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Al-4.7%Mg alloy with 0, 0.2, 0.4, 0.6 and 0.8% Fe added was cast using a copper mold and an insulator mold. The cooling rates of ingots cast using the copper mold and the insulator mold were 30.6 °C/s and 0.5 °C/s, respectively. The tensile stress and elongation of the ingots cast by the copper mold were superior to those cast by the insulator mold. The addition of Fe did not lead to tensile stress, but the elongation became smaller as the Fe content increased. The elongation of the ingot cast using the copper mold became much smaller on addition of only 0.2% Fe. The tensile stress and elongation were improved by hot forging with 50% reduction. The elongation of the ingots with Fe added was significantly improved by the hot forging. The degree of improvement of the tensile stress and elongation for the ingots cast using the insulator mold was remarkable.

A thin aluminum rod (width: 5 mm) was cast using a twin-wheel caster equipped with rotating side-dam plates. The upper and lower casting wheels were made of copper. The width of the flat upper and lower casting wheels was 5 mm. The rotating side-dam plate was made of mild steel. Paper 0.5 mm thick was pasted onto the plate. Boron nitride was sprayed onto the paper as an insulator and lubricant. A 6061 aluminum alloy thin rod could be cast continuously at casting speeds of 4 and 5 m/min. Molten metal was poured onto the lower wheel from a launder and conveyed into a square gap made by the lower wheel, upper wheel, and side-dam plates. The cross section of the cast rod was rectangular. The cross-sectional area of the rectangular rod was 12 to 15 mm2.

The aluminum alloy Al–5%Mg–2%Si, the chemical content of which is close to that of the Magsimal-59 aluminum alloy commonly for die casting, was successfully cast into strips using a vertical high-speed twin-roll caster at a speed of 30 m/min. This means that Al–5%Mg–2%Si is suitable for the high-speed twin roll-casting. The as-cast Al–5%Mg–2%Si strip was then successfully cold-rolled to a thickness of 0.7 mm. Tension and cup tests were conducted on the cold-rolled annealed strips. The tensile stress was 205 MPa and the elongation was 20% for a thickness of 1 mm. The limiting drawing ratio was 2.0 at a 0.7 mm thickness. The present results demonstrates that Al–5%Mg–2%Si can be used for die casting and sheet forming. This means that use of this alloy for both sheet forming and die casting could eliminate the need for the separation of wrought aluminum alloys from cast aluminum prior to processing at recycling plants.

Casting of a thin aluminum alloy strand was investigated using two-and three-wheel casters. Molten metal was poured through a launder into a trapezoidal groove in the lower wheel of the caster. In the two-wheel caster, the level of molten metal was lower than the height of the walls of the lower wheel groove, and a puddle was formed between the lower and upper wheels. As a result, it was possible to cast the strand without the formation of burrs. In the three-wheel caster, the level of molten metal was higher than the height of the walls of the lower wheel groove by effect of surface tension. However, with the use of a grooved first upper wheel, the molten metal became semisolid, and it was possible to cast the strand without burrs as this semisolid metal passed under the second upper wheel.

This study investigated the crystallization position and formation mechanism of globular crystals at the center area in the thickness direction of aluminum alloy strips cast by a high-speed twin roll caster. Twin roll casters for single strips and clad strips were used, as well as twin roll casters equipped with a cooling slope. The globular crystals were formed from dividing arms of dendrites of the solidified layer facing the center area at the roll gap. The arms of isolated dendrite also divided. No globular crystals were formed at the interfaces of clad strips with different solidification temperatures because of the temperature gradient at the interface which inhibited division of the dendrite arms. It was demonstrated that globular crystals at the center area of the thickness direction were formed by dendrite-arm-dividing at the roll gap by the strip casting clad strip. Experiments by semisolid-strip casting with the cooling slope showed that globular crystals in the molten metal existed in the solidification layers.

