Wyniki wyszukiwania - BazTech

1

Application of Natural and Artificial Ageing on Multiply Remelted AlSi9Cu3 Alloy

Matejka M., Bolibruchova D.

Archives of Foundry Engineering

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2019

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iss. 2

60--66

EN

This article focuses on the study of the influence of remelting and subsequent natural and artificial ageing on the structure of recycled AlSi9Cu3 alloy with increased iron content. The assessed changes in eutectic silicon and iron-based intermetallic phases were carried out using optical and scanning electron microscopy. The degradation of the eutectic silicon morphology due to remelting occurred only at the highest numbers of remelting. The effect of remelting the investigated alloy, which is accompanied by a gradual increase in wt. % Fe, began to manifest significantly through a change in the length of the ferric phases after the fourth remelting. As expected, the artificial ageing process has proven to be more effective than natural ageing. It has led to a change in the eutectic silicon morphology and has been beneficial in reducing the lengths of adverse ferric phases. The use of alloys with higher numbers of remelting, or with greater “contamination”, for the manufacture of shape-challenging castings is possible when using a suitable method of eliminating the negative factors of the remelting process. The results of our investigation show a suitable method of the above elimination the application of heat treatment T5 – via artificial ageing.

2

Odporność tynków polimerowych na wzrost glonów jako cecha ich trwałości

Wiejak A.

Materiały Budowlane

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2016

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nr 9

21--22

3

Thermal Conductivity Coefficient of PUR Insulation Material from Pre-Insulated Pipes After Real Operation in District Heating Networks and After Artificial Ageing Process in Heat Chamber

Kręcielewska E., Menard D.

Ciepłownictwo, Ogrzewnictwo, Wentylacja

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2015

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T. 46, nr 2

46--52

EN

Pre-insulated pipelines, because of foam polyurethane (PUR) lifetime, are designed for 30 years of operation. During operation insulation foam is subject to natural process of ageing, resulting in changing of its basic thermal and mechanical properties. As a result of ageing, an increase (worsening) of insulation thermal conductivity coefficient follows. The Research Laboratory in Heat-Tech Center (LB HTC) from Veolia Energy Warsaw has started a research project, which aim is to determine actual values of thermal conductivity coefficient of pipe insulations, changing over time, under real operating conditions of the district heating network. The Laboratory also performs in parallel studies on insulation of preinsulated pipes after artificial ageing process according to the norm EN 253. The publication presents the results of the tests of thermal conductivity of PUR foam insulation of the pre-insulated pipe ageing in natural and artificial environments.

PL

Ze względu na żywotność pianki PUR rurociągi preizolowane projektowane są na 30 lat eksploatacji. Podczas pracy izolacja ulega procesowi naturalnego starzenia, zmieniają się jej podstawowe właściwości termiczne i mechaniczne. W wyniku starzenia się izolacji następuje wzrost (pogorszenie) współczynnika przewodzenia ciepła. Laboratorium Badawcze Heat-Tech Center (LB HTC) Veolii Energia Warszawa rozpoczęło projekt badawczy, którego celem jest określenie zmian wartości współczynnika przewodzenia w czasie, w rzeczywistych warunkach pracy sieci ciepłowniczej. Równolegle Laboratorium prowadzi badania izolacji z rur preizolowanych po procesie przyspieszonego starzenia zgodnie z normą EN253. Przedstawiono wyniki badań współczynnika przewodzenia ciepła izolacji z pianki PUR z rur preizolowanych starzonych w środowisku naturalnym i sztucznym. Artykuł był przedstawiony na konferencji w Sztokholmie.

4

Influence of Natural Ageing on Impact Strength of the EN AC-AlSi9Cu3(Fe) Alloy

Pezda J., Jarco A.

Archives of Foundry Engineering

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2015

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Vol. 15, iss. 1 spec.

