Wyniki wyszukiwania - BazTech

1

Regularities of Spheroidization of HMX Extracted from Solid Propellant Disposal Products

Cheltonov Maksym, Zakusylo Roman, Ustymenko Ievhen

Central European Journal of Energetic Materials

|

2020

|

Vol. 17, no. 4

523--534

EN

Nitramines of high quality for manufacturing high-energy composites, such as oсtogen (HMX) and hexogen, have received much attention by researchers worldwide. Mixed formulations containing fillers in the form of spheroidal dispersed particles of explosives are homogenized at lower energy consumption. They are characterized by stable rheological characteristics, which guarantee the quality of the products obtained on the basis thereof. Methods for obtaining spherical nitramine particles by means of ultrasonic and hydromechanical rounding using commercial HMX were evaluated. It was found that under similar conditions, rounding by the hydromechanical process in a vortex device is more efficient and less energy-consuming than that of the ultrasonic method. It was confirmed that spheroidization of commercial HMX in an aqueous dimethyl sulfoxide (DMSO) medium by hydromechanical rounding occurs due to erosion of crystals of large size (70 μm or more). Based on the experimental results with spheroidization of commercial nitramine, the mass fraction content below 50 μm versus time was plotted for hydromechanical rounding. The method of hydromechanical rounding in aqueous DMSO to obtain spheroidized HMX, extracted from solid propellant using DMSO, was found to be the most suitable. Spheroidized modified HMX with specific characteristics (density and crystals of near-spherical shape) was obtained, which could be used for the manufacture of high-energy composites.

2

Thermal range of cementite occurrence in hypereutectoid alloys with controlled C, Cr and Mn content

Frocisz Ł., Krawczyk J., Kozieł T., Górecki K., Tokarski T., Kopuściański M., Matusiewicz P.

Inżynieria Materiałowa

|

2018

|

Vol. 39, nr 1

29--33

EN

The hypereutectoid alloys are the commonly used for the tool manufacturing. The high carbon content prevent the high hardenability and presence of the secondary cementite precipitation in microstructure. High hardness of such materials provide the good wear resistance required for tool materials. New hypereutectoid alloys designed for the investigations of secondary cementite precipitations influence on wear resistance have been investigated. Materials were prepared by the use of the ArcMelter furnace. After the plastic deformation materials were annealed at 700°C by 12 h to homogenize the microstructure. After the annealing the calorymetry and dilatometry research were performed. The following research allow authors to state that the increase of the carbon content resulted in the change of ACCM temperature. To obtain the most similar properties of the matrix investigated materials were alloyed by the addition of Cr and Mn. It was confirmed by the same temperature range of the eutectoid transformation for each material. Additionally the influence of Mn and Cr on cementite dissolution process was observed.

PL

Stale nadeutektoidalne charakteryzują się dużą zawartością węgla przekraczającą wartość dla punktu eutektoidalnego. Skutkuje to obecnością w ich mikrostrukturze cementytu drugorzędowego wydzielonego z austenitu podczas chłodzenia. Cementyt ten w znaczący sposób zmienia właściwości mechaniczne materiału, przy czym same właściwości cementytu silnie zależą od składu chemicznego. Dodatki Mn i Cr w znaczący sposób zwiększają jego twardość i stabilność termiczną. Węglik ten, a zwłaszcza jego morfologia, wpływa również na mechanizm zużycia elementów ze stali nadeutektoidalnych. W pracy zaprezentowano analizę występowania cementytu stopowego podczas nagrzewania w nowo zaprojektowanych stalach nadeutektoidalnych z kontrolowaną, ściśle założoną różnicą w zawartości C, Mn i Cr.

3

The Structural and Strength Changes Resulting from Modification of Heat Treatment of High Carbon Steel

Grygier D., Rutkowska-Gorczyca M., Jasiński R., Dudziński W.

Archives of Metallurgy and Materials

|

2016

|

Vol. 61, iss. 2B

971--976

EN

Pearlitic steels containing from some 0,8 to 0,95% C belong to the group of unalloyed steels intended for cold drawing or rolling. One of the problems discussed in literature is cracking of pearlitic steel subjected to plastic working, caused by high brittleness of the lamellar precipitations of hard cementite. This issue is extremely important because it affects significantly reduce fatigue strength. The paper presents proposals to modify the process of heat treatment, results in getting a steel with spheroidal structure characterized by better plastic properties, in order to eliminate this problem.