Al-Mg alloy strips were cast by an unequal-diameter twin-roll caster. It was found that cracks formed on the surface at grain boundaries. The grains near the surface were small in size, which likely contributed to crack formation. The use of a molten metal pouring method to increase the grain size near the surface is proposed to reduce cracks. In the previous method, molten metal is poured into a pool, which is on the lower roll surrounded by side-dam plates, a back-dam plate, and the upper roll. In this study, molten metal was directly poured onto the roll surface at a shallow angle using a launder. When the angle was smaller than 20°, cracks did not form. With the proposed method, the heat transfers between the molten metal and the roll surface decreased, as determined from the grain size and strip thickness. The cracks on the strip surface were color-checked and visually inspected.

Si ranging from 0.2 mass% to 2.0 mass% was added to Al-5%Mg alloy (5182) and strip was cast by a vertical type high-speed twin-roll caster at a speed of 80 m/min. The as-cast strip was cold-rolled down to 1 mm thickness and annealed. The mechanical properties were investigated using cup tests and tension tests. The limiting draw ratio (LDR) of the 5182 alloy was 2.0 and the LDR became smaller as the Si content increased. When the Si content was 2.0 mass%, the LDR was 1.8, which shows that Si-added 5182 can be used for sheet forming, if the Si content is less than 2.0 mass%. The tensile strength and elongation were almost constant when the Si content was less than 1 mass%, but decreased at 2.0 mass% Si. However, the elongation was greater than 20% at 2.0 mass% Si. For die casting, 2.0 mass% Si was determined as the appropriate content from the results of the tension tests. When the Si content is in the range from 1.0 mass% to 2.0 mass%, then the Si added Al-5%Mg has the ability to be used for both die casting and sheet forming.

The fluidity of pure aluminum and Al-Si alloys was investigated for casting thin products using a spiral die in die casting. An aluminum alloy with good fluidity can be die-cast into thin products. For a Si content of less than 6 mass%, the fluidity increased with decreasing Si content. For a Si content of greater than 6 mass%, the fluidity increased with increasing Si content. The fluidity was affected by latent heat, flowability in the semisolid state, and heat transfer between the die and metal. For pure aluminum, the latent heat is small and there is no semisolid state. However, pure aluminum has excellent fluidity because the heat transfer between the die and metal is small. For Al-25%Si, the latent heat is very large and flowability increases in the semisolid state. Therefore, the fluidity of Al-25%Si is high. Fluidity typically increases with increasing die temperature. The increase in fluidity due to an increase in die temperature for the pure aluminum is small compared with that for hypoeutectic Al-Si alloys. This means that the heat transfer between the pure aluminum and the die is smaller than that for hypoeutectic Al-Si alloys. Therefore, the influence of die temperature on the fluidity of the pure aluminum is small. It is estimated that the chill layer of the pure aluminum rapidly peels from the die, decreasing the heat transfer between the pure aluminum and the die.

An unequal diameter twin-roll caster equipped with a channel scraper is proposed to improve center-line segregation. A semisolid metal layer was made by the channel scraper on the upper side of the strip and solidified by an upper roll. The twin-roll caster cast a strip of 5182 with equiaxed grain and without center-line segregation at a speed of 30 m/min and a unit roll load of 104 N/mm. The tensile stress and elongation after cold rolling and annealing were 294 MPa and 28%, respectively.

A single-roll caster equipped with two scrapers and an unequal-diameter twin-roll caster equipped with two scrapers are proposed for casting clad strip without centerline porosity or segregation. A...

This paper describes direct cladding of magnesium (Mg) and aluminum (Al) alloys using a tandem horizontal twin roll caster that has three pairs of upper and lower rolls. Manufacturing conditions that are appropriate for fabricating Al/Mg and Al/Mg/Al cladded material were investigated. The surface condition of the cladded cast strip was examined. An electron probe micro analyzer was used to observe the interface between Al alloy and Mg alloy. The thickness of the mixed layer of Al and Mg alloy was 15μm, and how the materials were connected was clarified. Microscopic observation and backscattered electron analysis were used to investigate the cladding mechanisms of the Al and Mg alloy layers. Average hardness was determined using the Vickers hardness test at the Al layer and at the diffused layer between Mg and Al alloys. Cladding of Al/Mg alloy and A/Mg/Al alloy was possible using a tandem twin-roll caster. In addition, Al3Mg2 and Al12Mg17 phase precipitation at the interface of the Al and Mg alloys was confirmed during direct cladding from molten metals.

