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Experimental Verification of the Cast Iron Solidification Model

Mendakiewicz Jerzy

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 3

91--94

EN

The article concerns the experimental verification of the numerical model simulating the solidification and cooling processes proceeding in the domain of cast iron casting. The approximate course of the function describing the evolution of latent heat and the value of substitute specific heat resulting from its course were obtained using the thermal and derivative analysis (TDA) method The TDA was also used to measure the cooling curves at the distinguished points of the casting. The results obtained in this way were compared with the calculated cooling curves at the same points. At the stage of numerical computations, the explicit scheme of the finite difference method was applied. The agreement between the measured and calculated cooling curves is fully satisfactory.

2

Decomposition study of in vivo phytoplankton absorption spectra aimed at identifying the pigments and the phytoplankton group in complex case 2 coastal waters of the Arabian Sea

Shaju S. S., Minu P., Srikanth A. S., Ashraf P. M., Vijayan A. K., Meenakumari B.

Oceanological and Hydrobiological Studies

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2015

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Vol. 44, No. 3

282--293

EN

Phytoplankton modify the optical properties of the seawater by altering the subsurface light field. Information on the accessory pigments present in the phytoplankton helps to differentiate major phytoplankton classes or taxonomic groups. The variability in the absorption spectra of phytoplankton and particulate matter of case 2 coastal waters of the Southeastern Arabian Sea were studied from June 2010 to November 2011. The phytoplankton specific absorption coefficient, at 440 nm and 675 nm, a*ph (440) and a*ph (675) varied from 0.018 to 0.32 m2 mg-1 and from 0.0005 to 0.16 m2 mg-1, respectively. The 4th derivative spectra computed for each in vivo absorption spectrum showed that the amplitude of maxima obtained is proportional to the concentration of the chromoprotein which absorbed that wavelength. Regression of pigment concentration against the 4th derivative spectral coefficient showed that the measurements of particulate absorption could provide quantitative information on chlorophyll a and other accessory pigment concentrations. Fucoxanthin and diadinoxanthin, the carotenoid pigments found in the diatoms were identified from the derivatives peaks. The study demonstrates the utility of using the 4th derivative analysis as a tool to identify the dominating phytoplankton group and its pigment composition.

3

Effect of accessory pigment composition on the absorption characteristics of a dinoflagellate bloom in a coastal embayment

Vijayan A. K., Somayajula S. A.

Oceanologia

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2014

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No. 56 (1)

107--124

EN

The light absorption properties of a dinoflagellate (Noctiluca scintillans Macartney) bloom in Manila Bay were analysed during the onset of a whole-bay-scale bloom in March 2004. The chlorophyll a concentrations varied over a very wide range from 1.4 µg l-1 to extremely high values of 521 µg l-1. The chlorophyll specific absorption coefficients of phytoplankton (a*ph(λ)) varied significantly in shape and magnitude. The spectrally averaged values of a*ph(λ) varied by two orders of magnitude within and outside the bloom patch. The total suspended solid concentration was high in the middle of the bay (≥4 mg l-1). The non-photosynthetic pigment (NPP) index was ~0.6 at most of the stations, mainly due to the presence of photoprotective pigments like zeaxanthin, lutein and neoxanthin, which led to variations in the blue absorption maxima of the chlorophyll-specific absorption coefficients. The absorption properties of the accessory pigments were masked owing to the presence of overlapping pigment absorption bands. The fourth derivative of the absorption spectra was able to resolve these overlapping features and enhance the absorption characteristics of prominent accessory pigments.

4

Model of Cu-Al-Fe-Ni bronze crystallization

Pisarek B. P.

Archives of Foundry Engineering

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2013

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Vol. 13, iss. 3

72--79

EN

According to the analysis of the current state of the knowledge shows that there is little information on the process of phase transformations that occur during the cooling Cu-Al-Fe-Ni hypo-eutectoid bronzes with additions of Cr, Mo and/or W, made additions individually or together, for the determination of: the type of crystallizing phases, crystallizing phases, order and place of their nucleation. On the basis of recorded using thermal and derivative analysis of thermal effects phases crystallization or their systems, analysis of the microstructure formed during crystallization - observed on the metallographic specimen casting ATD10-PŁ probe, analysis of the existing phase equilibrium diagrams forming elements tested Cu-Al-Fe-Ni bronze, with additions of Cr, Mo, W and/or Si developed an original model of crystallization and phase transformation in the solid state, the casting of high quality Cu-Al-Fe-Ni bronze comprising: crystallizing type phase, crystallizing phase sequence, place of nucleation.