4

Investigations of Ferritic Nodular Cast Iron Containing About 5-6% Aluminium

Soiński M. S., Kordas P., Skurka K., Jakubus A.

Archives of Foundry Engineering

|

2016

|

Vol. 16, iss. 4

141--146

EN

The work presents results of investigations concerning the production of cast iron containing about 5-6% aluminium, with the ferritic matrix in the as-cast state and nodular or vermicular graphite precipitates. The examined cast iron came from six melts produced under the laboratory conditions. It contained aluminium in the amount of 5.15% to 6.02% (carbon in the amount of 2.41% to 2.87%, silicon in the amount of 4.50% to 5.30%, and manganese in the amount of 0.12% to 0.14%). After its treatment with cerium mixture and graphitization with ferrosilicon (75% Si), only nodular and vermicular graphite precipitates were achieved in the examined cast iron. Moreover, it is possible to achieve the alloy of pure ferritic matrix, even after the spheroidizing treatment, when both the aluminium and the silicon occur in cast iron in amounts of about 5.2÷5.3%.

5

Application of the Digital Material Representation to strain localization prediction in the two phase titanium alloys for aerospace applications

Muszka K., Madej L., Wynne B. P.

Archives of Civil and Mechanical Engineering

|

2016

|

Vol. 16, no. 2

224--234

EN

In the present work Digital Material Representation (DMR) approach was utilized to simulate the deformation behavior of the two phase Ti-6Al-4V alloy. DMR models of the two phase structure, containing different morphologies of alpha grains within a beta matrix – lamellar and equiaxed, were created. Each phase was then separated and different mechanical properties were assigned. Subsequently, their response to loading was tested using simple shear numerical simulations with special focus on strain inhomogeneities, as the main driving force for spheroidization is considered to be the formation of intense shearing within alpha lamellae. The proposed modeling approach combining Finite Element Method (FEM) with DMR allowed for much more detailed numerical analysis of deformation behavior of two phase titanium alloys at the micro scale and provided information such as strain localization and stress distributions within the alpha and beta phases. It was showed that presented model offers a new and powerful tool to study the physical bases of microstructure evolution processes such as spheroidization or recrystallization of Ti alloys. It shows good potential in simulation of deformation processes of complex two-phase morphologies that is a crucial step towards optimization of process parameters during hot forming of Ti-6Al-4V alloys.

6

Characteristics of Graphite Precipitates in Aluminium Cast Iron Treated with Cerium Mixture

Soiński M. S., Jakubus A., Kordas P., Skurka K.

Archives of Foundry Engineering

|

2015

|

Vol. 15, iss. 1

93--98

EN

The work determined the influence of aluminium in the amount from about 1% to about 7% on the graphite precipitates in cast iron with relatively high silicon content (3.4% to 3.90%) and low manganese content (about 0.1%). The cast iron was spheroidized with cerium mixture and graphitized with ferrosilicon. The performed treatment resulted in occurring of compact graphite precipitates, mainly nodular and vermicular, of various size. The following parameters were determined: the area percentage occupied by graphite, perimeters of graphite precipitates per unit area, and the number of graphite precipitates per unit area. The examinations were performed by means of computer image analyser, taking into account four classes of shape factor. It was found that as the aluminium content in cast iron increases from about 1.1% to about 3.4%, the number of graphite precipitates rises from about 700 to about 1000 per square mm. For higher Al content (4.2% to 6.8%) this number falls within the range of 1300 – 1500 precipitates/mm2. The degree of cast iron spheroidization increases with an increase in aluminium content within the examined range, though when Al content exceeds about 2.8%, the area occupied by graphite decreases. The average size of graphite precipitates is equal to 11-15 μm in cast iron containing aluminium in the quantity from about 1.1% to about 3.4%, and for higher Al content it decreases to about 6 μm.

7

Badanie czynników zmieniających stan fizykochemiczny ciekłego żeliwa i wybrane właściwości tworzywa

Kuder M.

