i własności gradientowych materiałów narzędziowych

Dobrzański L. A., Kloc-Ptaszna A., Matula G., Torralba J. M.

Archiwum Odlewnictwa

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2006

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R. 6, nr 21/1

141-148

PL

Celem niniejszej pracy jest opracowanie nowoczesnych materiałów gradientowych z wykorzystaniem konwencjonalnych metod metalurgii proszków, w celu zapewnienia wymaganych własności i struktury projektowanego materiału. Prezentowany materiał gradientowy posiada z jednej strony warstwę ze stali niestopowej, a z drugiej strony - warstwe ze stali szybkotnącej, charakteryzującej się dużą ciągliwością. Pomiędzy nimi znajdują sie warstwy przejściowe o wzrastającej zawartości węgla (twardości). Materiał taki testowany jest na noże tokarskie.

EN

The goal of this project is development of the contemporary gradient materials using the powder metallurgy methods to ensure the required properties and structure of the designed material. Material presented in this paper has layers consisting on one side from the non-alloy steel with hardness growing with the increase of carbon content, and on the other side the highspeed steel, characteristic of the high ductility. Such material is tested for turning tools.