Wyniki wyszukiwania - Biblioteka Nauki

1

Evaluation of metallurgical quality of master heat IN-713C nickel alloy ingots

100%

Binczyk F. , Cwajna J. , Roskosz S. , Gradoń P.

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tom Vol. 12, iss. 4

5-10

EN

The paper presents the results of evaluation of the metallurgical quality of master heat ingots and of the identification of non-metallic inclusions (oxides of Al., Zr, Hf, Cr, etc.), which have been found in the shrinkage cavities formed in these ingots. The inclusions penetrate into the liquid alloy, and on pouring of mould are transferred to the casting, especially when the filtering system is not sufficiently effective. The specific nature of the melting process of nickel and cobalt alloys, carried out in vacuum induction furnaces, excludes the possibility of alloy refining and slag removal from the melt surface. Therefore, to improve the quality of castings (parts of aircraft engines), it is so important to evaluate the quality of ingots before charging them into the crucible of an induction furnace. It has been proved that one of the methods for rapid quality evaluation is an ATD analysis of the sample solidification process, where samples are taken from different areas of the master heat ingot. The evaluation is based on a set of parameters plotted on the graph of the dT/dt derivative curve during the last stage of the solidification process in a range from TEut to Tsol.

2

Wpływ parametrów obróbki cieplnej na kształtowanie mikrostruktury żeliwa ADI

100%

Furmanek J. , Binczyk F. , Gradoń P.

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tom T. 62, nr 4

5-14

PL

W pracy przedstawiono wyniki badań mikrostruktury żeliwa sferoidalnego w stanie odlanym oraz po dwustopniowej obróbce cieplnej (austenityzacja w 900°C i wygrzewanie izotermiczne w 280, 330 i 380°C). Za pomocą programu komputerowego LUCIA oceniono cechy morfologii grafitu oraz osnowy metalowej. Metodą spektroskopii Mössbauera dokonano oceny składu osnowy żeliwa ADI, co umożliwiło określenie udziału austenitu wykazującego właściwości paramagnetyczne. Wyniki tych pomiarów, w połączeniu z wynikami badań kalorymetrycznych pozwoliły na dokonanie opisu procesów przebiegających podczas wygrzewania izotermicznego. Na wykresach kalorymetrycznych podczas nagrzewania żeliwa ADI stwierdzono obecność silnego efektu egzotermicznego, którego początek przemieszcza się od 468°C do 489°C w miarę podwyższania temperatury wygrzewania izotermicznego. Wartość entalpii tego efektu zmienia się proporcjonalnie do zmiany udziału austenitu w żeliwie skutkiem obróbki cieplnej. Na tej podstawie stwierdzono, że proces powstawania osnowy żeliwa, składającej się z ferrytu i stabilnego, przesyconego węglem austenitu, ma charakter endotermiczny i wymaga dostarczenia energii do układu.

EN

This paper gives the results of microstructure investigations of ductile cast iron in as-cast condition and after two-stage heat treatment (austenitisation at 900°C and isothermal soaking at 280, 330 and 380oC). The morphological features of graphite and metallic matrix were determined using LUCIA software. The Mössbauer spectroscopy method was used to determine the composition of ADI cast iron matrix, which enabled the determination of the share of austenite which demonstrated paramagnetic properties. In combination with the results of calorimetric investigations, the results of these measurements enabled the processes occurring during isothermal soaking to be described. While heating ADI cast iron, the presence of strong exothermal effect, the beginning of which transferred from 468°C to 489°C as the isothermal soaking temperature was increasing, was found on calorimetric diagrams. The enthalpy value of this effect changes in proportion to the change in the share of austenite in cast iron as a result of heat treatment. Based on that, it was found that formation of cast iron matrix consisting of ferrite and stable carbon supersaturated austenite is of endothermic nature and requires the supply of energy to the system.

3

Influence of Modification and Casting Technology on Structure of IN-713C Superalloy Castings

100%

Gradoń P. , Binczyk F. , Mańka M. , Cwajna J.

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nr 3

4

Modification of macrostructure of nickel superalloys with cobalt nanoparticles

100%

Binczyk F. , Śleziona J. , Gradoń P.