Prace Instytutu Odlewnictwa

|

2013

|

T. 53, z. 2

13--28

PL

Badania przeprowadzono w kierunku określenia wpływu sposobu sferoidyzacji i modyfikacji, wartości CE, zawartości magnezu i lantanu na skłonność do tworzenia wad typu skurczowego, struktury i właściwości wytrzymałościowych żeliwa sferoidalnego na cienkościenne odlewy. Stwierdzono, że żeliwo jest w zakresie 4–25 mm czułe na grubość ścianki, szczególnie przy zbyt niskich stężeniach magnezu. Najbardziej efektywnym modyfikatorem okazał się stop z zawartością baru. Nie stwierdzono znaczącego wpływu lantanu na właściwości żeliwa, wprowadzanego w zaprawie sferoidyzującej, jak i w modyfikatorze.

EN

The study was conducted to determine the effect of spheroidization and modification method, of the CE value, the content of magnesium and lanthanum on susceptibility to form shrinkage defects, structure and resistance properties of ductile cast iron on thin-walled castings. It was stated that cast iron in the range 4–25 mm is sensitive to wall thickness, especially at very low concentrations of magnesium. It turned out that the most effective modifier was the alloy with barium content. There was no significant effect of lanthanum on the properties of cast iron introduced in spheroidizing mortar as well as in the modifier.

8

The influence of small amounts of aluminium on the effectiveness of cast iron spheroidization with magnesium

Soiński M. S., Jakubus A.

Archives of Foundry Engineering

|

2013

|

Vol. 13, iss. 3

80--83

EN

The influence of aluminium added in amounts of about 1.6%, 2.1%, or 2.8% on the effectiveness of cast iron spheroidization with magnesium was determined. The cast iron was melted and treated with FeSiMg7 master alloy under industrial conditions. The metallographic examinations were performed for the separately cast rods of 20 mm diameter. They included the assessment of the shape of graphite precipitates and of the matrix structure. The results allowed to state that the despheroidizing influence of aluminium (introduced in the above mentioned quantities) is the stronger, the higher is the aluminium content in the alloy. The results of examinations carried out by means of a computer image analyser enabled the quantitative assessment of the considered aluminium addition influence. It was found that the despheroidizing influence of aluminium (up to about 2.8%) yields the crystallization of either the deformed nodular graphite precipitates or vermicular graphite precipitates. None of the examined specimens, however, contained the flake graphite precipitates. The results of examinations confirmed the already known opinion that aluminium widens the range of ferrite crystallization.

9

The Influence of Aluminium on the Spheroidization of Cast Iron Assessed on the Basis of Wedge Test

Soiński M. S., Jakubus A., Stradomski G.

Archives of Foundry Engineering

|

2013

|

Vol. 13, iss. 1 spec.

163--168

EN

The paper discusses the influence of aluminium in quantities from about 1.9% to about 4.7% on both the alloy matrix and the shape of graphite precipitates in cast iron spheroidized with cerium mixture (added in the quantity of 0.11%) and inoculated with ferrosilicon (1.29%). The metallographic examinations were carried out for specimens cut out of the wedge test castings (22 mm base width, 120 mm height, 180 mm length) halfway along their length. It was found that the highest susceptibility to graphitization exhibits the cast iron containing about 2.8% Al. The alloy matrices were classified and the degrees of graphite spheroidization were determined. Microscopic observations were carried out along the wedge test casting height at several places, the first distant by 20 mm from the specimen apex, the next ones every 20 mm farther. Precipitates of nodular and vermicular graphite were found in the cast iron structure. The results of examination allow to state that cast iron spheroidized in the way described here is characterised by the degree of spheroidization which increase with an increase in aluminium content within the examined range.

10

Badania procesów sferoidyzacji plazmowej mieszanek proszkowych W-Re-Ni i W-Re-Ni-Fe

Majewski T., Dębski A.