81--84

EN

Growing market demand, more and more efficient and cleaner vehicles create a challenge for automotive industry. Properties of aluminum, such as: high strength stiffness to weight ratio, high fluidity and castability, easy machinability and weldability and good corrosion resistance make them ideal candidate to replacement of a heavier materials used in vehicles, and the same, have direct effect on fuel consumption. Comparing to steel, titanium or carbon fibers, aluminum alloys are characterized by low impact strength, which can be improved by a heat treatment. In this study one investigated the effect of the heat treatment (natural ageing) on the EN AC-AlSi9Cu3(Fe) alloy modified with strontium. Solution heat treatment temperature’s ranges were selected on the base of heating (melting) curves recorded with use of the thermal derivative analysis (ATD) method. Temperatures of the solution heat treatment were 495°C, 510°C, and 525°C ± 5°C, while the solutioning time ranged from 15 to 105 minutes (15; 60 and 105 min.). Time of the ageing amounted to 1, 3 and 7 days. To determine impact strength of the alloy after performed heat treatment one implemented simplified Charpy test. Maximal values of the impact strength (9,6 J/cm2) were obtained for solutioning temperature 510°C and solutioning time 15 minutes, after seven days of ageing. Obtained results enabled determination of solutioning parameters, which allow obtainment of increased impact strength of the investigation alloy for the T4 heat treatment.

5

Badania wpływu starzenia naturalnego na wybrane właściwości wyrobów z polipropylenu z dodatkiem środka oksybiodegradacyjnego

Jachowicz T., Gajdoš I.

Przemysł Chemiczny

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2014

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T. 93, nr 11

1983-1985

PL

Przedstawiono wyniki badań doświadczalnych dotyczących zmian na skutek starzenia naturalnego wybranych właściwości mechanicznych wyprasek wtryskowych wykonanych z polipropylenu z dodatkiem związku oksybiodegradacyjnego d2w.

EN

A com. oxybiodegrading agent was added (up to 2% by mass) to polypropylene processed by injection moulding to small lids studied then for degradability by natural ageing for 2 years. A small decrease in tensile strength and elongation at yield as well as a small increase in elasticity and hardness were obsd. during the expts.

6

Heat treatment of AlZn10Si7MgCu alloy and its effect on change of mechanical properties

Pezda J.

Archives of Foundry Engineering

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2012

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Vol. 12, iss. 2

135-138

EN

The most important parameters which predetermine mechanical properties of a material in aspects of suitability for castings to machinery components are: tensile strength (Rm), elongation (A5, hardness (HB) and impact strength (KCV). Heat treatment of aluminum alloys is performed to increase mechanical properties of the alloys mainly. The paper comprises a testing work concerning effect of heat treatment process consisting of solution heat treatment and natural ageing on mechanical properties and structure of AlZn10Si7MgCu alloy moulded in metal moulds. Investigated alloy was melted in an electric resistance furnace. Run of crystallization was presented with use of thermal-derivative method (ATD). This method was also implemented to determination of heat treatment temperature ranges of the alloy. Performed investigations have enabled determination of heat treatment parameters' range, which conditions suitable mechanical properties of the investigated alloy. Further investigations will be connected with determination of optimal parameters of T6 heat treatment of the investigated alloy and their effect on change of structure and mechanical/technological properties of the investigated alloy.

7

DSC investigations of the surface layer of an aged polypropylene/wood composite

Wąsicki A., Kościuszko A.

Polimery

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2011

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T. 56, nr 5

401-404

EN

DSC investigations of composite material taken from the surface of the molded pieces formed with the injection molding method have been carried out in order to evaluate changes caused by ageing processes. Composites were prepared from polypropylene (PP) filled with wood flour in the amount of 50 wt. %. Moldings were aged for four years in atmospheric conditions or laboratory conditions under UV radiation for 100, 200 and 300 hours, respectively. Essential ageing changes have been noticed on the surface of the samples exposed to the atmospheric conditions on the basis of DSC curves recorded during the second heating. PP crystallites are much less organized and melt in temperature lower by over 25 °C than PP crystallites in the non-aged composite. On the other hand, the crystallites considerably different in terms of organization degree and melting temperature may occur side by side in composite aged with UV irradiation. There have been observed on the DSC endothermic curves of such samples even up to three melting areas of crystallites differing in macromolecules organization.

