PL
 |
EN
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 7

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  porowatość gazowa
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
Content available Influence of Defects on Deformation Behavior of High-Pressure Die-Casting Magnesium Alloys
Braszczyńska-Malik Katarzyna
Archives of Foundry Engineering
|
2023
|
Vol. 23, iss. 2
10--14
EN
The results of investigations of defects in AME-series magnesium alloys produced by the high-pressure die-casting method are presented. The analyzed magnesium alloys contain about 5 wt% aluminum and 1-5 wt% rare earth elements introduced in the form of mischmetal. The casts were fabricated using a regular type cold-chamber high-pressure die-casting machine with a 3.2 MN locking force. The same surfaces of the casts were analyzed before and after the three-point bending test in order to determine the influence of the gas and shrinkage porosity on the deformation behavior of the alloys. The obtained results revealed that the most dangerous for the cast elements is the shrinkage porosity, especially stretched in the direction perpendicular to the that of the tensile stress action. Additionally, the influence (Mg) solid solution and its interaction on the cracking process was described [alpha]  of deformation twins arise in the dendrites of the primary.
2
Content available Contribution to the Assessment of the Data Acquisition Effectiveness in the Aspect of Gas Porosity Defects Prediction in Ductile Cast Iron Castings
Ignaszak Z., Sika R., Rogalewicz M.
Archives of Foundry Engineering
|
2018
|
Vol. 18, iss. 1
35--40
EN
The article presents an example of analysis of the influence of selected parameters deriving from data acquisition in foundries on the occurrence of Gas porosity defects (detected by Visual testing) in castings of ductile cast iron. The possibilities as well as related effectiveness of prediction of this kind of defects were assessed. The need to rationally limit the number of possible parameters affecting this kind of porosity was indicated. Authors also benefited from expert group's expertise in evaluating possible causes associated with the creation of the aforementioned defect. A ranking of these parameters was created and their impact on the occurrence of the defect was determined. The classic statistical tools were used. The possibility of unexpected links between parameters in case of uncritical use of these typical statistical tools was indicated. It was emphasized also that the acquisition realized in production conditions must be subject to a specific procedure ordering chronology and frequency of data measurements as well improving the casting quality control. Failure to meet these conditions will significantly affect the difficulties in implementing and correcting analysis results, from which INput/OUTput data is expected to be the basis for modelling for quality control.
3
Content available Controlled Precipitation Gaseous Cavities in Aluminium Castings
Roučka J., Hotař J.
Archives of Foundry Engineering
|
2015
|
Vol. 15, iss. 4
124--128
EN
At thermal junctions of aluminium alloy castings and at points where risering proves to be difficult there appear internal or external shrinkages, which are both functionally and aesthetically inadmissible. Applying the Probat Fluss Mikro 100 agent, which is based on nano-oxides of aluminium, results in the appearance of a large amount of fine microscopic pores, which compensate for the shrinking of metal. Experimental tests with gravity die casting of AlSi8Cu3 and AlSi10Mg alloys have confirmed that the effect of the agent can be of advantage in foundry practice, leading to the production of castings without local concentrations of defects and without the appearance of shrinkages and macroscopic gas pores. Also, beneficial effect on the mechanical properties of the metal has been observed.
4
Content available Contribution to the Identification of Porosity Type in AlSiCu High-Pressure-Die-Castings by Experimental and Virtual Way
Ignaszak Z., Hajkowski J.
Archives of Foundry Engineering
|
2015
|
Vol. 15, iss. 1
143--151
EN
The paper concerns the problem of discontinuity in high pressure die castings (HPDC). The compactness of their structure is not perfect, as it is sometimes believed. The discontinuities present in these castings are the porosity as follow: shrinkage and gas (hydrogen and gas-air occlusions) origin. The mixed gas and shrinkage nature of porosity makes it difficult to identify and indicate the dominant source. The selected parameters of metallurgical quality of AlSi9Cu3 alloy before and after refining and the gravity castings samples (as DI - density index method), were tested and evaluated. This alloy was served to cast the test casting by HPDC method. The penetrating testing (PT) and metallographic study of both kinds of castings were realized. The application of the NF&S simulation system allowed virtually to indicate the porosity zones at risk of a particular type in gravity and high-pressure-die-castings. The comparing of these results with the experiment allowed to conclude about NF&S models validation. The validity of hypotheses concerning the mechanisms of formation and development of porosity in HPDC casting were also analyzed.