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tom R. 11, nr 1

49-54

EN

The paper presents the results of studies on the effect of combined surface and bulk modifications on the macrostructure of castings made from remelted, post-production IN-713C, IN-100 and MAR-247 waste alloys. Surface modification was carried out by applying onto the wax pattern surface, a coating containing zirconium silicate and cobalt aluminate. Bulk modification was carried out when the cast liquid alloy was passed through a special ceramic filter containing, among others, cobalt aluminate. The nanoparticles of cobalt, acting as crystallisation nuclei, are the product of a modifier reaction (CoAl2O4 inoculant) with the chemically active constituents of the nickel alloys and with the additional filter components in the form of Al and Ti powders. The filters were placed in the mould pouring basin. The beneficial effect of combined modification on the macrostructure (equiaxial crystals) and mechanical properties was stated. The effect of the active constituents present in the nickel alloys and in the filter material was confirmed. A particularly strong refining effect on the macrostructure of equiaxial crystals was obtained in the MAR-247 alloy, which contained the strongest chemically active additives of Hf, Ta and Nb. A hypothetical model of the surface and bulk modification was developed. A strong influence of the alloy pouring temperature on the modification effect was reported. Modification was most effective when the pouring temperature did not exceed 1440°C.

PL

Zamieszczono wyniki badań wpływu łącznego modyfikowania powierzchniowego i objętościowego na makrostrukturę odlewów wykonanych po przetopie odpadów poprodukcyjnych ze stopów IN-713C, IN-100 i MAR-247. Modyfikację powierzchniową zrealizowano poprzez naniesienie na model woskowy powłoki zawierającej krzemian cyrkonu i glinian kobaltu. Modyfikację objętościową zrealizowano podczas odlewania ciekłego stopu przez specjalne filtry ceramiczne, zawierające między innymi glinian kobaltu. Nanocząstki kobaltu, pełniące rolę zarodków krystalizacji, są produktem reakcji modyfikatora (inoculant CoAl2O4) z aktywnymi chemicznie składnikami stopów niklu oraz dodatkowymi składnikami filtrów w postaci proszków Al i Ti. Filtry umieszczono w zbiorniku wlewowym formy. Stwierdzono korzystny wpływ łączonej modyfikacji na makrostrukturę (kryształy równoosiowe) i właściwości mechaniczne. Potwierdzono oddziaływanie aktywnych składników obecnych w stopach niklu i materiale filtrów. Szczególnie silny efekt rozdrobnienia makrostruktury kryształów równoosiowych uzyskano dla stopu MAR-247, który zawiera najbardziej aktywne chemicznie dodatki Hf, Ta i Nb. Opracowano hipotetyczny model modyfikacji powierzchniowej i objętościowej. Stwierdzono istotny wpływ temperatury odlewania stopu na efekt modyfikowania. Efekt modyfikowania jest szczególnie widoczny przy temperaturze odlewania poniżej 1440°C.

5

The Relationship Between the Solidification Parameters and Chemical Composition of Nickel Superalloy IN-713C

100%

Szymszal J. , Gradoń P. , Binczyk F. , Cwajna J.

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6

Influence of Modification and Casting Technology on Structure of IN-713C Superalloy Castings

100%

Binczyk F. , Cwajna J. , Gradoń P. , Mańka M.

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tom Vol. 16, iss. 3

11--14

EN

The paper presents the results concerning impact of modification (volume and surface techniques), pouring temperature and mould temperature on stereological parameters of macrostructure in IN713C castings made using post-production scrap. The ability to adjust the grain size is one of the main issues in the manufacturing of different nickel superalloy castings used in aircraft engines. By increasing the grain size one can increase the mechanical properties, like diffusion creep resistance, in higher temperatures. The fine grained castings. on the other hand, have higher mechanical properties in lower temperatures and higher resistance to thermal fatigue. The test moulds used in this study, supplied by Pratt and Whitney Rzeszow, are ordinarily used to cast the samples for tensile stress testing. Volume modification was carried out using the patented filter containing cobalt aluminate. The macrostructure was described using the number of grains per mm2, mean grain surface area and shape index. Obtained results show strong relationship between the modification technique, pouring temperature and grain size. There was no significant impact of mould temperature on macrostructure.