Inżynieria Materiałowa

|

2012

|

Vol. 33, nr 5

464--468

PL

W pracy przedstawiono wybrane wyniki badań dotyczących sferoidyzacji plazmowej mieszanek proszkowych W-Re-Ni oraz W-Re-Ni-Fe. Proszki wytworzone w ten sposób charakteryzują się m.in bardzo dobrą zagęszczalnością, co może w konsekwencji poprawić właściwości gotowego spieku. Przewiduje się, że materiały te mogą znaleźć zastosowanie w produkcji rdzeni pocisków przeciwpancernych, a także wysokoprądowych styków elek- trycznych. Przedstawiono schemat procesu otrzymywania sferoidyzowanych mieszanek proszkowych (rys. 1). Sferoidyzacja była realizowana z wykorzystaniem stanowiska do natryskiwania plazmowego, w komorze wypełnionej gazem obojętnym. W artykule zamieszczono zdjęcia mieszanek plazmowych przed modyfikacją i po niej, które pokazują zmiany wielkości i kształtu cząstek proszków zachodzące w trakcie procesu sferoidyzacji (rys. 3 i 4). Pokazano również odpowiadające tym stadiom rozkłady granulometryczne. Wyniki badań wskazują, że w rezultacie modyfikacji otrzymano cząstki o kształcie sferycznym oraz nastąpiło zwiększenie ich średnicy. Warunki prowadzenia tego procesu spowodowały, że nastąpiło utlenienie proszków, dlatego w końcowej fazie produkcji należało je poddać redukcji. Wykazano, że temperatura 900°C jest wystarczająca dla uzyskania pełnej redukcji tlenków w badanych mieszankach proszkowych (rys. 6, tab. 1). W pracy przedstawiono również wy niki badań naprężeń wewnętrznych w cząstkach proszków (rys. 7), które pozwoliły stwierdzić, że modyfikacja w strumieniu plazmy jest przyczyną znacznego wzrostu naprężeń w porównaniu z tymi, jakie występują po długotrwałym mieszaniu w mieszalniku kulowym. Takie „uaktywnienie” proszków może umożliwić intensyfikację procesów dyfuzji w trakcie wytwarzania spieku, a przez to możliwość obniżenia temperatury lub skrócenia czasu operacji spiekania.

EN

Selected measurement results of plasma spheroidization used for W-Re-Ni and W-Re-Ni-Fe powder mixtures are presented in the paper. Powders produced in this way have a very good compressibility which, in turn, can improve final sinter properties. One can expect that those materials can be used for production of armour-piercing kinetic energy penetrators or high-current contacts. The scheme for production process of the spheroidized powder mixtures is presented (Fig. 1). The spheroidization was carried out on the stand for plasma spraying in the chamber filled with neutral gas. The pictures of plasma mixtures before and after modification, which show changes in size and shape of powder particles, as well as corresponding to these mixture types size distributions are also presented in the paper (Fig. 3 and 4). Measurement results show that after modification powder particles are of spherical shape and their diameters increase. The conditions of the spheroidization process led to powder oxidation and that is why in the final production stage the powders were subjected to reduction. It was demonstrated that temperature of 900°C is sufficient for complete oxide reduction in the tested powder mixtures (Fig. 1, Tab. 1). Test results of internal stresses in powder particles revealed that exactly modification in plasma jest is responsible for significant growth of these stresses, compared to stresses after long-term mixing in a ball mixer (Fig. 7). Such “activation” of powder can intensify diffusion processes during powder production thus giving a chance to lower temperature or shorten sintering process.

11

The influence of small amounts of aluminium on the spheroidization of cast iron with cerium mischmetal

Soiński M. S.

Archives of Foundry Engineering

|

2012

|

Vol. 12, iss. 2

117-122

EN

The influence of aluminium (added in quantity from about 0.6% to about 2.8%) on both the alloy matrix and the shape of graphite precipitates in cast iron treated with a fixed amounts of cerium mischmetal (0.11%) and ferrosilicon (1.29%) is discussed in the paper. The metallographic examinations were carried out for specimens cut out of the separately cast rods of 20 mm diameter. It was found that the addition of aluminium in the amounts from about 0.6% to about 1.1% to the cast iron containing about 3% of carbon, about 3.7% of silicon (after graphitizing modification), and 0.1% of manganese leads to the occurrence of the ferrite-pearlite matrix containing cementite precipitates in the case of the treatment of the alloy with cerium mischmetal . The increase in the quantity of aluminium up to about 1.9% or up to about 2.8% results either in purely ferrite matrix in this first case or in ferrite matrix containing small amounts of pearlite in the latter one. Nodular graphite precipitates occurred only in cast iron containing 1.9% or 2.8% of aluminium, and the greater aluminium content resulted in the higher degree of graphite spheroidization. The noticeable amount of vermicular graphite precipitates accompanied the nodular graphite.

12

Abrasive wear resistance of cast iron with precipitates of spheroidal VC carbides

Kawalec M., Olejnik E.

