Numerical and experimental study on the extrusion through a porthole die to produce a hollow magnesium profile with longitudinal weld seams

The present study focuses on the feasibility of non-destructive testing methods for the detection of transverse and longitudinal weld seams in extruded aluminum alloys. Two extrusion trials using billet on billet extrusion with a porthole die producing both types of weld seams were conducted. First, two billets of different types of alloy, AlMgSi1 (EN AW-6082) and AlZn4.5Mg1 (EN AW-7020), were extruded. In a second trial, two billets of AlZn4.5Mg1 were processed. The produced profiles were then tested by non-destructive testing using a tactile eddy current sensor as well as an encasing sensor at room temperature. The measured signals of both sensors were then evaluated and compared. Microstructural analyses have been carried out to correlate the occurrence of transverse and longitudinal weld seams with the results of the non-destructive testing.

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Analysis of Metal Flow through a Porthole Die to Produce a Rectangular Hollow Profile with Longitudinal Weld Seams

Advances on Extrusion Technology and Simulation of Light Alloys - Key Engineering Materials ◽

10.4028/0-87849-467-7.145 ◽

2008 ◽

pp. 145-152

Author(s):

Gang Liu ◽

J. Zhou ◽

K. Huang ◽

J. Duszczyk

Keyword(s):

Metal Flow ◽

Porthole Die ◽

Flow Through ◽

Weld Seams

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Interfacial structure and bonding mechanism of weld seams during porthole die extrusion of aluminum alloy profiles

Materials Characterization ◽

10.1016/j.matchar.2018.01.052 ◽

2018 ◽

Vol 138 ◽

pp. 56-66 ◽

Cited By ~ 16

Author(s):

Junquan Yu ◽

Guoqun Zhao

Keyword(s):

Aluminum Alloy ◽

Interfacial Structure ◽

Bonding Mechanism ◽

Porthole Die ◽

Structure And Bonding ◽

Die Extrusion ◽

Porthole Die Extrusion ◽

Weld Seams

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Investigation on longitudinal weld seams during porthole die extrusion process of high strength 7075 aluminum alloy

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-016-9902-8 ◽

2016 ◽

Vol 91 (5-8) ◽

pp. 1897-1907 ◽

Cited By ~ 8

Author(s):

Gaojin Chen ◽

Liang Chen ◽

Guoqun Zhao ◽

Bing Lu

Keyword(s):

Aluminum Alloy ◽

High Strength ◽

Extrusion Process ◽

7075 Aluminum Alloy ◽

Porthole Die ◽

Die Extrusion ◽

Porthole Die Extrusion ◽

Weld Seams

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Microstructural Stability of Extruded Mg-Mn-Ce Hollow Profiles with Weld Seams

Metals ◽

10.3390/met11040547 ◽

2021 ◽

Vol 11 (4) ◽

pp. 547

Author(s):

Felix Gensch ◽

Sven Gall ◽

Stefan Lechner ◽

Christoph Fahrenson ◽

Soeren Mueller

Keyword(s):