PL

W celu oceny zmian zachodzących na skutek procesów starzenia w polipropylenie (PP) napełnionym w 50 % mas. mączką drzewną przeprowadzono badania DSC materiału pobranego z powierzchni kształtek formowanych metodą wtrysku. Kształtki wykonane z kompozytu polipropylen/drewno starzono w warunkach naturalnych przez cztery lata lub w warunkach laboratoryjnych pod wpływem promieniowania UV odpowiednio przez 100, 200 i 300 h. Na podstawie przebiegu krzywych topnienia DSC zarejestrowanych podczas drugiego ogrzewania próbek zaobserwowano wyraźne zmiany starzeniowe, które zaszły na powierzchni kształtek wystawionych na działanie czynników atmosferycznych. Krystality polipropylenowe wykazywały znacznie mniejszy stopień uporządkowania i topiły się w temperaturze niższej o 25 °C niż krystality w osnowie kompozytu nie poddanego procesowi starzenia. Starzenie kompozytu w warunkach przyspieszonych tj. pod wpływem promieniowania UV powodowało utworzenie struktur krystalicznych w wyraźny sposób różniących się stopniem uporządkowania i temperaturą topnienia. Na krzywych DSC takich próbek można było zaobserwować nawet trzy obszary topnienia krystalitów różniących się uporządkowaniem makrocząsteczek.

8

An Application of Thin Layer Chromatography Combined with Optical Densitometry to Quantitative Analysis of Diphenylamine and Its Initial Daughter Reaction Products in Single-Base Propellants Aged under Natural Conditions

Miszczak M.

Central European Journal of Energetic Materials

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2011

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Vol. 8, nr 2

107-116

EN

Thin Layer Chromatography (TLC) was used for the quantitative measurement of the composition of stabilizers used to retard chemical decomposition of single-base (SB) propellants i.e. diphenylamine (DPA), and its initial reaction products due to natural ageing of these propellants under natural (ambient) conditions with test results and certain observations in this matter, are presented. The quantitative determination of DPA and its reaction products was possible by a combination of TLC with the densitometric spectrophotometry technique in the UV detection region. The crucial stage of TLC analytical quantitations was complete extraction of the substances to be analysed from SB propellants nitrocellulose (NC), which was done by rapid dissolution of the SB propellant samples followed by dilution of the solutions obtained to such degree as to make possible TLC separation of the substances to be analysed from the NC "matrix" in which they are "trapped" when the solution is too viscous. Initial chemical changes of DPA in SB propellants resulting in the appearance of DPA initial daughter reaction products such as N-nitroso-DPA, 2-nitro-DPA and 4-nitro-DPA, gave important information on the natural ageing of these homogeneous propellants starting from their very short storage period (some days, weeks or months just after their manufacture) up to long storage lasting even 50 years.

9

Skuteczność zabezpieczenia drewna przed działaniem grzybów powodujących siniznę wtórną - ocena metod starzeniowych

Abram A.

Prace Instytutu Techniki Budowlanej

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2010

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R. 39, nr 2

31-39

PL

Przedstawiono wyniki badań skuteczności zabezpieczenia drewna przed sinizną wtórną. Badano możliwość zastąpienia starzenia naturalnego przyspieszonym starzeniem laboratoryjnym. Badania prowadzono z wykorzystaniem czterech środków dekoracyjno-ochronnych dostępnych na rynku polskim.

EN

The tests results of wood preservation effectiveness against repeated blue stain are presented. The possibility of replacing the natural ageing by artificial accelerated ageing was tested. Four decorative and preservative agents (available on the Polish market) were used during the tests.

10

Study of Mechanical Properties of Naturally Aged Double Base Rocket Propellants

Sućeska M., Matečić Mušanić S., Fiamengo I., Bakija S., Bakić A., Kodvanj J.

