oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 362 )

2018 ( 518 )

2017 ( 535 )

2016 ( 764 )

Custom range...

Search Results: 1 - 10 of 325240 matches for " S. Kumai "
All listed articles are free for downloading (OA Articles)
Page 1 /325240
Display every page Item
High speed roll casting of Mg alloy strip by a vertical type twin roll caster
T. Haga,H. Watari,S. Kumai
Journal of Achievements in Materials and Manufacturing Engineering , 2006,
Abstract: Purpose: The possibility of high speed roll casting of AZ31, AM60 and AZ91 was investigated. Warm deep drawing of roll cast magnesium alloy was operated. and formability of roll cast magnesium strip was cleared.Design/methodology/approach: A vertical type high speed twin roll caster was used. The roll casting was operated in the air atmosphere. The casting speed was from 60 m/min up to 180 m/min. Low temperature casting was adopted to realize high speed casting.Findings: Strip thinner 3 mm with 100 width could be cast continuously. The casting ability became better with increasing content of Al. Roll cast Mg alloy strips could be hot-rolled down to 0.5 mm. AZ31 as-cast strip could be thinner down to 0.5 mm only by three times of hot rolling. Deep drawing was operated with three kinds of Mg alloy at 250°C, and LDR value was larger than 2.0. It was shown that deep drawing of AZ91 alloy for casting was possible.Research limitations/implications: There was tendency that cracks occurred at the center in the thickness direction as Al content increased.Practical implications: Sheet metal forming of magnesium alloy with high content Al can be realized.Originality/value: It was shown that possibility of high speed roll casting of magnesium alloy, and warm deep drawing of roll cast AZ91 strip.
Casting of aluminum alloy strip using an unequal diameter twin roll caster
T. Haga,H. Inui,H. Watari,S. Kumai
Archives of Materials Science and Engineering , 2008,
Abstract: Purpose: of this paper is to clear the property and ability of an unequal diameter twin roll caster to castcommercial size strip. Therefore, 400mm-width strip was cast as first step. Surface-condition, microstructure andmechanical property of the strip was investigated.Design/methodology/approach: Method used in the present study was an unequal diameter twin roll caster.This method was devised to realize easy operation of the twin roll casting and increase of casting speed.Findings: are that 400-width-strip of 3084, 5182 and 6022 could be cast at speed of 20 m/min. This strip wasabout 4 mm-thick. There were some defects on the surface. As cast strip could be cold-rolled down to sheetof 1 mm-thick. 180 degrees bending test was operated on the 6022 sheet after T4 heat treatment. Crack did notoccurred at the outer surface when strip was bent at width-direction.Research limitations/implications: is that the quantity of the melt was 21kg and investigation of theproperties was not enough for practical use. The larger weight of melt must be cast for production.Practical implications: are as below. The 400mm-width strip can be cast easily by the unequal diameter twinroll caster. This caster can be adapted to 3083, 5182 and 6022.Originality/value: as below. The economy sheet with 400mm width can be produced by the unequal diameter twinroll caster. 3083, 5182 and 6022 can be cast at the speed of 20m/min. The thickness of the strip was about 4mm.
Clad strip casting by a twin roll caster
T. Haga,R. Nakamura,S. Kumai,H. Watari
Archives of Materials Science and Engineering , 2009,
Abstract: Purpose: Of this paper is to realize the casting of the clad strip by only one process. Therefore, the investigation of the ability of the casting of the clad strip by a vertical type twin roll caster was operated. The aim of the use of the twin roll caster to make clad strip was in the reduction of the production-energy of the clad strip.Design/methodology/approach: Used in the present study was a vertical type twin roll caster with the scriber. The scriber was used to prevent the mixture of the two kinds of the melts. The scriber was set at roll-bite, and the scriber contacted to the one of solidification layer. The melt was stopped by the scriber and the only the solidification layer was dragged by the roll.Findings: The clad strip with the clear interface could be by the vertical type twin roll caster with the scriber. The scriber was useful to drag only the solid and semisolid layer. The two kinds of strips were connected strictly at the interface of the clad strip. The clad strip was not broken at the interface by the continuous bending.Research limitations/implications: Are that 100 mm width-strip was cast in the present study. Ability of the clad strip that is wider than 100 mm was not clear. The control of the clad ratio was not investigated.Practical implications: The twin roll caster devised and investigated in this report is useful to cast clad strip like the brazing sheet for the radiator of the automobile.Originality/value: The vertical type twin roll cater to cast clad strip is original process. The scriber was used to prevent the mixture of the two kinds of melts. The scriber was not used in the previous research to cast clad strip at the twin roll caster, and use of the scriber was the first try.
Grooved roll for a high speed twin roll caster
T. Haga,K. Hirooka,H. Watari,S. Kumai
Archives of Materials Science and Engineering , 2008,
Abstract: Purpose: Purpose of this paper is investigation of the effect of roll-surface on the strip-surface. Improvement ofsmall 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 withgrooved roll. Two kinds of grooves were used: one was parallel groove and the other was cross groove machinedby 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 stripsurface. The contact condition between the roll and the melt became uniform by the small groove on the rollsurface. 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 beerased 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-rolledin 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.
High speed twin roll casting of 6061 alloy strips
T. Haga,H. Sakaguchi,H. Watari,S. Kumai
Archives of Materials Science and Engineering , 2008,
