Property Oriented Wire Rolling Technology for Mg-Al Alloys

Ullmann

Kawalla

et al. 2021

MSF

Self Cite

Since 2018, the institute of metal forming has been studying the novel twin-roll casting (TRC) of magnesium wire at the pilot research plant set up specifically for this purpose. Light microscopic and scanning electronic investigations were carried out within this work and show the unique microstructure of twin-roll cast AZ31 magnesium alloy with grain sizes of about 10 μm ± 4 μm in centre and 39 μm ± 26 μm near the surface of the sample. By means of a short heat treatment (460 °C/15 min), segregations can be dissolved and grain size changes in centre to 19 μm ± 12 μm (increase) and near the surface to 12 μm ± 7 μm (decrease). Further, the mechanical properties of the twin-roll cast and heat-treated wire were analysed by tensile testing at room temperature. By heat treatment, the total elongation could be increased by a third whereas the strength decreases slightly. In heat-treated state, no preferred orientation is evident. In addition to the twin-roll cast and the heat-treated condition, the rolled state was analysed. For this purpose, the twin-roll cast wire was hot rolled using an oval-square calibration. After hot rolling, a dynamic recrystallization and grain refinement of the twin-roll cast wire could be achieved. It can be seen, that an increase in strength as well as in total elongation occur after wire rolling. Beside this, a rolling texture is evident.

Section: Introductionmentioning

confidence: 99%

Improving Mechanical Properties of Twin-Roll Cast AZ31 by Wire Rolling

Ullmann

Kawalla

et al. 2021

MSF

Self Cite

“…Magnesium wrought alloys are applied in form of sheets or plates in aerospace and automotive sector [2]. In addition, magnesium long products like bars and wires are industrially used for welding and joining processes or biomedical applications [3,4].…”

Section: Introductionmentioning

confidence: 99%

“…Though, extrusion processes are limited in length and size as well as not applicable for a mass production due to a currently high magnesium price [1]. A large-scale application and a lower price for magnesium could be possible by means of calibre rolling because there are no limits to product length [3]. Further, rolling in calibre leads to a finer microstructure [7][8][9] and superior mechanical properties in comparison to conventional manufacturing routes [10].…”

Section: Introductionmentioning

confidence: 99%

“…Further, rolling in calibre leads to a finer microstructure [7][8][9] and superior mechanical properties in comparison to conventional manufacturing routes [10]. Unfortunately, there are only few reports with respect to calibre rolling of magnesium alloys with a higher aluminium content like AZ80 [3], which would be suitable for a high-strength application.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Impact of Initial State during Calibre Rolling: Investigating Microstructure and Mechanical Properties of AZ80 Magnesium Alloy

Luft

Ullmann

et al. 2018

MSF

Self Cite

In order to investigate the effect of rolling on microstructure and mechanical properties of different initial states, cast and extruded magnesium alloy AZ80 bars were rolled in calibre. The microstructural characterization was done by light microscopy. As a result, the initial grain size of the cast AZ80 (66 μm) clearly differs from the extruded bar (13 μm). After 14 passes of hot rolling in calibre, a significant grain refining effect was achieved resulting in grain sizes of 5 μm for the cast and 3 μm for the extruded material. To investigate the mechanical properties in the initial and rolled state, tensile tests of both conditions were conducted at room temperature. Due to grain refining, the tensile strength (162 MPa) and the elongation (3 %) of cast AZ80 increased remarkably during 14 passes of calibre rolling (360 MPa and 19 %). The strengthening effect was also evident for the rolled extruded AZ80. However, the cast material exhibited cracks during calibre rolling due to its inexpedient microstructure for a high deformation calibre. On the contrary, the extruded AZ80 was easily deformable. This shows the clear impact of initial states on aspired end properties of processed materials. Future investigations will deal with developing a suitable calibration for cast AZ80.

“…As welding wire should correspond to the base material, a need for magnesium welding wires in form of different alloys arises as there are innovative development trends regarding wrought magnesium alloys for sheets and profiles [9]. Another potential field of application in the same sector are joining elements for magnesium components, e.g., magnesium bolts and screws [10].…”

Section: Potential Application Fieldsmentioning

confidence: 99%

Development of an Innovative and Quality-Focused Production Technology for Magnesium Wire

Kawalla²,

Kawalla

et al. 2018

MSF

Self Cite

Abstract. In order to meet customer requirements, technology developments need to stay focused at process rationalization and quality improvements. Combining the twin-roll casting technology and caliber rolling technology for magnesium wire, customer demands concerning cost-efficiency and high quality could be satisfied. For this purpose, the paper analyzes potential application fields and their demanded quality properties. Special requirements of illustrative magnesium long products are shown by adapting existing specifications of aluminum wire. The resulting long products could be applied in the automotive industry and aircraft sector as joining and welding elements or in biomedicine as screws. Finally, the innovative magnesium wire production technology will be explained and the advantages, in particular the resource efficiency, of the developed technology will be discussed.