Weld Seam ◽

Strong Dependence ◽

Heat Treatments ◽

Fiber Texture ◽

Extrusion Ratio ◽

Microstructural Stability ◽

Subsequent Aging ◽

Porthole Die ◽

Free Material ◽

Weld Seams

Despite aluminum profiles, magnesium profiles have not been well developed due to the low formability. Furthermore, extruded magnesium profiles show a strong dependence on the mechanical properties, according to the loading direction. This is caused by a strong basal texture, which is directly dependent on the process parameters during the extrusion and the subsequent aging. Thus, the present paper focuses on the analysis of the microstructure and its evolution of extruded magnesium hollow profiles, which were subjected to a series of heat treatments at 475 °C up to one hour. The hollow profiles were extruded through a porthole die, thus, containing longitudinal weld seams. These were formed by material that underwent heavy shearing along the tool surface based on the friction conditions in the porthole die. Three extrusion ratios (ER = 8:1, ER = 16:1, ER = 30:1) were applied, resulting in three different wall thicknesses of the profiles. The microstructure of the profiles was analyzed using light-optical microscopy (LOM) and scanning electron microscopy (SEM) coupled with electron backscatter diffraction (EBSD). The analysis revealed no change of the microstructure of the profiles extruded at the two higher extrusion ratios within the time frame of the heat treatment. In contrast, the microstructure and, thus, the micro-texture of the profile with the lowest extrusion ratio (ER = 8:1) has been affected to a great extent. While only small changes in microstructure in the weld-free area were observed, the initial microstructure in the weld seam was transformed from fine recrystallized grains into a significantly bimodal microstructure mainly due to an abnormal grain growth (AGG). These changes were accompanied by a promotion of the rare-earth (RE) texture component for the weld-free material and a change of the overall texture from RE to a typical non-RE double fiber texture for the weld seam due to the intense AGG within the short-time heat treatments. In addition, the influence of the extrusion ratio on particle size and distribution as well as the character of the microstructure governing the behavior during heat treatments was analyzed and discussed.

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Analysis of Metal Flow through a Porthole Die to Produce a Rectangular Hollow Profile with Longitudinal Weld Seams

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.367.145 ◽

2008 ◽

Vol 367 ◽

pp. 145-152 ◽

Cited By ~ 4

Author(s):

Gang Liu ◽

Jie Zhou ◽

K. Huang ◽

Jurek Duczczyk

Keyword(s):

Fe Simulation ◽

Metal Flow ◽

Three Dimensional ◽

Flow Patterns ◽

Fe Model ◽

Porthole Die ◽

Flow Through ◽

The Difference ◽

Weld Seams ◽

Deform 3D

A detailed analysis of metal flow through a porthole die to produce a rectangular hollow aluminium profile was performed by means of three-dimensional FE simulation using DEFORM 3D. It was aimed at revealing the flow patterns of a medium-strength aluminium alloy 7020 through a porthole die and gaining an insight into the formation of longitudinal weld seams inside the welding chamber during extrusion. In the case of extruding a rectangular hollow profile through a porthole die with four ports, two neighbouring ports were different from each other. Using an FE model including these two ports, different flow patterns of two individual metal streams were revealed. The 3D FE simulation also showed how two unequal metal streams contacted each other and became bonded in the welding chamber under a certain hydrostatic pressure and at a certain temperature, before the metal flew through the die bearing. The difference in velocity between the metal streams led to uneven flow at the die bearing and thus a wavy extrusion nose.

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Experimental study on the restoration from a tilt-azimuth series for improvement in resolution

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010013955x ◽

1995 ◽

Vol 53 ◽

pp. 636-637

Author(s):

Norio Baba ◽

Norihiko Ichise ◽

Syunya Watanabe

Keyword(s):

Experimental Study ◽

Spherical Aberration ◽

Incident Beam ◽

Optical Parameters ◽

Beam Tilting ◽

Illumination Method ◽

Restoration Method ◽

Illumination Mode

The tilted beam illumination method is used to improve the resolution comparing with the axial illumination mode. Using this advantage, a restoration method of several tilted beam images covering the full azimuthal range was proposed by Saxton, and experimentally examined. To make this technique more reliable it seems that some practical problems still remain. In this report the restoration was attempted and the problems were considered. In our study, four problems were pointed out for the experiment of the restoration. (1) Accurate beam tilt adjustment to fit the incident beam to the coma-free axis for the symmetrical beam tilting over the full azimuthal range. (2) Accurate measurements of the optical parameters which are necessary to design the restoration filter. Even if the spherical aberration coefficient Cs is known with accuracy and the axial astigmatism is sufficiently compensated, at least the defocus value must be measured. (3) Accurate alignment of the tilt-azimuth series images.

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