42 research outputs found
Differential expression of Snail1 transcription factor and Snail1-related genes in alveolar and embryonal rhabdomyosarcoma subtypes.
Density as a factor limiting the workability of P/M materials
In this study a general scheme expressing the factors which affect a workability of powder materials is presented. It was found from laboratory experiments that workability of powder metal materials is limited by their density. Aluminium based materials with additions of Cu, Ni and Sn were used in the experiments. Workability determined in compression tests depends strongly on a sintered density, independently of the chemical composition of material. A linear dependence between workability and sintered density was found. The results are related to relatively high density values, taken from the range of 0.85-0. 96 of theoretical density
Study of the deformability of 5xxx series aluminum alloys with high Mg content in a semi-industrial extrusion process
W pracy przedstawiono wyniki bada艅 procesu wyciskania na gor膮co stop贸w AlMg o wysokich zawarto艣ciach Mg; analiz臋 odkszta艂calno艣ci materia艂u i badania w艂asno艣ci wytrzyma艂o艣ciowych wyrobu. Pr贸by wyciskania kszta艂townik贸w ze stop贸w aluminium w gatunkach PN-EN 5083 i PN-EN 5019 wykonano na p贸艂przemys艂owej prasie hydraulicznej poziomej o nacisku 5 MN, z wykorzystaniem matryc p艂askich 2-otworowych. Analizowano parametry procesu wyciskania oraz w艂asno艣ci mechaniczne kszta艂townik贸w wyciskanych ze stop贸w o ro偶nej zawarto艣ci Mg. Okre艣lono maksymaln膮, dopuszczaln膮 pr臋dko艣膰 wyp艂ywu metalu z otworu matrycy i graniczne temperatury solidus i likwidus ww. stop贸w w zale偶no艣ci od zawarto艣ci Mg w stopie.This paper presents the results of studies of the hot extrusion process of AlMg aluminum alloys with high Mg content; analysis of material deformability, and tests of product strength properties. Trial extrusions of sections made of aluminum alloy grades PN-EN 5083 and PN-EN 5019 were conducted on a semi-industrial horizontal hydraulic press with a pressing force of 5 MN using 2-hole flat dies. Extrusion process parameters and mechanical properties of sections extruded from alloys of varying Mg content were analyzed. The maximum acceptable rate of metal extrusion from the die hole and limit solidus and liquidus temperatures of the aforementioned alloys were determined depending on the Mg content in the alloy
Influence of Mg Content on Deformability of AlMg Alloys during Extrusion
In this study the research on deformability of AlMg alloys with high Mg contents in extrusion was carried out. The different shapes from AlMg alloys containing 3.5%, 4.5% and 5.5% of Mg were extruded on 500 T semi-industrial press by using one-hole and multi-hole flat dies. The extrudates surface quality was under investigations in relation with the temperature-speed parameters of the extrusion process. The metal exit speed was estimated depending on the extrudates shape, wall thickness and Mg content. The alloy鈥檚 border solidus and liquidus temperatures were also determined
Influence of Mg Content on Deformability of AlMg Alloys during Extrusion
In this study the research on deformability of AlMg alloys with high Mg contents in extrusion was carried out. The different shapes from AlMg alloys containing 3.5%, 4.5% and 5.5% of Mg were extruded on 500 T semi-industrial press by using one-hole and multi-hole flat dies. The extrudates surface quality was under investigations in relation with the temperature-speed parameters of the extrusion process. The metal exit speed was estimated depending on the extrudates shape, wall thickness and Mg content. The alloy鈥檚 border solidus and liquidus temperatures were also determined
