Wyniki wyszukiwania - Biblioteka Nauki

1

Badania stanu odkształcenia w wyrobach walcowanych klinami.

100%

Pater Z.

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1999

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tom R. 44, nr 11

595-598

PL

Przedstawiono rezultaty badań stanu odkształcenia w procesie walcowania poprzeczno-klinowego (WPK). W badaniach wykorzystano metodę pomiaru twardości. Określono wpływ podstawowych parametrów procesu, tj. kątów kształtującego alfa i rozwarcia klina beta oraz stopnia gniotu delta na wielkość odkształceń. Przedstawiono pomierzone doświadczalnie rozkłady odkształceń.

EN

The results of strain investigation in cross wedge rolling (CWR) process are presented in this paper. The method of hardness measurement is used in the experiments. The influence of basic CWR parameters (a forming angle alpha, a spreading angle beta, a relative reduction delta) on the strain state is examined. The strain fields obtained experimentally are presented, too.

2

Numerical analysis of splitting without waste based on cross-wedge rolling in double rolling mechanism

100%

Tofil A.

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tom Vol. 7, nr 17

73--76

EN

The article presents the results of numerical analysis of splitting without waste on the basis of cross wedge rolling in double rolling mechanism. The analysed process concerns rolling the charge of V-shaped groove, and rotary bending causing the split of the material. In the calculations a method of finite elements (FEM) was used. The obtained results allowed detailed analysis of the splitting process in terms of the level of deformation, strains, material breaking, flow kinematics and strength parameters.

3

Finished cross-wedge rolling of hollowed cutters

75%

Pater Z. , Bartnicki J.

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tom Vol. 51, iss. 2

205-211

EN

In this work, the results of the process analysis of rotary cutters manufacturing are presented. The possibility of manufacturing of a cutter with hollowed body, formed by means of the cross-wedge rolling method (CWR), was analyzed. In the research thermo-mechanical schema of FEM calculations was used, which was later verified in industrial tests. In this work the design of tools guaranteeing the rolling process, the distribution of wall thickness and distributions of strain in cutters body are presented. On the basis of calculations it was stated that it was possible to form hollowed cutters by means of cross-wedge rolling method. The conception of manufacturing of finished hollowed cutter is demonstrated. In this conception the process of burning on of cutting edge was replaced by its reducing in the body realized during rolling.

PL

W opracowaniu podano rezultaty analizy procesu wytwarzania noży obrotowych. Badano możliwość wytwarzania noża posiadającego korpus drążony, kształtowany metodą walcowania poprzeczno-klinowego (WPK). W badaniach zastosowano termomechaniczny schemat obliczeń MES, który zweryfikowano w próbach przemysłowych. W artykule przedstawiono konstrukcje narzędzi zabezpieczających proces walcowania, podano rozkłady grubości ścianek i rozkłady odkształceń w korpusach noży. Na podstawie obliczeń stwierdzono, że istnieje możliwość kształtowania noży drążonych metodą WPK. Przedstawiono również koncepcję wytwarzania noża na gotowo, w której proces wlutowywania ostrza zastapiono jego obciskaniem w korpusie realizowanym podczas walcowania.

4

Numerical Analysis of the Cross-Wedge of a Hollow Rail Axle

75%

Pater Z. , Lis K. , Walczuk-Gągała P.

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tom Vol. 14, no 1

145--153

EN

The article presents an innovative method of manufacturing hollow rail axles using three combined wedge rolls. The proposed solution was evaluated using numerical simulation. Two cases of forming, differing in the wall thickness of the billet, were analysed. The geometry of the formed axles, distributions of the effective strain, temperature and damage function were presented. Moreover, the changes to the forces and torques acting on each roll were presented.

5

Numerical and experimental research on cross wedge rolling hollow shafts with a variable inner diameter

63%

Shen J. , Wang B. , Zhou X. , Li J.