A vertical type tandem twin roll caster equipped with a scraper for the clad strip was invented. This roll caster could cast three layers clad strip which base strip had lower melting point than that of the overlay strips. The base strip was cast by an upper twin roll caster and the overlay strips were cast by a lower twin roll caster. The scrapers were attached to the lower twin roll caster, and were innovated to cast this type of three layers of clad strip. Solidification layers those became the overlay strips were pulled from between the scraper and the roll. The melt of the alloy which was as same as the base strip was poured between the scraper and the base strip. This melt connect the overlay strip and the base strip. The base strip was not re-melted. The scraper enabled that the solidification layer of the overlay strip contact to the melt of the base strip without mixing of the melt of the base and overlay strip. In this way, the sound three layers clad strip which base strip had lower melting point than that of the overlay strip could be cast by the vertical type tandem twin roll caster equipped with a scraper.

The purpose of the present study is to investigate the mechanical properties of roll cast recycled 6016 aluminum alloy strip using a vertical type high-speed twin roll caster. A vertical type twin roll caster with 1500 mm diameter rolls was designed and assembled to cast aluminum alloy strip at a high speed and high cooling rate. 6016 aluminum alloy sheet is typically used for the bodies of automobiles. Virgin 6016 (0.16 %Fe) and Fe added 6016 (0.45 %Fe) (henceforth called recycled 6016) alloys were cast at a speed of 60 m/min. The microstructure of the as-cast strip was observed. The as-cast strip could be cold rolled, without homogenization, down to 1 mm. Tension test and 180-degree bending test were conducted to investigate the properties of recycled 6016. The strip could be cast at a speed of 60 m/min. The thickness of the as-cast strip was 3.4 mm, and the microstructure was very fine. The as-cast strip could be cold rolled, without homogenization, down to 1 mm. T4 heat-treated strips of virgin 6016 (0.16 %Fe) and recycled 6016 (0.45 %Fe) alloys could be bent at 180 degrees without breaking. The Fe content had no effect on the results of the tension test and 180-degree bending test. The mechanical properties of recycled 6016 strip were improved by rapid solidification of the twin roll caster. The twin roll caster decreased the effect of Fe.

Strip casting of Al-25%Si strip was tried using an unequal diameter twin roll caster. The diameter of the lower roll (large roll) was 1000mm and the diameter of the upper roll (small roll) was 250mm. Roll material was mild steel. The sound strip could be cast at the speeds ranging from 8 m/min to 12 m/min. The strip did not stick to the roll without the parting material. The primary Si, which existed at centre area of the thickness direction, was larger than that which existed at other area. The size of the primary Si was smaller than 0.2 mm. Eutectic Si was smaller 5μm. The as-cast strip was ranging from 2mm to 3mm thick and its width was 100mm. The as-cast strip could be hot rolled down to 1mm. The hot rolled strip was cold rolled. The primary Si became smaller and the pore occurred around the primary Si after the rolling.

Roll caster to cast a three layers clad strip was invented and effect of casting conditions on the clad strip was investigated. Two vertical type twin roll casters were set at vertically tandem position to cast three layers clad strip. Roll speed, roll load (separating force), melt temperature and elements of the aluminum alloy were chosen as the experimental conditions to be investigated. The roll load (separating force) and elements of aluminum alloy were important factors to cast sound clad strip. The clad strip could be cast at the speeds up to 40m/min. Interface between the strips were clear and elements of each strip did not diffuse to other strip. The clad strip was not peeled off at the interfaces by continuous bending. Strips were strictly connected at the interfaces.