Archives of Foundry Engineering

|

2012

|

Vol. 12, iss. 2

221-226

EN

The paper presents the results of abrasive wear resistance tests carried out on high-vanadium cast iron with spheroidal VC carbides. The cast iron of eutectic composition was subjected to spheroidising treatment using magnesium master alloy. The tribological properties were examined for the base cast iron (W), for the cast iron subjected to spheroidising treatment (S) and for the abrasion-resistant steel (SH). Studies have shown that high-vanadium cast iron with both eutectic carbides and spheroidal carbides has the abrasion resistance twice as high as the abrasion-resistant cast steel. The spheroidisation of VC carbides did not change the abrasion resistance compared to the base high-vanadium grade.

13

A Comparison of Selected Methods of Graphitizing Inoculation Applied after the Spheroidizing Treatment

Gunia P., Soiński M.

Archives of Foundry Engineering

|

2012

|

Vol. 12, iss. 2s

95--99

EN

The work compares the effectiveness of selected methods of graphitizing inoculation applied after the spheroidization in the slender tundish ladle of 1 Mg capacity. The inoculation was carried out according to the three various options. The first one was performed simply by means of the block of inoculant inserted in the gating system of the mould, the second one started with initial inoculation by the in-stream method during the transfer of metal from the slender ladle to the pouring ladle and was completed with the secondary modification by means of the inoculant insert placed in the mould, the third one consisted in similar initial inoculation by the in-stream method during the transfer of metal from the slender ladle to the pouring ladle followed by the secondary inoculation, again by the in-stream method, applied during the pouring operation. Examination of cast iron structure allowed to find that the best results of inoculation are achieved in the case of inoculation carried out according to the Option III, though in all cases it was possible to produce cast iron of EN-GJS-400-15 grade meeting the demands of the Standard.

14

Badanie procesów modyfikacji plazmowej proszków W i Re oraz mieszanek W-Re

Majewski T.

Biuletyn Wojskowej Akademii Technicznej

|

2011

|

Vol. 60, nr 2

331-337

PL

W artykule przedstawiono wybrane wyniki badań sferoidyzacji plazmowej proszków wolframu i renu oraz mieszanki proszkowej sporządzonej z tych metali. Wymienione materiały mogą być użyte w produkcji spieków przeznaczonych na rdzenie pocisków przeciwpancernych. Sferoidyzację wymienionych proszków wykonano przy zastosowaniu stanowiska do natryskiwania plazmowego, w komorze wypełnionej gazem obojętnym. Przedstawiono zmiany wielkości i kształtu cząstek proszków zachodzące w procesie sferoidyzacji, a także wyniki badań naprężeń wewnętrznych w cząstkach proszków.

EN

Many methods for modification of shape and properties of powder particles are used in powder metallurgy. They are devoted to improvement in characteristics of a final product - the sinter. One of the methods is powder spheroidization in plasma jet which gives the following effects: the powder is characterized by high compressibility and good technical properties while particle roughness and cracks can be eliminated, and so on. Selected results of plasma spheroidization of tungsten and rhenium sinters intended for production of penetrators and high-current contacts are presented in the paper. The spheroidization of the above-mentioned powders was performed on the stand for plasma spraying in a chamber filled with neutral gas. In the paper, the pictures of tungsten, rhenium and mixed W-Re powder particles before and after spheroidization are presented. Grain size analysis of the produced powders was carried out and tests of their other properties were also performed. Exemplary grain size distributions of tungsten powder particles before and after plasma spheroidization are presented Presented results show that powders with spherical particles can be produced using device for plasma spraying. This process increases particle size for powders with fine granulation – in our case for tungsten powders. Increase in particle size for powders with larger granulation is weaker. The internal stress level in powder particles can be enhanced due to plasma spheroidization and in some cases this rise is larger than for mechanical mixing or size reducing.

15

Cast iron spheroidization by plunging method and cored wire method

Soiński M. S., Wachowski A.

Archives of Foundry Engineering

|

2009

|

Vol. 9, iss. 1

199-202

EN

Changes in chemical composition and the degree of magnesium assimilation resulting from the performed treatment have been determined basing on data coming from 185 courses of cast iron treatment by plunging or cored wire methods. The investigations have dealt with nodular iron of EN-GJS-400-18-LT and EN-GJS-500-7 grades. In the case of plunging method cast iron has been treated with VL53M master alloy containing about 9% of magnesium; for cored wire method the magnesium content in the master alloy has been about 17%. It has been stated, among others, that the carbon content has been reduced due to spheroidizing treatment by 0.12-0.30% as an average. Distinctly higher magnesium assimilation (at the level of 41-44%) has been stated for plunging method, while for cored wire method it has been found to vary from 29% to 31% as an average.

