Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 16

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

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
EN
The paper presents the effect of manganese on the crystallization process, microstructure and selected properties: cast iron hardness as well as ferrite and pearlite microhardness. The compacted graphite was obtained by Inmold technology. The lack of significant effect on the temperature of the eutectic transformation was demonstrated. On the other hand, a significant reduction in the eutectoid transformation temperature with increasing manganese concentration has been shown. The effect of manganese on microstructure of cast iron with compacted graphite considering casting wall thickness was investigated and described. The nomograms describing the microstructure of compacted graphite iron versus manganese concentration were developed. The effect of manganese on the hardness of cast iron and microhardness of ferrite and pearlite were given.
2
Content available Copper in Ausferritic Compacted Graphite Iron
EN
This paper shows how it is possible to obtain an ausferrite in compacted graphite iron (CGI) without heat treatment of castings. Vermicular graphite in cast iron was obtained using Inmold technology. Molybdenum was used as alloying additive at a concentration from 1.6 to 1.7% and copper at a concentration from 1 to 3%. It was shown that ausferrite could be obtained in CGI through the addition of molybdenum and copper in castings with a wall thickness of 3, 6, 12 and 24 mm. Thereby the expensive heat treatment of castings was eliminated. The investigation focuses on the influence of copper on the crystallization temperature of the graphite eutectic mixture in cast iron with the compacted graphite. It has been shown that copper increases the eutectic crystallization temperature in CGI. It presents how this element influences ausferrite microhardness as well as the hardness of the tested iron alloy. It has been shown that above-mentioned properties increases with increasing the copper concentration.
3
Content available Nickel in Compacted Graphite Iron
EN
The paper presents results of the research work concerning effects of nickel concentration on the crystallization process, microstructure and selected properties of the compacted graphite iron. Compacted graphite in the cast iron was obtained with use of the Inmold process. The study has comprised the cast iron containing nickel up to concentration providing obtainment of austenitic microstructure of the matrix. The effect of the nickel on temperature of the eutectic crystallization was specified. It has been presented composition of the cast iron matrix in function of nickel concentration in a casting with wall thickness of 3 mm and 24 mm. Moreover, it has been presented conditions defining the possibility of obtaining an austenitic and martensitic compacted graphite iron. Effect of the nickel on hardness of the cast iron was described.
EN
Structural modification of hypoeutectic Al-Si alloy EN-AC 46000 alloy influences its microstructure and mechanical properties. In a series of examinations the EN-AC 46000 alloy has been doped with Cr, W and Mo. The study involved the differential thermal analysis (DTA) and the light microscopy structural analysis of the samples cut from pressure die castings and from samples cast into the DTA cup. The DTA and microstructure analyses revealed new phases in the alloy doped with mentioned additives. The strength properties measurements of the alloys doped with Cr, W and Mo showed significant improvement in tensile strength and elongation, while preserving good hardness.
EN
This paper presents the results of hypoeutectic 226 grade alloy as well as prepared on its basis Al-Si alloy containing Cr, V and Mo. The additives tested were added as AlCr15, AlV10 and AlMo8 master alloys. Alloys tested were poured into DTA sampler as well as using pressure die casting. An amount of Cr, V and Mo additives in alloy poured into DTA sampler comprised within the range approximately 0.05-0.35%. Alloys to pressure die casting contained 0.05-0.20% Cr, V and Mo. The crystallization process was examined using the derivative thermal analysis (DTA). The microstructure of castings made in the DTA sampler as well as castings made with use of pressure die casting were examined. The basic mechanical properties of castings made using pressure die casting were defined too. It has been shown in the DTA curves of Al-Si alloy containing approximately 0.30 and 0.35% Cr, Mo, and V there is an additional thermal effect probably caused by a peritectic crystallization of intermetallic phases containing the aforementioned additives. These phases have a morphology similar to the walled and a relatively large size. The analogous phases also occur in pressure die casting alloys containing 0.10% or more additions of Cr, V and Mo. The appearance of these phases in pressure die casting Al-Si alloys coincides with a decrease in the value of the tensile strength Rm and the elongation A. It has been shown die castings made of Al-Si alloys containing the aforementioned additives have a higher Rm and A than 226 alloy.