Abstract: Purpose: of this paper is to clear the possibility of high speed roll casting of thin strips of two aluminum alloys:6061 and recycled 6061. Mechanical properties of the roll cast 6061 and recycled 6061 strips were investigated inthe frame of this purpose.Design/methodology/approach: Methods used in the present study were high speed twin roll caster and lowtemperature casting. These methods were used to realize rapid solidification and increase the casting speed.Findings: are that 6061 and recycled 6061 could be cast at speed of 60 m/min. Casted strips were about 3 mmthick. As cast strip could be cold-rolled down to sheet of 1 mm thick. 180 degrees bending test was operated on thesheet after T4 heat treatment and crack was not worse than 6022 which is typical aluminum alloy for sheet of theautomobile. This result means the roll cast 6061 can be used as a sheet for body of the automobile instead of 6022.Research limitations/implications: Research limitation is that the width of the strip was 100 mm andinvestigation of the properties were enough for practical use. Wider strip must be cast using the twin roll caster ofthe size for production.Originality/value: The economy sheet of the 6061 for the auto mobile can be produced by the high speed twinroll caster. 6061 is typical wrought aluminum alloy of 6000 series. Therefore, the sheet of 6061 will becomeeconomy. 6061 can be recycled at two times when the 6061 is cast into strip by the high speed roll casting.
Roll caster for the three-layer clad-strip
R. Nakamura,T. Yamabayashi,T. Haga,S. Kumai
Archives of Materials Science and Engineering , 2010,
Abstract: Purpose: of this paper is to show the characteristics of two kinds of roll casters for three-layer clad strip of aluminium alloys. Moreover, the characteristics of these twin roll casters were compeered with the early type of roll casters for clad strip.Design/methodology/approach: Design was tried to attain the fabrication of the roll casters to cast the three-layers-clad-strip. One caster was an unequal diameter roll caster equipped with a scraper. The scraper was adopted to prevent the mixture of different kinds of melts of the alloys. The scraper was used to cast the clad strip with clear interfaces between each strip. The other caster was a tandem type roll caster assembled from two vertical type twin roll casters. A vertical type of twin roll was mounted on the other vertical type of a twin roll caster.Findings: Three layers of clad strips could be cast by two kinds of the roll casters developed in the present study. The casting speed was 20 m/min. This speed was much higher at the conventional twin roll caster for the aluminium alloys. Each strip of three layers clad strip was connected strictly. The element of clad strip did not peel at the interface by continuous bending. The as-cast clad strip could be cold-rolled. The element of alloys did not mix at the connecting interface of the strips. The casting conditions which affected the connecting of the strips and condition of interface were investigated and shown in this paper.Research limitations/implications: The width of the strip was from 30 mm to 50 mm. The casting of the wide strip was not investigated. The alloy used in the present study was only aluminium alloys. The length of the cast strip was 3 m. The thickness of element strip was from 0.8 mm to 1.5 mm. The difference of the melting temperature of the alloys was within 50°C. The number of the layers was less than three layers.Practical implications: The roll caster invented in the present study can be used for the fabrication of the clad strip. The clad strip is, for example, used for the brazing sheet of the radiator for the automotive industry.Originality/value: There was not a report concerning the roll caster for three layers clad strip. The roll casters for clad strips shown in this paper were of an original process. Especially, the use of the scraper in the roll casting was original.
Strip casting using a single roll caster equipped with a scraper
T. Haga,K. Akitsu,K. Kamakura,S. Kumai
Journal of Achievements in Materials and Manufacturing Engineering , 2012,
Abstract: 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.
High speed twin roll casting of 6016 aluminium alloy strip
H. Sakaguchi,T. Haga,H. Watari,S Kumai
Journal of Achievements in Materials and Manufacturing Engineering , 2007,
Abstract: Purpose: of this paper is to clear the possibility of high speed roll casting of aluminum alloy strip. In the bodyof the automobiles, a sheet of 6016 aluminum alloy is adopted for the outer panel. Therefore, casting of 6016was 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 designedto 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 60m/min. Thethickness of the strip was 3.4 mm. The microstructure at as-cast and after T4 heat treatment was shown. Themicrostructure was very fine. The mechanical properties were investigated by the tensile test and 180 degreesvending test. The as-cast strip could be cold rolled without homogenization to 1mm. Result of tensile test wastensile strength was 230MPa, 0.2% proof stress was 118MPa and elongation was 33%. 6016 strip of T4 heattreatment 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 necessary to test twin roll casterequipped wide rolls.Practical implications: are as below. The mechanical properties of the roll-cast 6016 were enough for the sheetmetal for the automobile. The low productivity of the twin roll caster could be improved.Originality/value: is that 6016 strip could be cast continuously at speed 60 m/min and this strip had goodmechanical properties.
High speed twin roll casting of Al-3Si-0.6Mg strip
T. Haga,M. Ikawa,H.Watari,S.Kumai
Journal of Achievements in Materials and Manufacturing Engineering , 2006,
Abstract: Purpose: Purpose of this paper is to clear the possibility of high speed roll casting of thin strip of Al-3%Si-0.6%Mg alloy. Investigation of the mechanical properties of the roll cast 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 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 occurred at the outer surface.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 aluminum alloy will becomes easy. The content of Fe in the recycled aluminum 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 result means the roll cast Al-3%Si-0.6%Mg has ability to be used as the body sheet of the auto mobile.
High speed twin roll casting of recycled Al-3Si-0.6Mg strip
T. Haga,M. Ikawa,H. Watari,S. Kumai
Journal of Achievements in Materials and Manufacturing Engineering , 2007,
Abstract: 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 occurred 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 aluminum alloy will becomes easy. The content of Fe in the recycled aluminum 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 aluminum alloy sheet for the automobile.
Page 1 /325240
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.