16

The low-aluminium cast iron of reduced silicon content treated with cerium mischmetal

Soiński M. S., Susek P., Hübner K., Mierzwa P.

Archives of Foundry Engineering

|

2008

|

Vol. 8, iss. 2

123-128

EN

The work presents the effect of cerium mischmetal used in quantities of 0.1 and 0.2 wt-% and ferrosilicon used in quantities from 0.5% to 1.5% on the alloy matrix and the shape of graphite precipitates in the low-aluminium cast iron from seven heats, basing on the examination of its structure. The hypereutectic cast iron of the relatively high carbon content (4.0÷4.2%) at the prior-to-treatment silicon and manganese content equal to ca. 0.6% and ca. 0.04%, respectively, has been examined. It has been found that the performed treatment leads to the change in the alloy matrix from the nearly almost pearlitic to the ferritic-pearlitic one accompanied by changes in the shape of graphite precipitates. Due to applying both of the mentioned substances in the above stated amounts the graphite precipitates in cast iron have taken the shape of nodular and vermicular ones, and no presence of flake graphite has been revealed. A quantitative analysis of the performed treatment i.e. determining the fractions of graphite precipitates of different shapes has been possible by means of a computer image analyser.

17

Influence of orientation relationship between ferrite and cementite in pearlite on stability of cementite plates

Czarski A., Skowronek T., Osuch W.

Metallurgy and Foundry Engineering

|

2007

|

Vol. 33, no. 1

41-49

EN

The aim of the studies performed was to assess an influence of crystallographic orientation relationship (OR) between pearlitic ferrite and cementite on a stability of cementite plates. Diffraction analysis made with an electron microscope showed the existence of the Bagaryatski OR and the Pitsch OR both in the pearlite structure after eutectoid transformation and after each tested time of the sphe-roidization annealing. The obtained results indicate that the crystallographic orientation relationship does not influence the stability of cementite showing lamellar morphology.

PL

Celem przeprowadzonych badań była ocena wpływu orientacji krystalograficznej faz perlitu w stali na stabilność płytek cementytu. Analiza dyfrakcyjna wykonana za pomocą mikroskopu elektronowego wykazała występowanie relacji orientacji krystalograficznych Bagariackicgo oraz Pitscha zarówno w strukturze perlitu po przemianie eutektoidalnej, jak i po każdym badanym etapie wyżarzania sferoidyzującego. Otrzymane wyniki badań dyfrakcyjnych wskazują, że na stabilność cementytu wykazującego morfologie płytkową nic wpływa orientacja krystalograficzna cementytu i ferrytu w strukturze wyjściowej.

18

Krótkotrwała ultrawysokotemperaturowa sferoidyzacyjna obróbka cieplna siluminów

Czekaj E., Fajkiel A., Gazda A.

Archiwum Odlewnictwa

|

2005

|

R. 5, nr 17

51--68

PL

Siluminy należą do najczęściej stosowanych stopów na osnowie aluminium przetwarzanych poprzez odlewanie. Ich podstawowym wadą, w porównaniu z innymi tworzywami konstrukcyjnymi, jest niedostateczny zapas plastyczności, a zatem ograniczone możliwości eksploatacyjne pod względem odporności na pękanie przy statycznym obciążeniu rozciągającym czy zmęczeniu cieplno-mechanicznym. W celu poprawy charakterystyk plastyczności siluminów dokonywane są różnorodne zabiegi technologiczne tak na ciekłym metalu, w procesach odlewania, jak też po skrzepnięciu stopu. Jednym ze sposobów polepszania wydłużenia siluminów jest zastosowanie specjalnych metod obróbki cieplnej. W ostatnim okresie pojawiły się w zagranicznej, specjalistycznej literaturze prace dotyczące prób sferoidyzacji krzemu eutektycznego poprzez zastosowanie krótkotrwałej wysokotemperaturowej obróbki cieplnej sięgającej – a nawet przewyższającej – próg początkowy topnienia siluminów typu A356, A357 (dawny polski stop AK7 – wg nie obowiązującej już normy PN-76/H-88027, czy AlSi7Mg {EN AC-42000…42200} – zgodnie z PN-EN 1706). Wynikiem tych zabiegów jest znacząca poprawa plastyczności, przy jednoczesnym zwiększeniu parametrów wytrzymałościowych. Dodatkowym ważnym aspektem proponowanej odmiany obróbki cieplnej jest pozytywny efekt ekonomiczny.