Analysis of mechanical properties and dimensional accuracy of hollow thin-walled shapes extruded from AW6082 alloy
W pracy przedstawiono wyniki bada艅 w艂a艣ciwo艣ci wyciskanych cienko艣ciennych
(grubo艣膰 艣cianki ok. 1,2 mm) kszta艂townik贸w zamkni臋tych ze stopu AW6082 w stanie
T5. Kszta艂towniki wyciskano metod膮 wyciskania zgrzewaj膮cego, za pomoc膮 6-otworowych
matryc mostkowo-komorowych. Optymalizowano parametry wyciskania zmieniaj膮c
pr臋dko艣膰 wyciskania oraz szybko艣膰 ch艂odzenia. Wyznaczono w艂a艣ciwo艣ci mechaniczne,
twardo艣膰, grubo艣膰 艣cianek oraz chropowato艣膰 powierzchni kszta艂townik贸w
poddanych wyciskaniu z r贸偶n膮 pr臋dko艣ci膮 (9, 10 i 12 m/min), ch艂odzonych na
wybiegu prasy z r贸偶n膮 szybko艣ci膮 ch艂odzenia (natryskiwanie wodne-spray, fala wodna)
oraz starzonych sztucznie w temperaturze 180oC w czasie 2 godzin. Na podstawie
bada艅 stwierdzono, 偶e przy najwy偶szej zastosowanej pr臋dko艣ci wyciskania 12 mm/min
uda艂o si臋 osi膮gn膮膰 wysokie w艂a艣ciwo艣ci mechaniczne oraz drobnoziarnist膮 r贸wnomiern膮
struktur臋. Na podstawie bada艅 grubo艣ci profili stwierdzono, 偶e pomimo
otrzymania wyrobu o zadowalaj膮cej tolerancji grubo艣ci istnieje konieczno艣膰 korekty
matrycy, aby uzyska膰 bardziej r贸wnomierny rozk艂ad. Zmiana grubo艣ci 艣cianki owalnego
profilu wynika nie tylko ze szczeliny wyp艂ywu ale r贸wnie偶 z trudnego do przewidzenia
na etapie projektowania ugi臋cia matrycy podczas wyciskania. Pr臋dko艣膰 wyciskania
wp艂ywa r贸wnie偶 na jako艣膰 powierzchni profilu, kt贸ra wyra偶ona poprzez parametr
chropowato艣ci Ra jest najgorsza przy wyciskaniu z pr臋dko艣ci膮 9m/min. W wyniku
wzrostu pr臋dko艣ci wyciskania do 10 lub 12 mm/min chropowato艣膰 obni偶a si臋, co
poprawia jako艣膰 powierzchni. Zmiana szybko艣ci ch艂odzenia z ch艂odzenia powietrzem
na natryskiwanie wodne lub za pomoc膮 tzw. fali wodnej spowodowa艂a wzrost wytrzyma艂o艣ci
do zak艂adanej i po偶膮danej przez odbiorc臋 ko艅cowego tj. Rm, > 310 MPa, ale
jednocze艣nie nie wp艂yn臋艂o to na znaczny spadek wyd艂u偶enia wzgl臋dnego A.This paper presents the results of tests of the properties of hollow thin-walled (wall thickness
approx. 1.2 mm) shapes made of AW6082 alloy in T5 state. Shapes were extruded using the
bonding extrusion method, by means of 6-hole porthole dies. Extrusion parameters were
optimized by changing the rate of extrusion and cooling. Mechanical properties, hardness,
wall thickness and surface coarseness of shapes subjected to extrusion at various rates (9, 10
and 12 m/min), cooled on the press coasting at different cooling rates (water spray, water
wave), and artificially aged at a temperature of 180
oC over 2 hours, were determined.
Based on the tests, it was found that high mechanical properties and a uniform, finegrained
structure were successfully achieved at the highest applied extrusion rate of 12
mm/min. Based on the shape thickness measurements, it was determined that, despite
achievement of a product of satisfactory thickness tolerance, it is necessary to correct the die
to obtain more uniform distribution. The change of the wall thickness of the oval shape
results from the complexity of the die orifice and also from the die deflection during
extrusion, which is difficult to predict at the designing stage. Extrusion rate also has an
impact on the surface quality of the shape, which is expressed by the parameter of
coarseness Ra, and this quality was lowest for extrusion at a rate of 9 m/min. As a result of
an increase in extrusion rate from 10 to 12 mm/min, coarseness is reduced, improving
surface quality. The change in cooling rate from air cooling to water spraying or by means
of a so-called water wave caused an increase of strength to the level assumed and desired by
the end recipient, i.e. Rm, > 310 MPa, but at the same time, did not have an impact on the
significant reduction of relative elongation A