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1

Roll casting of a clad strip consisting of 5182 aluminium alloy

100%

Haga T.

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tom Vol. 73, nr 1

33--43

EN

Purpose: The investigation of the casting ability of the two layers and three layers clad strips consisting of the 5182 (Al-Mg) strip by the vertical type twin roll caster equipped with a scraper and the vertical type tandem twin roll caster at the speed higher than 30 m/min is one of the purposes. Another purpose is investigation of the casting conditions that affect the bonding condition of the 5182 strip to another aluminium alloy strip. Design/methodology/approach: A twin roll caster equipped with a scraper and a vertical type tandem twin roll caster were designed, assembled, and the castings of clad strips consisting the 5182 strip were tried. The interface between the strips were observed by the optical microscope. The bonding strength between strips was investigated by the continuous bending test. Findings: In the casting of the 5182 strip and the 3003 strip, the temperature of the 3003 strip influenced the bonding. When the temperature of the 3003 strip was lower, the 5182 strip was not bonded to the 3003 strip. In the casting of the 5182 strip and the 4045 strip, the porosity occurred near the interface. The temperature of the 5182 strip at the roll bite influenced the occurrence of the porosity. When the temperature of the 5182 strip was low, the porosity did not occur. The vertical type twin roll caster equipped with a scraper was suitable for the clad strip consisting of the 5182 and the 3003, and consisting of the 5182 and the 4045. The sound clad strips of the 5182 and the 3003, of the 5182 and 4045 could be cast using the vertical type twin roll caster equipped with a scraper. Research limitations/implications: The size of the roll was laboratory size. Moreover, the amount of the poured molten metal was less 3kg. Therefore, there was no information about the commercial size clad strip in this paper. Practical implications: The aluminium clad strip can be used to make component of the automobile by the press forming. Originality/value: The twin roll casters that could cast two and three layers clad strips were original invention. It is shown that the clad strips consisting of the 5182 (Al-Mg) strip could be cast using the twin roll caster. The elucidation of the casting conditions that affects the bonding and porosity near the interface is original result.

2

High speed twin roll casting of recycled Al-3Si-0.6Mg strip

51%

Haga T. , Ikawa M. , Watari H. , Kumai S.

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tom Vol. 21, nr 1

7-12

EN

Purpose: Purpose of this paper is to clear the possibility of high speed roll casting of thin strip of recycled Al-3%Si-0.6%Mg alloy. Investigation of the mechanical properties of the roll cast recycled Al-3%Si-0.6%Mg strip was purpose, too. Design/methodology/approach: Method used in the present study was high speed twin roll caster and low temperature casting. These methods were used to realize rapid solidification, and increase of casting speed. Findings: Findings are that recycled Al-3%Si-0.6%Mg was could be cast at speed of 60 m/min. This strip was 3.1 mm-thick. As cast strip could be cold-rolled down to sheet of 1 mm-thick. 180 degrees bending test was operated on the sheet after T4 heat treatment and crack was not occured at the outer surface. This result means the roll cast recycled Al-3%Si-0.6%Mg can be used as the body of the auto mobile. Research limitations/implications: Research limitation is that the width of the strip was 100 mm and investigation of the properties was not enough for practical use. Wider strip must be cast using the twin roll caster of the size for production. Practical implications: Practical implications are as below. The economy sheet for the auto mobile can be produced by the high speed twin roll caster. Al-3%Si-0.6%Mg can be used both the casting and plastic forming. Therefore, fractionation in the recycle of the aluminium alloy will becomes easy. The content of Fe in the recycled aluminium alloy increases. Fe becomes intermetallic of AlSiFe. Si for Mg2Si becomes deficient. 3%Si was enough for Mg2Si if AlSiFe was precipitated. Al-3%Si-0.6%Mg is suitable for recycle. Originality/value: The economy sheet of Al-3%Si-0.6%Mg can be made by the high productivity of the HSTRC. The result of this report contributes to make the economy aluminium alloy sheet for the automobile.

3

High speed twin roll casting of 6016 aluminium alloy strip

51%

Sakaguchi H. , Haga T. , Watari H. , Kumai S.

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tom Vol. 20, nr 1-2

495-498

EN

Purpose: of this paper is to clear the possibility of high speed roll casting of aluminium alloy strip. In the body of the automobiles, a sheet of 6016 aluminium alloy is adopted for the outer panel. Therefore, casting of 6016 was tried in this study. Characteristics of roll cast 6016 were investigated. Design/methodology/approach: was a high speed twin roll caster. The high speed twin roll caster was designed to overcome the low castability of the twin roll caster. Findings: are as below. 6016 alloy could be cast into the strip continuously at the speed of 60 m/min. The thickness of the strip was 3.4 mm. The microstructure at as-cast and after T4 heat treatment was shown. The microstructure was very fine. The mechanical properties were investigated by the tensile test and 180 degrees vending test. The as-cast strip could be cold rolled without homogenization to 1 mm. Result of tensile test was tensile strength was 230MPa, 0.2% proof stress was 118MPa and elongation was 33%. 6016 strip of T4 heat treatment could be bent 180 degrees without occurrence of crack at the outer surface or breaking. Research limitations/implications: is the width of the strip was 100 mm. It is necesarry to test twin roll caster equipped wide rolls. Practical implications: are as below. The mechanical properites of the roll-cast 6016 were enough for the sheet metal for the automobile. The low productivity of the twin roller caster could be improved. Originality/value: is that 6016 strip could be cast continuously at speed 60 m/min and this strip had good mechanical properties.