A single roll caster equipped with a scraper was devised to cast the strip with sound free solidified surface. A property of this single caster is equipment of the scraper. Semisolid metal on the free solidified surface was scribed by a scraper and the surface became flat. Center line segregation did not occur as the strip was solidified from single side. The AA5182 aluminum alloy could be cast at speeds up to 40m/min. Thickness was about 3mm. Pressure of the unit width from the scraper was ranging from 0.1N/mm to 1.0N/mm, and these pressure was enough to make the free solidified surface flat. Roll cast strip could be cold rolled down to 1mm. There was not difference between roll contact surface and the free solidified surface after cold rolling by a visual examination. Result of tension test of the roll cast strip was as same as that of D.C. cast and rolled strip. Deep drawing test was operated at the conditions both of the roll contact surface and the free solidified surface was outside. LDR (limited drawing ratio) was same at both conditions and they were 1.8. Thickness of the strip was controlled by the roll speed, solidification length (length of the melt pool) and pressure of the scraper. The single roll caster is simpler than a twin roll caster. Rigidity for rolling was not needed for the single roll caster. Cost of the roll is half comparing a twin roll caster. The equipment cost of the single roll caster is more economy than that of the twin roll caster.

High speed roll casting of AA5182 aluminum alloy was tried using a vertical type high speed twin roll caster equipped with mild-steel rolls. Parting material was not used and speed was 80m/min. AA5182 strip, which thickness was 2.1mm, could be cast continuously. However, porosity occurred at center area at the thickness direction of the strip of the as-cast strip. Si was added to original AA5182 to improve the porosity at 0.2, 0.4, 0.6, 0.8 and 1.0 mass%. The porosity was improved as the content of the Si increased. The elongation resulting from the tension test was the best when 0.2mass%Si was added. The clack on the surface was improved by the increase of the Si content. Roll casting ability was improved by the Si, too.

Roll casting of the model alloy of recycled AA5182 aluminum alloy was investigated. Fe up to 0.6% was added to the AA5182 to make the model alloys of recycled AA5182. Increase of 0.6% of Fe means that the recycle was three times operated. A vertical type high speed twin roll caster was used. Some devices were operated on the twin roll caster to increase the cooling rate in order to make impurity fine. The roll speed could be increased up to 80m/min. The roll-castability did not become worse by the addition of the Fe. The LDR (limiting Drawing Ratio) was 1.9 when the Fe addition was 0.6. The deterioration of the mechanical properties by the addition of impurity Fe was very small.

Strip casting process is possible to shorten for producing strip. Strip is produced from molten metal continuously and directly by strip casting process. Melt drag process is one of the single roll strip casting process. Melt drag process is simpler than general twin roll strip casting process. One of defect of cast strip is surface conditions, for example surface roughness. Cast strip surface roughness is larger than hot rolled strip. Large strip surface roughness is negative effect for cold rolling after strip casting or hot rolling. The aim of this study is improvement of cast strip surface roughness by melt drag process. We suggested vertical melt drag process. And investigations were operated such us producing conditions of Al-Si alloy strip, surface roughness of cast strip and microstructures.

A growing demand for lightweight products has been brought about by the rapid development of new automobiles in order to reduce fuel consumption, since the global environment conservation meeting at Kyoto. One of the keys to reduced fuel consumption is to utilize high-strength, light materials like stainless-steel, high-tensile strength steels and magnesium alloys, which are difficult to form due to their material characteristics compared to normal steel tubes. The purpose of this paper discuses the development of our new pressing technology that forms a relatively high-strength and light weight stainless-steel tube which is SUS436 with surface screw threads. Our new press-forming process was tested in order to obtain accurate screw threads on stainless-steel tubes. Finite element simulation and a 3-D digitizer were used to measure the accuracy of tubes manufactured by the proposed pressing method. It was proved from FEM simulation and a 3-D digitizer measurement that the proposed press-forming method decrease tube thickness more effectively than conventional roll-forming technology. As a result, the maximum decrease in material thickness produced by conventional roll-forming process was 40%, but the maximum decrease in material thickness produced by our press-forming process was 20%. Especially the processing by four outer dies and two inner dies is better as for material thickness than the processing by six outer dies and three inner dies.