EN

Silumins belong to the family of aluminium-based alloys most often processed by the casting process. Their main drawback, compared with other engineering materials, is low toughness, and hence reduced possibilities of their use because of crack formation under the static tensile loads or thermal-mechanical fatigue. To improve the toughness of the silumins, various technological treatments are performed on molten metal, during casting, or after alloy solidification. One of the means for improving the elongation of silumins is through application of special heat treatment. During the last period, some publications appeared in the technical foreign literature on attempts at obtaining the spherodidization of eutectic silicon by short-lived ultra high temperature heat treatment, reaching - or exceeding even - the lower melting point of silumins of the type A356, A357 (former Polish designation AK7 according to PN-76/H-88027 invalid now, or AlSi7Mg {EN AC-42000 ...42200) according to PN-EN 1706). An output of this treatment is considerable improvement of toughness accompanied by increased mechanical parameters. Another important aspect of the proposed variation of heat treatment are advantages of purely economic nature. The text presented below is a fragment of more comprehensive study made at the Foundry Research Institute in Cracow in year 2004 within the framework of statutory activity of the Institute (no. 3002/00) under the title: "Attempts at spheroidizing the hypo- and eutectic silumins" [1].

19

Ogólna ocena metody PE sferoidyzowania żeliwa

Guzik E.

Archiwum Odlewnictwa

|

2001

|

R. 1, nr 1

83--91

PL

W pracy przedstawiono metodę zabiegu sferoidyzowania żeliwa o masie od 1 do 10 Mg przy użyciu specjalnego przewodu elastycznego, zwaną umownie w kraju jako technika PE. Technikę tę zastosowano dla żeliwa wytapianego w żeliwiaku bądź w piecach indukcyjnych. Ustalono zużycie tego przewodu w zależności od zawartości siarki w żeliwie wyjściowym i masy sferoidyzowanego żeliwa. Niewątpliwie, odlewnie mają określone problemy związane z zabiegiem ulepszającym ciekłe żeliwo, a technika PE jest optymalna i coraz częściej adaptowana w krajowych odlewniach.

EN

This paper describes the results of using a high magnesium ferrosilicon alloy in cored wire ( Mg recovery about 60% ) for the production nodular ( or vermicular) iron castings (ladles with a capacity from 1,0 to 10 Mg) at Polish foundries. The injection of Mg cored wire length is a treatment method which can be used to process (high sulphur) cupola iron held in ladles or friquency induction furnace. Results of calculation and experiments shows the amount of cored wire to be injected based on initial sulfur and weight liquid cast iron levels. The results of numerous trials have shown that process magnesium cored wire is capable of producing good quality castings with nodular or vermicular graphite iron. Such foundries have traditionally found it difficult to produce nodular or vermilular cast iron of acceptable quality and thus the adoption of cored wire technology has enabled these foundries to enter the ductile iron and vermicular cast iron market.

20

Wpływ sposobu sferoidyzacji odlewów dla motoryzacji na ich jakość oraz kształtowanie kosztów produkcji

Krzemień E., Sitko J., Dubas K.

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

|

2000

|

z. 1

41-53

PL

Artykuł prezentuje poszukiwanie i sprecyzowanie przyczyn występowania niejednolitego poziomu jakości wyrobów z żeliwa sferoidalnego o różnej grubości ścianek produkowanych w odlewni. Ponadto przedstawia wpływ zmian parametrów procesu (rodzaju i szybkości podawania sferoidyzatora i modyfikatora) na zmiany właściwości wyrobów oraz przesłanki zastosowania nowej technologu wytwarzania żeliwa sferoidalnego. Końcowym zagadnieniem artykułu jest prezentacja kosztów wytwarzania wyrobów różnymi technologiami.

EN

The article presents process of researches and specification of reasons of appearance the various quality level of goods from spheroid cost iron with different sides thickness. Moreover the article shows the influence of parameters of process changes (changes of kind and giving spheroid and modifier speed) for good peculiarity changes and it introduces premises of spheroid cost iron production new technology application.