Twin roll casting of magnesium alloys with high aluminum contents

• Autorzy: Watari H. , Haga T. , Shibue Y. , Davey K. , Koga N.
• Języki publikacji: EN

Abstrakty

EN

Purpose: The purpose of the work is to establish a manufacturing process and technology to facilitate the economical manufacture of high-quality magnesium sheet alloys with high aluminum contents, such as AZ61 and AZ91. The aim of the work is to establish a twin roll casting technology to facilitate the manufacture of AZ61 and AZ91 magnesium sheet alloys economically whilst maintaining high quality. Design/methodology/approach: A horizontal type twin roll caster was used to manufacture thin magnesium alloy sheets of AZ61 and AZ91. Pair of copper alloy roll and pure copper roll was used for the horizontal type twin roll caster. A closed type tundish was set to the roll caster to keep stable contact of molten magnesium with upper and lower rolls. Findings: The experiment results clarified that AZ61 and AZ91 sheets can be manufactured by twin roll casting process. The product sheet thickness in the present experiment is 2.0 to 4.5 mm for AZ91, 2.5 to 5.0mm for AZ61. Mill stiffness and a method of predicting the cast sheet’s thickness were investigated to determine the appropriate manufacturing conditions. The microstructure of AZ61 cast strips was equiaxed structure and the crystal sizes are different depending on cross section observed. The dendric and equiaxed microstructure were seen in the microstructure of AZ91 cross section. The intermetllic Mg17Al12 was seen in the grain boundary in AZ91 when roll speed was very slow. The grain size of the manufactured wrought magnesium alloys sheet was less than 10 micrometers. The obtained magnesium alloy sheet exhibited an equivalent limiting drawing ratio in a warm-drawing test. The limiting drawing ratio of AZ61 was 2.6 and 2.4 for AZ91. Research limitations/implications: The suitable roll speed was from 9m/min to 15m/min in manufacturing AZ91 and AZ61 strip using copper alloy rolls. When in use of pure copper roll, strips were cast between 6m/min and 20m/min for manufacturing AZ61 and AZ91. The superheats in the experiment were 15ºC and 30ºC. The cast strips should be hot rolled at 300ºC. Originality/value: value In this experiment, it is clarified that AZ61, AZ91 sheets can be manufactured by twin roll casting. These cast sheet can be hot rolled and the manufacturing process by twin roll casting enable to manufacure thin magnesium sheet alloys with high aluminum contents. It has been found that the manufactured cast AZ61 and AZ91 have good formability by a warm deep drawing test.

Słowa kluczowe

EN

casting; plastic forming; magnesium alloys; twin roll caster

PL

odlewanie; kształtowanie plastyczne; stop magnezu; odlewanie między rolkami

• Wydawca: International OCSCO World Press
• Czasopismo: Journal of Achievements in Materials and Manufacturing Engineering
• Rocznik: 2006
• Tom: Vol. 18, nr 1-2
• Strony: 419--422
• Opis fizyczny: Bibliogr. 3 poz., rys., tab.

Twórcy

autor

Watari H.

• Oyama National College of Technology, 771, Nakakuki, Oyama, 323-0806 Japan

autor

Haga T.

• Osaka Institute of Technology, 5-16-1 Omiya Asahiku Osaka, 535-8585 Japan

autor

Shibue Y.

• Toyohashi University of Technology, 1-1 Hibarigaoka, Tenpaku-cyo, Toyohashi, 441-8580 Japan

autor

Davey K.

• The Univerisity of Manchester, PO BOX 88 Sacville Street, Manchester, M60 1QD, United Kingdom

autor

Koga N.

• Nippon Institute of Technology, 4-1 Gakuen-dai, Miyashiro-machi, Minami saitama-gun, Saitama-ken, 345-850 Japan

Bibliografia

• [1] http://www.ulsab-avc.org/, ULSAB-AVC Results
• [2] H.Watari, K. Davey, M. T. Alonso Rasgado, T. Haga, Semi-solid manufacturing process of magnesium alloys by twin-roll casting, Journal of Materials Processing Technology, Vol. 155-156, 2004, p1662-p1667.
• [3] H.Watari, R. Paisarn, N. Koga, T. Haga. K. Davey, M.T.Alonso Rasgado, Forming characteristics of cast magnesium alloy sheets manufactured by roll strip casting process, Key Engineering Materials Vols. 274-276, 2004, p379-p384.