4

Grooved roll for a high speed twin roll caster

51%

Haga T. , Hirooka K. , Watari H. , Kumai S.

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2008

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tom Vol. 30, nr 2

117-120

EN

Purpose: Purpose of this paper is investigation of the effect of roll-surface on the strip-surface. Improvement of small cracks on the strip-surface was tried and effect of groove at the roll surface on the strip surface was shown. Design/methodology/approach: Method used in the present study was high speed twin roll caster with grooved roll. Two kinds of grooves were used: one was parallel groove and the other was cross groove machined by knurling and bite attached to a lathe. Findings: Findings of this research are that grooved roll was effective to eliminate the small cracks on the strip surface. The contact condition between the roll and the melt became uniform by the small groove on the roll surface. Contact area became small, and heat transfer between the melt and roll became small, too. As the result, chill structure did not become columnar, and crack did not occur. Groove pattern on the strip surface could be erased by the cold rolling. Research limitations/implications: Research limitation is that groove life could not be investigated. Practical implications: Practical implications are as below. The roll load was small and strip was not hot-rolled in a high speed twin roll caster. The grooved roll made strip-surface sound. Grooved 600mm width roll was tested, and usefulness of the grooved roll was shown. Originality/value: In the present study effect of the grooved roll on a high speed twin roll caster was investigated.

5

High speed twin roll casting of 6016 strip

51%

Haga T. , Ikawa M. , Watari H. , Kumai S.

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tom Vol. 18, nr 1-2

371--374

EN

Purpose: of this paper is to clear the possibility of high speed roll casting of thin aluminum alloy strip. 6016 aluminum alloy is used for sheet metal of the automobile. Therefore, casting of 6016 was tried in this study. Castability and characteristics of roll cast 6016 strip were investigated. Design/methodology/approach: was a high speed twin roll caster. The high speed twin roll caster was designed to overcome the low castability of the twin roll caster. Findings: are as below. The 6016 could be cast at speed of 60 m/min. The thickness of the 6016 was 3 mm. The microstructure at as-cast and after T6 heat treatment was shown. The microstructure was very fine by the effect of the rapid solidification. The mechanical properties were investigated by the tension test and 180 degrees bending test. The as-cast strip could be cold rolled down to 1 mm without homogenization. The result of tension test (gage length 50mm) of T4 strip was as below, tensile stress was 242 MPa, proof stress was 123 MPa and elongation was 26%. There was no crack at the outer surface of 180-degree-bent strip until contact. This shows the strip endure the hem forming. Research limitations/implications: is the width of the strip was 100 mm. The test using a large scale twin roll caster must be operated. Practical implications: are as below. The mechanical properties of the roll-cast 6016 were enough for the sheet metal for the automobile. The low productivity of the twin roll caster could be improved, and economy 6016 strip was able to produce. Originality/value: is that 6016 strip could be cast at speed 60 m/min and this strip had good mechanical properties.

6

Micro-forming of Al-Si foil

51%

Haga T. , Inoue K. , Watari H.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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tom Vol. 40, nr 2

115-122

EN

Purpose: of this paper is as below. The investigation of the ability of the cold micro-forming of non-metallic glass was purpose. The grain of the rapidly solidified aluminium alloy became fine. The aluminium alloy foil with fine grain was used, and the investigation of the micro-formability of this alloy was investigated. Moreover, increase of the forming speed was investigated. The increase of the forming speed was purpose of this study, too. Design/methodology/approach: The nozzle pressing melt spinning method was used to attain the rapid solidification of the non-metallic grass. The Al-14mass%Si, which is hyper eutectic but is close to eutectic, was used. The roll contact surface was formed by V-groove. The cold rolling was adopted for forming. The V-groove was machined at the roll surface. The micro-forming was operated at the cold work. Findings: Micro-forming of the crystal aluminium alloy was able by the cold work. The forming speed was 0.04S to form 10 ěm height. The forming speed could be drastically increased. Research limitations/implications: The angle of the V-groove, which was used in the present study, was only 60 degrees. The effect of the groove angle on the protrusion-height was not clear. The used material was only the Al-14mass%Si. Relationship between the material and protrusion-height was not clear. Practical implications: The die for the micro-forming of the resin could be made from economy material by the conventional cold rolling process at short time. Therefore, the mass production of the economy die for resin may be obtained. Originality/value: The micro-forming of the rapidly solidified non-metallic glass by cold work was original.

7

Strip casting using a single roll caster equipped with a scraper

45%

Haga T. , Akitsu K. , Kamakura K. , Kumai S. , Watari H.