EN
The paper presents the results of the research on the effect of copper on the crystallization process, microstructure and selected properties of the compacted graphite iron. Compacted graphite in cast iron was obtained using Inmold process. The study involved the cast iron containing copper at a concentration up to approximately 4%. The effect of copper on the temperature of the eutectic crystallization as well as the temperature of start and finish of the austenite transformation was given. It has been shown that copper increases the maximum temperature of the eutectic transformation approximately by 5 oC per 1% Cu, and the temperature of the this transformation finish approximately by 8 o C per 1% Cu. This element decreases the temperature of the austenite transformation start approximately by 5 oC per 1% Cu, and the finish of this transformation approximately by 6oC per 1% Cu. It was found that in the microstructure of the compacted graphite iron containing about 3.8% Cu, there are still ferrite precipitations near the compacted graphite. The effect of copper on the hardness of cast iron and the pearlite microhardness was given. This stems from the high propensity to direct ferritization of this type of cast iron. It has been shown copper increases the hardness of compacted graphite iron both due to its pearlite forming action as well as because of the increase in the pearlite microhardness (up to approx. 3% Cu). The conducted studies have shown copper increases the hardness of the compacted graphite iron approximately by 35 HB per 1% Cu.
EN
The basic aim of this study is to investigate the effect of vanadium and tungsten on the crystallization process, microstructure and mechanical properties of silumin grade EN-AC 46000. The research involved a derivative thermal analysis DTA of the crystallization process, the metallographic analysis as well as the mechanical properties. The metallographic analysis was carried out on pressure die castings and made in the DTA probe. Vanadium and tungsten were added simultaneously to silumin in amount of approximately 0.1; 0.2; 0.3 and 0.4%. The DTA studies have shown the similar shape of all crystallization curves. It has been shown the additives of vanadium and tungsten in pressure die cast silumin can significantly increase its tensile strength as an well as elongation.
EN
This article presents the results of studies in the hypoeutectic silumin destined for pressure die casting with the simultaneous addition of chromium and tungsten. The study involved the derivative and thermal analysis of the crystallization process, metallographic analysis and mechanical properties testing. Silumin 226 grade was destined for studies. It is a typical silumin to pressure die casting. AlCr15 and AlW8 preliminary alloys were added to silumin. Its quantity allowed to obtain 0.1, 0.2, 0.3 and 0.4% of Cr and W in the tested alloy. Studies of the crystallization process as well as the microstructure of the silumin poured into DTA sampler allowed to state the presence of additional phase containing 0.2% or more Cr and W. It has not occurred in silumin without the addition of above mentioned elements. It is probably the intermetallic phase containing Cr and W. DTA studies have shown this phase crystallizes at a higher temperature range than α (Al) solid solution. In the microstructure of each pressure die casting containing Cr and W the new phases formed. Mechanical properties tests have shown Cr and W additives in silumin in an appropriate amount may increase its tensile strength Rm (about 11%), the yield strength Rp0.2 (about 21%) and to a small extent elongation A.
EN
The analysis of the primary crystallization of wear corrosive-erosive high chromium cast steel was introduced in the article on the basis of investigations the widened method of the differential thermal analysis with testers DTA-C and DTA-Is. The use of these testers enabled the analysis of crystallization for the various rates of cooling.
10
Content available remote The estimation of quality refining covers
EN
This article contains information concerning of the analysis the possibility of defining refinery qualities of the slag based thermophysical and thermodynamical data. The paper presents a model of slag refining processes and a method of determining the reduction capability of slag solutions. Slag was analysed with the use of the DTA methods. The study of computer programme including the satisfactory number of data, both thermodynamical how and experimental - gathered with literature and own investiganion, the simpler qualification of optimum proprieties of slags would make possible. Settled by programme of areas the verification it is possible to the end to conduct in the support about proposed by A. W. Bydałek method of the modelling processes of refinement from it utilization the derivatograph or directly in conditions industrial. The isues presented deals not only with refining copper and melting stages, but also of the idea building an optimization program. In its assumption the program is supposed to check and search specific data very quickly on the particular types of slag..User starting programme should have the possibility of choice kind of the information.