7

Impact of a Structure on Durability of Modified Nickel-Base Superalloys in Creep Conditions/ Wpływ Struktury Na Trwałość W Warunkach Pełzania Modyfikowanych Nadstopów Na Bazie Niklu

100%

Cieśla M. , Mańka M. , Gradoń P. , Binczyk F.

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nr 4

8

The Effect of Temperature on the Result of Complex Modification of IN-713C Superalloy Castings

100%

Findziński R. , Gradoń P. , Binczyk F. , Mańka M.

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nr 4

9

Surface Modification of Cored, Thin Walled Castings of Nickel Superalloy IN-713C

88%

Binczyk F. , Cwajna J. , Gradoń P. , Mańka M. , Findziński R.

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tom Vol. 15, iss. 3

17--20

EN

In current casting technology of cored, thin walled castings, the modifying coating is applied on the surface of wax pattern and, after the removal of the wax, is transferred to inner mould surface. This way the modification leading to grain refinement occur on the surface of the casting. In thin walled castings the modification effect can also be seen on the other (external) side of the casting. Proper reproduction of details in thin walled castings require high pouring temperature which intensify the chemical reactions on the mould – molten metal interface. This may lead to degradation of the surface of the castings. The core modification process is thought to circumvent this problem. The modifying coating is applied to the surface of the core. The degradation of internal surface of the casting is less relevant. The most important factor in this technology is “trough” modification – obtaining fine grained structure on the surface opposite to the surface reproduced by the core.

10

Durability of MAR-247 and IN-713C Nickel Superalloys under Cyclic Creep Conditions

88%

Cieśla M. , Binczyk F. , Junak G. , Mańka M. , Gradoń P.

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tom Vol. 15, iss. 4

17--20

EN

Paper presents the assessment of impact of heat treatment on durability in low-cycle fatigue conditions (under constant load) in castings made using post-production scrap of MAR-247 and IN-713C superalloys. Castings were obtained using modification and filtration methods. Additionally, casting made of MAR-247 were subjected to heat treatment consisting of solution treatment and subsequent aging. During low-cycle fatigue test the cyclic creep process were observed. It was demonstrated that the fine-grained samples have significantly higher durability in test conditions and , at the same time, lower values of plastic deformation to rupture Δ□pl. It has been also proven that durability of fine-grained MAR-247 samples can be further raised by about 60% using aforementioned heat treatment.

11

Interactions at the mould - modifying coating - molten nickel alloy interface

88%

Binczyk F. , Śleziona J. , Gradoń P. , Michalska J. , Bąk S.

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2011

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tom Vol. 11, iss. 3

5-10

EN

The study describes thermal-chemical interactions that take place in the molten nickel alloy-ceramic mould system, where the mould is either coated with a modifying coating ('blue' mould) or is not ('white' mould). The ceramic mould based on zirconium silicate was made by investment process at the WSK Rzeszów Foundry. The main component of the modifying coating was cobalt aluminate CoAl2O4 added in an amount of 10%. Thermodynamic calculations indicated the possibility of chemical reactions taking place between the chemically active nickel alloy constituents (Al, Ti, Hf, Ta and Nb) and the components of a ceramic mould and modifying coating. The result of such interactions is the risk of the formation of cracks on the surface of mould and molten metal penetration into these cracks, combined with the formation of casting defects, like burns-on, pitting, etc., as proved by extensive X-ray microanalysis. Changes of chemical composition in the surface layer of castings were also reported.

12

Evaluation of Heat Capacity and Resistance to Cyclic Oxidation of Nickel Superalloys

88%

Przeliorz R. , Góral M. , Gradoń P. , Binczyk F. , Mikuszewski T.

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13

Durability of MAR-247 and IN-713C Nickel Superalloys under Cyclic Creep Conditions

88%

Cieśla M. , Junak G. , Gradoń P. , Binczyk F. , Mańka M.

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nr 4

14