5

Effect of the remelting on transformations in Co-Cr-Mo prosthetics alloy

Kacprzyk B., Szymczak T., Gumienny G., Klimek L.

Archives of Foundry Engineering

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2013

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Vol. 13, iss. 3

47--50

EN

In the article we were studing the impact of the remelting on transformations in Co-Cr-Mo prosthetics alloy. The TDA curves were analyzed, the microstructure was examined, the analysis of the chemical composition and hardness using the Brinell method was made. It was found that the obtained microstructure of the alloys that we studied do not differ significantly. In all four samples, microscopic images were similar to each other. The volume, size and distribution of the phases remain similar. Analysis of the chemical composition showed that all the samples fall within the compositions provided for the test alloy. Further to this the hardness of the samples, regardless of the number of remeltings did not show any significant fluctuations and remained within the error limit. After analyzing all the results, it can be concluded that the remeltings of the alloys should not have a significant impact on their properties. Secondarily melted alloys can be used for prosthetics works.

6

Selected problems of temperature measurement in welding processes

Słania J., Mikno Z., Wójcik M.

Advances in Manufacturing Science and Technology

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2007

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Vol. 31, nr 3

83-93

EN

The issues of temperature measurements directly from a weld pool and a weld are discussed. Problems occurring while measuring with thermocouples are shown. The issues of thermal and derivative analysis are discussed. Thermal and derivative analysis applications to research into welding technology are reviewed.

PL

W pracy poddano analizie zagadnienia związane z pomiarem temperatury bezpośrednio w jeziorku spawalniczym i spoinie. Przedstawiono problemy pomiarów prowadzonych z wykorzystaniem termopar. Omówiono zagadnienia związane z analizą termiczną i derywacyjną. Dokonano przeglądu zastosowania analizy termicznej i derywacyjnej w badaniach z zakresu spawalnictwa.

7

Monitorowanie produkcji i kontrola jakości stopów odlewniczych za pomocą programów komputerowych

Pietrowski S. K., Gumienny G., Pisarek B. P., Władysiak R.

Odlewnictwo - Nauka i Praktyka

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2005

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R. 7, nr 3

3-18

PL

Przedstawiono możliwości monitorowania produkcji i kontroli jakości stopów odlewniczych za pomocą autorskich programów komputerowych. Zostały one opracowane dla stopów żelaza, miedzi i aluminium. W systemie komputerowym wykorzystano metodą analizy termicznej i derywacyjnej (ATD). Przedstawiono reprezentatywne krzywe ATD i mikrostrukturę różnych gatunków staliwa, żeliwa, brązu aluminiowo-niklowo-żelazowego i siluminu wieloskładnikowego. Pomiędzy ich charakterystycznymi wielkościami a składem chemicznym i właściwościami mechanicznymi stopu występują określone zależności statystyczne. Przykładowo podano j e dla żeliwa sferoidalnego gatunku EN-GJS-400-15. Stanowią one podstawę budowy algorytmu autorskich programów komputerowych monitorowania i kontroli jakości stopów. Zaprezentowano schemat procesu kontroli stopów oraz przykładowe ekrany programu komputerowego kontroli żeliwa sferoidalnego. Programy komputerowe wdrożono w odlewniach staliwa, żeliwa i siłuminów w ramach realizacji projektów celowych.

EN

In this paper fhe possibility of production monitoring and quality control of casting alloys with self-written computer programmes have been presented. They have been elaborated for ferrous, copper and aluminum alloys. In the computer system thermal derivative analysis (TDA) method have been used. In this paper representative TDA curves and microstructure of: cast steel, cast iron, aluminum-nickel-iron bronze and mulficomponent silumin have been shown. Among their characteristic volumes, chemical composition and mechanical properties of alloy there are statistic relationships. Exemplary relationships for EN-GJS-400-15 ductile cast iron have been given in this work. They are the basis of computer programmes algorithm of monitoring and quality control of alloys. In this paper the scheme of alloys control process and exemplary screen displays of computer programme of ductile cast iron control have been presented. Computer programmes have been implemented in cast iron, cast steel and silumin foundries during the realization of grants.