11
Content available remote Primary and secondary crystallization of modified hypoeutectic chromium cast iron
EN
The paper presents investigations of crystallization of modified hypoeutectic wear resistant chromium cast iron which contains carbon about 2% and chromium on three levels (12%, 18% and 25%). Three substances were applied to the modification (boron carbide (B4C), ferroniobium (FeNb) and mixture of ferroniobium and mischmetal (RE)). The investigations of crystallization were conducted the DTA method in DTA-C and DTA-Is testers. The influence on the course of the process of primary and secondary crystallization was observed.
EN
Thermo-physical properties are the critical input parameters in computational models of solidification and casting simulations. In thermodynamics, the enthalpy is quotient of thermodynamic potential of a system, which can be used to calculate the useful work obtainable from a closed thermodynamic system under constant pressure. Differential thermal analysis has been used to study melting and solidification paths in the cobalt based superalloy FSX-414. The temperature enthalpy curve was determined from differential thermal analysis curves obtained from solidification curves. A solidification simulation of a cobalt base multi-component alloy casting was carried out to predict cooling and shrinkage porosity in the casting of a turbine engine vane segment. The effect of latent heat on the heat transfer calculation was considered by enthalpy method.
13
Content available remote Influence of selected modifiers on crystallization curve of chromium cast iron
EN
In article was introduced the results of investigations of modified chromium cast iron crystallization process. It the cast iron about composition of basic elements C = 2,8 % and Cr = 18% was modified with five substances (boron carbide, ferrosilicon, ferrocalciumsilicon, ferroniobium and ferroniobium with ferrovanadium). Influence on course of primary and secondary crystallization process was observed. The investigations of crystallization was conducted DTA method in tester DTA - C.
14
Content available remote The estimation slag refining features for the Cu-Si alloys melting process
EN
In the paper a method of determining the reduction capability of slag solutions was used. The extraction of metallurgical slag during the process of melting of copper alloys can be intensified by addition of carbides. To analyse the process author has made an effort to estimate refining efficiency of complicated sets of reagents in real industrial systems. The paper presents the analysis of the State of art in the field of metallurgy of silicium bronze.
PL
Brązy krzemowe odznaczając się obecnością składników węglikotwórczych (min.: krzem, żelazo, mangan), w celu zapewnienia wysokiej jakości powierzchni oraz odpowiednich właściwości wytrzymałościowych, wymagają precyzyjnej obróbki w stanie ciekłym. Głównym zabiegiem technologicznym wpływającym na jakość końcową odlewów jest rafinacja dla której istotną cechą jest zdolność rafinacyjna stosowanych środków rafinacyjnych. Pokazany zostanie sposób oceny zdolności rafinacyjnej żużli dostosowanych do warunków topienia brązów krzemowych, oraz weryfikacja uzyskanych wskazań w warunkach przemysłowych.
15
EN
The thermal analysis is very effective tool in the study of thermophysical and thermodynamical properties (e.g. temperatures of phase transformations, latent heats -enthalpies of phase transformations,...) among others, metallic systems. One of the most widespread methods of thermal analysis used for the description of metallic systems behaviour is the Differential Thermal Analysis - DTA. The aim of our work was study of characteristic phase transformation temperatures (temperatures of solidus - T$ and liquidus - TL) of lead-free solders on the base of tin. In total 22 alloys with different ratios of individual elements Ag, Cu, In, Sb, Bi, Zn and Sn were prepared experimentally. In addition, six alloys of lead-free solders produced commercially (Kovohute Pf ibram) were used and the Pb-Sn solder served as a comparative alloy. The alloys were prepared by smelting of input metals in the graphite crucible followed by casting into graphite boat. Temperatures of solidus and liquidus were obtained with use of experimental laboratory system SET ARAM SETSYS 18TM TG/DTA/TMA. Samples of solders in the form of small disordered pieces (size up to approx. 3 mm and max. mass 0.2 g) were during measurement heated and cooled in a controlled manner at the rate of 4°C/min. The A12O3 crucibles were used for measurement. Argon (purity > 99.999999%) was used for washing of the inert space of oven before each analysis (flow time approx. 15 min), then evacuation followed and again filling up with argon. During analysis the constant dynamical atmosphere was kept in the oven space (flow rate of argon was 2 1/h). Differences between experimentally determined temperatures of Ts, TL acquired during controlled heating and cooling were observed. These differences could be influenced not only by undercooling, but also by dynamics of measuring process.
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.