Forward extrusion through steadily rotating conical dies. Part I: experiments

Ma, Xiang; Barnett, Matthew; Kim, Y. H.

doi:10.1016/j.ijmecsci.2004.03.017

Cited by 51 publications

(16 citation statements)

References 7 publications

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“…However, at higher apparent shear rate (8.5 s À1 ) the extrusion forces decreased from 140 to 90 kgf (by $ 60% reduction) for 23 wt % wood content used, and the entrance pressure dropped from 10 Â 10 5 to 8 Â 10 5 Pa (by 20% reduction) for 23 wt % wood content used by increasing die rotating speed from 0 to 70 rpm. This behavior was similar to the work by Ma et al 15,16 who found the extrusion load reduction of pure lead by using rotating conical dies. The fluctuations in the entrance pressure drop during the measurements were probably caused by the flow of the composite melt which was continuously developing in the barrel as the piston moved down the barrel.…”

supporting

confidence: 91%

“…Rawal and Davies 14 used a rotating square die to produce polyethylene net structure from an extrusion process, and found that the shape of the extruded PE filament using the rotating die deviated from its corresponding die at the die exit. Ma et al 15,16 experimentally and theoretically investigated a forward extrusion of pure lead using rotating conical dies, and suggested that the extrusion load was reduced by die rotation. The molten lead exhibited a twisted flow at a finite distance from the punch, and the twisting level became larger and deeper by increasing the die rotating speed.…”

Section: Introductionmentioning

confidence: 99%

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A die rotating system for moderations of extrusion load and pressure drop profiles for molten PP and wood/polypropylene composites in extrusion processes

Intawong

Kantala

Lotaisong

et al. 2010

J of Applied Polymer Sci

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A die-rotating system was proposed in this work for moderations of extrusion forces and entrance pressure drop for molten polypropylene (PP) and wood/ polypropylene (WPP) composites in a capillary rheometer and a single screw extruder. The effects of processing conditions and wood loading in PP were of our interests. The extrusion force and entrance pressure drop with and without the die rotating system were monitored in real-time. This was the first time that the die-rotating system was used for processing of highly viscous wood/polymer composite materials. It was found that the flow properties of the molten PP and WPP composites obeyed pseudoplastic non-Newtonian behavior. The behavior was more obvious at wood contents of above 6 wt % and in the capillary rheometer. The rotation of the die could moderate the extrusion load by 60% and entrance pressure drop by 20% in the capillary rheometer, and the entrance pressure drop by 30% in the single screw extruder, especially at the conditions where the viscosities of the WPP and the extrusion rate were high. Greater fluctuations in entrance pressure drop caused by die rotation were observed in the single screw extruder.

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supporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

A die rotating system for moderations of extrusion load and pressure drop profiles for molten PP and wood/polypropylene composites in extrusion processes

Intawong

Kantala

Lotaisong

et al. 2010

J of Applied Polymer Sci

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show abstract

“…Processing was performed in a few steps with material separation for short parts after each step. Shahbaz et al [92], Ma et al [93], and Li et al [94] suggested different concepts for introducing additional strains during one step extrusion using, respectively, spiral conical dies, rotating conical dies, multi-step dies, and so forth. These dies provide only moderate improvements at the laboratory scale and did not find further developments as techniques of SPD.…”

Section: Spd By Ordinary Forming Operationsmentioning

confidence: 99%

Review: Modes and Processes of Severe Plastic Deformation

Segal¹

2018

Preprint

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In this review, severe plastic deformation (SPD) is considered as a materials processing technology. The deformation mode is the principal characteristic differentiating SPD techniques from common forming operations. For large plastic strains, deformation mode depends on the distribution of strain rates between continuum slip lines and can be varied from pure shear to simple shear. A scalar, invariant and dimensionless coefficient of deformation mode is introduced as a normalized speed of rigid rotation. On this basis, simple shear provides the optimal mode for structure modification and grain refinement whereas pure shear is "ideal" for forming operations. Special experiments and SPD practice confirm this conclusion. Various techniques of SPD are classified and described in accordance with simple shear realization or approximation. It is shown that correct analyses of the processing mechanics and technological parameters are essential for comparison of SPD techniques and the development of effective industrial technologies.

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“…The ductility enhancement of the ECA-extruded Mg alloy was related to an unusual texture, where the basal planes were highly inclined ($45 ) from the extrusion direction axis. 6) Recently, authors newly focused on torsion extrusion [7][8][9][10][11][12] as another shear extrusion process. The schematic view of torsion extrusion is shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

“…The torsion extrusion has been proposed in order to reduce an extrusion load and accumulate a plastic strain in metals. [7][8][9] Mizunuma 10,11) revealed that the accumulation of plastic strain by torsion extrusion was an effective method for grain refinement of commercial Mg alloys. Furthermore, authors 12) revealed that a commercial Mg alloy (Mg-Al-Zn alloy) torsion-extruded at 523 K tended to produce a unique texture with h10 1 10i direction inclined 30 from the extrusion direction, resulting in significant enhancement of tensile ductility.…”

Section: Introductionmentioning

confidence: 99%

Texture and Mechanical Properties of Mg-3Al-1Zn-0.5Mn-1.5Ca Alloy Produced by Torsion Extrusion

et al. 2010

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Torsion extrusion was carried out on Mg-3Al-1Zn-0.5Mn-1.5Ca (in mass%) alloy (AZ31+1.5Ca alloy). The annealed torsion-extruded AZ31+1.5Ca alloy exhibited higher elongation compared with the annealed extruded AZ31+1.5Ca alloy without torsion. The ductility enhancement was attributed to a unique texture with h10 1 10i direction inclined 30 from the extrusion direction and low pole density. Besides, the annealed torsion-extruded AZ31+1.5Ca alloy exhibited higher strength compared with the annealed torsion-extruded Mg-3Al-1Zn-0.5Mn (in mass%) alloy (AZ31 alloy). In the extruded AZ31+1.5Ca alloy, the fine second phase particles, which contributed to a suppression of the grain growth during extrusion and annealing, were observed. The enhanced strength of the annealed torsion-extruded AZ31+1.5Ca alloy was likely attributed to not only grain refinement but also strengthening by the presence of the second phase particles.

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Forward extrusion through steadily rotating conical dies. Part I: experiments

Cited by 51 publications

References 7 publications

A die rotating system for moderations of extrusion load and pressure drop profiles for molten PP and wood/polypropylene composites in extrusion processes

A die rotating system for moderations of extrusion load and pressure drop profiles for molten PP and wood/polypropylene composites in extrusion processes

Review: Modes and Processes of Severe Plastic Deformation

Texture and Mechanical Properties of Mg-3Al-1Zn-0.5Mn-1.5Ca Alloy Produced by Torsion Extrusion

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