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tom Vol. 19, no. 4

1497--1510

EN

The precise forming of inner hole has been a major technical difficulty in the cross wedge rolling (CWR) of hollow shaft. This paper proposes a new process to form hollow shafts with variable inner diameters by using the CWR with mandrel control. The forming characteristics and dimension precision of this process are analyzed by combining finite element modelling (FEM) and forming trials. The hole step of hollow shaft with variable inner diameter is formed in a spiral pattern. The helixes result in many micro-steps in hole step when forming the right-angle inner step. The metal flow lines demonstrated that mandrel step hindered the axial metal flow of inner hole and the metals were accumulated in hole step. The rolling load increases in the process of forming hole step. The mandrel is subjected to axial load when hole contacts the mandrel step. The roundness can be improved by reducing the mandrel diameter in knifing position. The axial accuracy of inner diameter can be classed as three parts: hole expansion, stable rolling, hole shrinkage. The compensated mandrel was designed to improve axial precision of inner diameter. The results showed that the inner hole dimension can be effectively controlled.

6

Walcowanie poprzeczno-klinowe odkuwek z wsadu kształtowego

63%

Pater Z.

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tom Vol. 75, nr 10

604-611

PL

W artykule poddano analizie przypadki kształtowania metodą walcowania poprzeczno-klinowego (WPK) odkuwek z wsadu o przekroju poprzecznym różnym od kołowego (kwadratowym i sześciokątnym). W procesach kształtowania wykorzystywano narzędzia (kliny), o kształtach stosowanych podczas walcowania z typowych wsadów cylindrycznych. W ramach analizy teoretycznej, bazującej na metodzie elementów skończonych, zasymulowano szereg przypadków kształtowania przebiegających przy różnym gniocie. Niektóre z zasymulowanych numerycznie przypadków WPK z wsadu kształtowego zrealizowano również w warunkach laboratoryjnych Politechniki Lubelskiej. Na podstawie wykonanych prac badawczych w sposób jednoznaczny wykazano, że stosując metodę WPK można kształtować odkuwki z wsadu o przekroju poprzecznym różnym od kołowego.

EN

This paper presents the analysis of forming cases by means of cross wedge rolling (CWR) of forgings from billets with cross-section different from circular one (square and hexagonal). The tools of shapes applied during rolling from standard cylindrical billet were used in forming processes. Within the scope of theoretical analysis, basing on the finite element method, numerous cases of forming at different reduction ratio were simulated. Some of the numerically simulated CWR cases from profiled billets were also realized in laboratory conditions at Lublin University of Technology. On the basis ofresearch works it was stated that the application ofCWR method allows forming of forgings from billets with cross section different from circular one.

7

Microstructure and mechanical properties of TC4 titanium alloy hollow shaft formed by cross wedge rolling

63%

Feng P. , Yang C. , Wang B. , Li J. , Liu R.

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tom Vol. 21, no. 3

737--751

EN

Production of hollow shafts satisfying mechanical performance requirements can well meet the needs of lightweight. The purpose of this work is to investigate the effect of cross wedge rolling (CWR) process parameters on microstructure and mechanical properties of TC4 titanium alloy hollow shafts, so as to ensure the feasibility of forming TC4 titanium alloy hollow shaft by CWR. The results demonstrate that the initial deformation temperature, area reduction, wall thickness, and mandrel have significant effects on the volume fraction of primary alpha phase (fα_p), morphology of alpha phase and interface of alpha/beta phase. The decrease of the fα_p, the increase of fine secondary alpha phase content and the increase of the number of alpha/beta phase interfaces can increase the strength of TC4 alloy hollow shafts, but decrease the elongation. When the initial deformation temperature is 950 °C, the contribution of the thick secondary alpha phase is similar to that of the primary alpha phase, resulting in the decrease of strength. The strength is further improved owing to the grain refinement with the increase of area reduction to 60%. The strength decreases as the wall thickness increases owing to the non-uniform microstructure distribution, which can be improved by increasing the area reduction appropriately. The comprehensive mechanical properties of the workpiece rolled with a mandrel are evidently higher than that rolled without a mandrel. Under any forming condition in this work, every fracture surface is covered with abundant dimples and voids, showing good ductile fracture characteristics.