Central European Journal of Energetic Materials

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2010

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Vol. 7, nr 1

47-60

EN

Various chemical reactions and physical processes (such as stabilizer consumption, migration and evaporation of nitroglycerine, decomposition of nitroglycerine and nitrocellulose, etc.) take place in double based rocket propellants grains over the time, even under ambient storage conditions. The overall effect of these reactions and processes are changes of physical, chemical, thermal, ballistic and mechanical properties of rocket propellants with storage time, i.e. the reduction of the propellants performances and safe service life. The aim of this work was to evaluate the mechanical changes of rocket propellants – sustainers, built in in-service antitank guided missiles systems, induced by natural ageing at ambient conditions during up to 35 years of storage. The mechanical and viscoelastic properties were tested using a dynamic mechanical analyser, an uniaxial tensile and compression tester, and a notch toughness tester. The results have shown that the changes of the studied mechanical and viscoelastic properties are evident, although the results of the tests are rather scattered (as a consequence of measuring uncertainty, different ageing histories of propellants, etc.) or changes of some properties are not too pronounced. For example, after 15 years of storage at ambient conditions the glass transition temperature increases for about 5 C, the tan δ in the glass transition region decreases for about 5%, the storage and loss modulus at 25 °C increase for about 15%, Young modulus at 23 C increases up to 30%, the notch toughness at -30 C decreases up to 15%, etc. Along with these tests, the stabilizer content determination and proving ground ballistic tests were also done.

11

Wpływ starzenia naturalnego na wybrane właściwości folii polimerowej

Jachowicz T., Sikora J. W.

Zeszyty Naukowe Politechniki Rzeszowskiej. Chemia

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2009

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z. 20 [263]

47-50

PL

W artykule przedstawiono podstawowe informacje o starzeniu tworzyw polimerowych. Scharakteryzowano rodzaje starzenia oraz omówiono zagadnienia związane z odpornością tworzyw na starzenie, zjawiskami zachodzącymi w polimerach na skutek tego procesu oraz wpływem czynników środowiskowych. Przedstawiono wpływ starzenia naturalnego na zmianę wybranych właściwości tworzyw polimerowych, na przykładzie recyrkulacyjnej folii polimerowej z polichlorku winylu.

12

Badania wpływu czasu starzenia naturalnego walcówki z przewodowego stopu AlMgSi (seria 6xxx) na własności reologiczne drutów po obróbce cieplno-mechanicznej

Knych T., Mamala A., Smyrak B., Tarasek A.

Rudy i Metale Nieżelazne

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2005

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R. 50, nr 2

82-86

PL

W artykule zaprezentowano wyniki badań charakterystyk pełzania drutów ze stopu w gat. 6201 przeznaczonych na napowietrzne przewody elektroenergetyczne. Materiałem wsadowym do procesu ciągnienia jest walcówka w stanie T4 uzyskiwana metodą ciągłego odlewania i walcowania (Continuus Properzi), która charakteryzuje się zróżnicowanym czasem leżakowania, podczas którego zachodzą przemiany strukturalne znamienne dla starzenia naturalnego materiału. Stwierdzono, że charakterystyki pełzania drutu są silną funkcją czasu leżakowania walcówki oraz parametrów obróbki cieplno-mechanicznej. Uzyskane wyniki pozwalają na wnioskowanie praktyczne zmierzające do optymalizacji technologii przetwarzania stopów AlMgSi w warunkach przemysłowych.