5
Content available remote Analysis of the influence oxygen and hydrogen during melting aluminium and his alloys
Bydałek A. W., Bydałek A.
Archives of Foundry Engineering
|
2011
|
Vol. 11, iss. 3
69-72
EN
In the work was stated term the analysis of ion influences in melting codnuction of aluminium and his alloys. Influence from hydrogen and oxygen, hydrogen and oxygen and steam water together was distinguished. Where have worked out the scheme of influences leading to gas porosity of aluminium and his alloys. In analysis was referred to theory of double electric layer. It was conducted the analysis regularity of opinion influence oxygen and hydrogen in melt aluminium in support on Allena - Hewitta dependence.
6
Content available remote Identyfikacja porowatości w kompozytach typu stop Al-cząstki ceramiczne wytwarzanych metodą odlewania odśrodkowego
Dolata-Grosz A., Śleziona J.
Archiwum Technologii Maszyn i Automatyzacji
|
2004
|
Vol. 24, nr 1 sp
57-66
PL
Jedną z przyczyn porowatości występującej w kompozytach odlewanych jest zagazowanie su-spensji kompozytowej. Porowatość gazowa jest największą trudnością do przezwyciężenia w technologiach wytwarzania kompozytów z udziałem ciekłej osnowy, szczególnie w metodzie mechanicznego mieszania, w czasie którego do kąpieli mogą być wprowadzone pęcherze gazowe, Ich występowanie, obserwowane w catej objętości odlewu, wpływa niekorzystnie m.in. na właściwości mechaniczne, a także zmniejsza odporność korozyjną kompozytu. Ponadto, zagazowanie zawiesiny, powstałe wskutek mechanicznego mieszania, przyczynia się do powstawania klasterów i aglomeratów cząstek ceramicznych. Typowe struktury kompozytów po odlewaniu grawitacyjnym, z ujawnioną porowatością pokazano na rys. l. W artykule przedstawiono wyniki badań rozmieszczenia porowatości w odlewach kompozytowych wytwarzanych za pomocą odlewania odśrodkowego.
EN
One of the reasons porosity occurs in cast composites is suspension's gassing. Gas porosity is probably one of the biggest problems in composites production with the liquid metal matrix, especially in slurry casting method. During the course of mixing the gases cavity can be introduced into the melt. Its presence, among other things, can be detrimental to the mechanical properties and corrosion resistance of the composites casting. Moreover, gassing of the suspended matter, being an effect of mechanical mixing, causes the formation of particle-porosity clusters and ceramic particles agglomerates. Typical microstructures of the composites after gravitational casting, with porosity are shown in Fig. 1. In this work the results of research the porosity distribution in composites cast producing by the centrifugal casting method has been presented.
7
Diffusional evolution of the gas pores in hot pressed ceramics
Abyzov A.S., Panich A.E., Slezov V.V., Surowiak Z., Wodecka-Duś B.
Archiwum Nauki o Materiałach
|
2001
|
T. 22, nr 1
19-40
EN
The process of diffusional evolution (shrinkage or growth) of the gas pores in sintering of ceramics, stimulated by the diffusion of vacancies is considered. It is assumed that gas is partially or completely soluble in a matrix and the capacity of the system of vacancy sources and sinks is finite. The expression determining the porosity evolution at the final stage of the process is obtained.
PL
Rozpatrzono proces dyfuzyjny ewolucji (skurcz lub wzrost) porów gazowych podczas spiekania ceramiki, stymulowanej dyfuzją wakansów. Założono, iż gaz jest częściowo lub całkowicie rozpuszczalny w matrycy i że wydajność układu źródeł oraz studni wakansów jest skończona. Otrzymano równania określające rozwój porowatości w końcowym stadium procesu spiekania.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.