8

Numerical And Experimental Study On Producing Aluminum Alloy 6061 Shafts By Cross Wedge Rolling Using A Universal Rolling Mill

63%

Tofil A. , Tomczak J. , Bulzak T.

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2015

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tom Vol. 60, iss. 2A

801--807

EN

The paper presents a selection of numerical and theoretical results of the cross wedge rolling process for producing stepped shafts made of aluminum alloy 6061. The numerical modeling was performed using the FEM-based Simufact Forming simulation software. In the simulations, we examined the kinematics of metal flow and determined the distribution patterns of effective strains, temperatures, axial stresses and the Cockroft-Latham damage criterion. Variations in the rolling forces were determined, too. The numerical results were verified experimentally using a universal rolling mill designed and constructed by the present authors. This machine can be used to perform such processes as cross wedge rolling, longitudinal rolling and round bar cropping. During the experiments, we examined process stability and finished product geometry and recorded the torques. The experimental results confirm that axisymmetric aluminum alloy shafts can be produced by cross wedge rolling with two rolls. Last but not least, the experiments served to evaluate the technological potential of the rolling mill used.

PL

W pracy przedstawiono wybrane wyniki badań teoretyczno – doświadczalnych procesu walcowania poprzeczno – klinowego odkuwki wałka stopniowanego ze stopu aluminium w gatunku 6061. Analizę teoretyczną przeprowadzono w programie Simufact Forming, bazującym na metodzie elementów skończonych. W trakcie symulacji analizowano kinematykę płynięcia materiału, wyznaczono rozkłady intensywności odkształcenia, temperatury, naprężeń w kierunku osiowym oraz kryterium zniszczenia wg Cockrofta Lathama. Ponadto określono parametry siłowe podczas walcowania. Weryfikacji doświadczalnej wyników modelowania numerycznego procesu walcowania dokonano w uniwersalnej walcarce kuźniczej, która stanowi własna konstrukcję. Zastosowana walcarka umożliwia realizacje takich procesów jak: walcowanie poprzeczno-klinowe, walcowanie kuźnicze wzdłużne oraz dzielenie bezodpadowe. Podczas eksperymentu analizowano stabilność procesu, geometrie ukształtowanych odkuwek oraz rejestrowano wartość momentów obrotowych. Uzyskane wyniki prowadzonych badań potwierdziły możliwość kształtowania osiowosymetrycznych odkuwek ze stopów aluminium metodą WPK dwoma walcami. W trakcie eksperymentu określono również możliwości technologiczne walcarki.

9

Investigation of the microstructure evolution and mechanical properties of a TC6 alloy blade preform produced by cross wedge rolling

63%

Li J. , Wang B. , Fang S. , Chen P.

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2020

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tom Vol. 20, no. 3

91--101

EN

Cross wedge rolling (CWR) is one of the most effective plastic deformation methods utilized for the production of shaft parts or non-shaft preforms with refined grains and improved mechanical properties. The main goal of this work was to study the influence of CWR process parameters on the microstructure evolution and mechanical properties of a TC6 alloy and determine the suitable process parameters for a TC6 alloy blade preform fabricated with CWR. The results showed that the volume fraction of the equiaxed α phase (fα_e) decreased from ~ 0.38 to ~ 0.04 by increasing the initial deformation temperature, and the elongation (El) also decreased from ~ 19.6 to ~ 11.8% because dislocation slip first started in the equiaxed grains and then dispersed into the adjacent grains. Thus, additional equiaxed grains contributed to an increased plasticity. Moreover, with an increasing area reduction, the value of fα_e increased from ~ 0.14 to ~ 0.31, and the grain refinement and microstructure uniformity also increased. In addition, the El was significantly reduced by over 50%, but the ultimate tensile strength (UTS) and yield strength (YS) increased under WC (water cooling) conditions due to the precipitation of the acicular secondary α phase and pinning effect of the small equiaxed α phase. Based on the determined suitable parameters, the TC6 alloy blade preform was successfully manufactured by CWR, the microstructure was evenly distributed, and the UTS, YS and El were 1120.1 MPa, 1020.9 MPa and 15.2%, respectively, which meet the current technical requirements.