EN

The article presents the results of the examination of 6201 alloyed wires creep characteristics used for power overhead lines. A batch to a drawing process is a rod in state T4 obtained by continuous casting and rolling (Continuus Properzi) after various times, during which structural changes typical for material's natural aging process take place. It was observed that wire's creep characteristics is a strong function of duration of material's (rod's) expectation for a process and thermo-mechanic processing parameters. The results presented in the article are a part of a wider program of a research on the influence of rod's natural aging process on wires' utilizable properties. Selected parts of examinations are presented in 1 and 2, this article is a supplement of issued raised in 1 and 2. The results lead to practical conclusions tending towards optimalization of processing technology of AlMgSi alloys in industrial conditions. Very few positions concerning the possibility of shaping AlMgSi wires' rheological properties can we find in literature. Majority of publications is dedicated to the issue of steering material's rheological potential at the stage of exploiting a finished good (a wire hung in span). Articles published by western scientific centers occupied in designing overhead lines and exploiting wires are most frequent. Such articles focus mainly on familiarizing with wires' creep process characteristics, giving exploitation recommendations, creating norms and other restrictions which condition material's rheological potential on the value of 10-year creep deformation. J. R. Harvey and C. A. Roest's articles both present wide range of examinations on various wires' creep processes in various conditions of stress and temperature and show how changing stress during the process of creep may change its character. The most valuable and interesting seem to be examinations on creep processes in conditions of stress and temperature negative gradient which lead to a temporary pause of creep process, which is obviously beneficial if taking the exploitation of a hung wire into consideration. The authors of the articles focus on pure mechanic examinations (change of stress or temperature), aiming at limiting the unprofitable creep process of a finished good. Thus, what seems to be very interesting, presented in this article, is the steering of material 's rheological capability during the stage of shaping its primary properties which may occur by a proper choice of thermal dressing parameters and rod's natural aging process in particular. The work was done within the project "The influence of rod's natural aging on the capability of drawing and shaping properties of AlMgSi wires" sponsored by MNil.

13

Badania wpływu czasu starzenia naturalnego walcówki z przewodowego stopu AlMgSi (seria 6xxx) na elektryczno-mechaniczne własności drutu osiągane w procesie końcowej obróbki cieplnej

Knych T., Mamala A., Smyrak B., Tarasek A.

Rudy i Metale Nieżelazne

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2004

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R. 49, nr 9

456-461

PL

Przedstawiono zagadnienie wpływu czasu starzenia naturalnego walcówki z przewodowego stopu AlMgSi gat. 6201 (wg PN-EN 515 stan T4) na zmianę własności mechanicznych i elektrycznych drutów w procesie końcowej obróbki cieplnej. Program obejmuje czternaście akcji badawczych prowadzonych systematycznie po określonym interwale czasu starzenia naturalnego walcówki. Stwierdzono zmienność własności wytrzymałościowych drutów starzonych sztucznie w analogicznych warunkach, lecz wytworzonych z walcówki po różnym czasie starzenia naturalnego. Wpływ starzenia naturalnego walcówki ujawnia się najmocniej w okresie pierwszego miesiąca oczekiwania materiału na ciągnienie. Uzyskane wyniki posiadają duże walory poznawcze i praktyczne umożliwiające lepsze zrozumienie zachowania się stopu AlMgSi podczas procesu przetwarzania na drut po stabilizacji własności walcówki oraz stabilizacji własności elektrycznych drutów ciągnionych z walcówki po długim czasie starzenia.

EN

The paper presents correlation natural ageing of AlMgSi conductor alloy rod and properties of material during artificial ageing of final wire. Satisfactory natural rod ageing process is fundamental due to quality of final wire. The problem is very important because natural ageing of rod is long-time element of making wire technology. Material for testing was classic continuously cast and rolled 9.5 mm diameter rod. After rolling process the rod was homogenized, supersaturated and naturally aged during different period of time. Next the rod was drawn in laboratory condition up to 3 mm diameter wire (as a standard and occasionally different diameters of wires), which was artificial aged up to eight hours at temperature about 160 degrees centigrade. The article shows the results of investigations on the influence of rod's natural ageing process on behaviours of wire during artificial ageing. It states significant effect on mechanical properties of wires and less significant effect on electric properties of wires during ageing. Dispensable time for maximal growth of tensile strength of aged wire decreases with increase natural ageing time of rod before drawing. Electrical resistance of wire during artificial ageing decreases continuously during rise period of ageing time. Essential influence of natural ageing time of wire during first month of rod ageing time is shown. In conclusion it should be minimal ageing time of rod in factory conditions.