Wyniki wyszukiwania - BazTech

1

Wpływ zawartości węgla i obróbki cieplnej na właściwości mechaniczne i mikrostrukturę stali niestopowej

Bolanowski K.

Obróbka Metalu

|

2015

|

nr 2

12--17

PL

Przedmiotem niniejszego opracowania jest stal niestopowa, której właściwości mechaniczne w wielu przypadkach są wystarczające w zastosowaniach technicznych. Właściwości mechaniczne stali można kształtować w dość dużym zakresie. Zakres możliwych zmian właściwości mechanicznych stali zależy od jej składu chemicznego, technologii wytwarzania, sposobu obróbki cieplnej itd.

EN

There are different grades of steel to suit the requirements of different industries. Their mechanical properties and microstructure are dependent both on the chemical composition as well as the forming and heat treatment processes applied. Of great importance is the content of carbon. The paper is divided into two parts. The part devoted to the mechanical properties of non-alloyed steel includes diagrams showing the influence of the carbon content on the hardness, tensile strength and elongation. The part concerned with the microstructure of nonalloyed steel includes images illustrating the effects of the carbon content and different processes on the formation of the microstructure of selected grades of non-alloyed steel.

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

|

2007

|

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

Struktury i odporność korozyjna modyfikowanych stopami aluminium pokryć cynkowych nastali niestopowej

Gałuszko M., Pękalski G., Godlejewski T.

Górnictwo Odkrywkowe

|

2007

|

R. 49, nr 3-4

57-62

PL

Na podstawie przeglądu literaturowego, dokonano modyfikacji zanurzeniowej powłoki cynkowej dwoma wybranymi stopami aluminium, tj. PA2 (ENWA-5251) i PA6 (ENAW-2017A), w celu podwyższenia jej odporności korozyjnej. Stopy te dodawano do wyjściowej kąpieli cynkowej w ilości 8%. Zwiększenie trwałości zanurzeniowej powłoki cynkowej jest szczególnie ważne dla jej zastosowań w środowiskach morskich i przemysłowych, w których ochronna warstwa czystego cynku ulega szybkiemu niszczeniu. Wzrost odporności korozyjnej klasycznej powłoki cynkowej uzyskuje się poprzez modyfikację jej składu chemicznego lub przez dodatkowe pokrywanie odpowiednio dobranymi zestawami powłok lakierowych (system Duplex). Odporność korozyjną modyfikowanych powłok badano w odniesieniu do wyjściowej powłoki cynkowej w komorach korozyjnych solnej i z atmosferą wilgotnego SO2. Dokonano także identyfikacji struktur uzyskanych powłok. Metodą potencjodynamiczną w roztworze 3% NaCl, a także w roztworze 3% Na2S04 wyznaczono prądy korozyjne określające odporność korozyjną badanych powłok. Stwierdzono, że najwyższą odporność korozyjną wykazała powłoka cynkowa modyfikowana stopem PA2.

EN

Using literature data the hot-dip zinc coating modification with the two select aluminum alloys PA2 (ENWA-5251) and PA6 (ENAW-2017A) was carried out to enhance its resistance to corrosion. The coating wear resistance is of particular importance for applications in hostile marine environment and industrial atmospheres where protective layer of pure zinc quickly wears out. The zinc coating protective quality can be enhanced by modification of its chemical composition or/ and by covering it with additional layer of paint (Duplex system). The initial concentration of PA 2 (ENWA-5251) and PA6 (ENAW-2017A alloys in zinc bath was 8 %. The corrosion was produced using corrosion chambers with salt spray and wet SO^ atmospheres and the corrosive wear of modified coatings was compared to the wear of the typical coating made of pure zinc. From the coatings 'structure and potentiodynamic investigations in 3 % NaCl and 3 % Na2S04 can be concluded that the highest protective quality has the zinc coating modified with PA2 alloy.

4

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

|

2007

|

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.