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2012

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tom Vol. 55, nr 1

26--32

EN

Purpose: Purpose of this paper is to investigate the ability of a single roll caster equipped with a scraper. The purpose of the development of the single roll caster equipped with a scraper is casting of the strip without centre line segregation and porosity and with sound free solidified surface. The single roll caster can cast the strip without the centre segregation and porosity. However, the conditions of the free solidified surface and the thickness distribution are not sound. The scraper was adopted in order to improve the free solidified surface. Investigation of the effect of the scraper and the properties of the roll cast strip is the purpose of this paper. Design/methodology/approach: A scraper was developed to improve the free solidified surface condition. The scraper scribed the semisolid metal on the free solidified surface to make the free solidified surface flat. The scraper was made from mild-steel-plate, and it was coated by the insulator sheet of 2 mm-thick. The scraper was pushed to free solidified surface by the constant load. Findings: The scraper was very useful to improve the free solidified surface. AA5182 aluminium alloy strip could be cast at the speed up to 40 m/min. There was no centre segregation and porosity. There was no difference between the roll contact surface and the scribed surface. The mechanical properties of the roll cast strip were as same as those of strip made from D.C. cast slab. Hi-content Al-Mg alloy like Al-10 mass%Mg, which cannot be cast into the strip by the twin roll caster without centre segregation, could be cast into the strip without defect. Research limitations/implications: Metal which was investigated was only aluminium alloy. It is not clear that this process is useful to other alloys like steel, copper et. al. Practical implications: This process may be able to be used instead of the D.C. casting and the twin roll casting. Especially, this caster is useful the strip casting of the Al-Mg alloy. Originality/value: The single roll caster equipped with a scraper is original development. This caster may be useful for aluminium and magnesium sheet making companies.

8

Twin roll casting of magnesium alloys with high aluminum contents

45%

Watari H. , Haga T. , Shibue Y. , Davey K. , Koga N.

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tom Vol. 18, nr 1-2

419--422

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.

9

Roll casting of 5182 aluminium alloy

38%

Haga T. , Mtsuo M. , Kunigo D. , Hatanaka Y. , Nakamuta R. , Watari H. , Kumai S.

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tom Vol. 34, nr 2

172-179

EN

Purpose: of this paper is investigation of the ability of the high speed roll casting of 5182 aluminium alloy. Appropriate twin roll caster to cast the 5182 strip was researched. Design/methodology/approach: Method used in the present study was an unequal diameter twin roll caster and a vertical type high speed twin roll caster equipped with mild steel rolls without parting material. Findings: are that the vertical type high speed twin roll caster was effective to cast 5182 strip at high speed. 5182 could be cast at 10 times higher speed than a conventional twin roll caster for aluminium alloy. 5182 could be cast by the mild steel roll using no-parting material without sticking. Research limitations/implications: is that ability of casting of the wide strip, that is wider than 600 mm, could not be investigated. Practical implications: 600 mm-width 5182 strip could be cast and this width is enough for some structural parts. 5182 could be cast into the strip at high productivity and low energy using the economy equipment and no-consumable good. Originality/value: The method to make economy sheet metal of aluminium alloy is imported. The economy alloy and economy process are essential to get economy aluminium alloy sheet.

10

Development of manufacturing process of wrought magnesium alloy sheets by twin roll casting

38%

Watari H. , Paisarn R. , Haga T. , Noda K. , Davey K. , Koga N.

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tom Vol. 20, nr 1-2

515-518

EN

Purpose: The purpose of the work is to development of a strip casting technology for manufacturing magnesium alloy sheets. The aim of the work is to establish a manufacturing process and technology to facilitate the economical manufacture of high-strength magnesium sheet alloys. Design/methodology/approach: A horizontal type twin roll caster was used to manufacture magnesium alloy sheets. Pair of copper alloy roll, pure copper roll and steel roll was used for the horizontal type twin roll caster. The diameter of the rolls was 300 mm and the width of rolls was 100 and 150 mm. Findings: The magnesium alloy sheets could be successfuly manufactured by the horizontal twin roll caster. The product sheet thickness in the present experiment was 2.0 to 5.0 mm. The equiaxed microstructure was observed in cast magnesium alloys when a pair of copper and copper alloy rolls were used. The mean grain size of the cast magnesium alloys strip was from 30 to 60 micrometers. After hot rolling process, the grain size was reduced to about 10 micrometers. The obtained magnesium alloy sheet indicated a good plastic formability by a warm-drawing test. Research limitations/implications: The superheat in the experiment was between 15 and 30 degrees centigrade, also an appropriate hot rolling temperature was 250 degrees centigrade for AZ31, AZ61 and AM60, 300 degrees centigrade for AZ91. Practical implications: The proposed manufacturing process was effective from the view point of economical manufacturing process as well as of formation of rapid solidification microstructures. Introducing the twin roll casting technology enable to manufacture magnesium sheet alloys with high aluminium contents, such as AZ61, AM60 and AZ91. Originality/value: AZ31, AM60, AZ61 and AZ91 wrought magnesium alloy sheets can be manufactured economically by twin roll casting. These cast sheet can be hot rolled and the proposed manufacturing process enables manufacturer to manufacture thin magnesium alloy sheets with high aluminium contents such as AM60, AZ61 and AZ91.