Recently the growing demand for light weight products with high strength has been increased by the rapid development of automobile and aircraft technology. Also, reduction of carbon dioxide emissions is one of the most important issues also in the automobile industry. The weight reduction technology is important even if applied to electric vehicles rather than gasoline vehicles, as reduction of energy consumption is an important issue. Plastic processing of hollow pipes is an important technology for realizing weight reduction of automobile components. As an example of research into pipe forming there is the research by Ohashi et al. [1-2], who have carried out processing to enlarge pipe diameters using a lost core, which achieved suppressing reduction in wall thickness and greater pipe expansion than hydro forming. The authors investigated into a method of increasing the wall thickness of pipe by press forming. Using the finite element analysis method it was predicted that it is possible to increase the wall thickness of aluminum pipe with 2mm wall thickness by approximately 20% by hollow pipe press forming. Also, it was predicted that it is possible to increase the wall thickness by approximately 30% in places by eccentric pipe wall thickness increase. Also, the effect of the metal die which has a large effect on processing a pipe from a circular cylindrical shape to a rectangular tube shape was investigated.

Prior knowledge of local increase in sheet metal thickness due to forming of products would contribute to decreasing total product weight by giving the product designer an advance notice of the appropriate sheet metal thickness distribution in a product. A method using simulation to accurately predict such increases would greatly aid the designer in this task. The designer can then distribute thicker parts where a large area moment of inertia is needed from the viewpoint of structural strength in a given section. In terms of optical designing for variable thickness distribution in products, the sheet thickness in a product need not be considered constant. This paper presents the forming prediction during deep drawing. To clarify the mechanism of increase in sheet thickness, a 3-D forming simulation is performed during deep drawing by using the finite element method (FEM). The effects of tool shapes—angle of contact with the original material and the contacting length of the punch with the material—that mainly affect the change in thickness of the original material are investigated. The thickness distribution of drawn cups is measured for comparing the simulation results obtained by FEM with the experimental results. It is shown that controlling the distribution of sheet metal thickness is possible if the original material is relatively thick, and when an appropriate manufacturing method is selected.

In recent years global warming has become a worldwide problem. Reduction of carbon dioxide emissions is one of the most important issues also in the automobile industry. This weight reduction technology is important even if applied to electric vehicles rather than gasoline vehicles, as reduction of energy consumption is an important issue. Plastic processing of hollow pipes is an important technology for realizing weight reduction of automobile components. As an example of research into pipe forming there is the research by Ohashi et al. [1-2], who have carried out processing to enlarge pipe diameters using a lost core, which achieved suppressing reduction in wall thickness and greater pipe expansion than hydroforming. In this research, a method of increasing the wall thickness of pipe by press forming was investigated. The establishment of technology for controlling the wall thickness of pipe without buckling the pipe is an important technology for weight reduction of products. Using the finite element analysis method it was predicted that it is possible to increase the wall thickness of aluminum pipe with 2mm wall thickness by approximately 20% by hollow pipe press forming. Also, it was predicted that it is possible to increase the wall thickness by approximately 30% in places by eccentric pipe wall thickness increase. Also, the effect of the metal die which has a large effect on processing a pipe from a circular cylindrical shape to a rectangular tube shape was investigated.

A growing demand for lightweight products has been brought about by the rapid development of new automobiles in order to reduce fuel consumption. One of the keys to reduced fuel consumption is to utilize high-strength, light materials like stainless-steel that are difficult to form due to their strength. This paper discusses the development of pressing technology that forms a relatively high-strength stainless-steel tube with surface screw threads. Our new press-forming process was tested to obtain accurate screw threads on stainless-steel tubes. A 3-D digitizer was used to measure the accuracy of tubes manufactured by the proposed pressing method. The proposed press-forming method decreases tube thickness more effectively than conventional roll-forming technology. The maximum decrease in material thickness produced by conventional roll forming was 40%, but the maximum decrease in material thickness produced by our press-forming process was 20%. Stress and strain were clarified by using a finite-element simulation to expand the effectiveness of the new press-forming technology.

Casting of a wire-inserted strip was tried by a downward melt drag twin roll caster. Some numbers of wires of 0.3 mm diameter were inserted. Effects of the wire-interval, matrix alloy and melt temperature on the ability of the insertion of the wire were investigated. Minimum interval of the wire, with which the insertion of the wires was able, was 1.6 mm. Insertion of the wire became easy as the roll speed becomes higher. Superheat of the melt was not important factor for the insertion of the wire.

The approach to total weight reduction has been a key issue for car manufacturers as they cope with more and more stringent requirements for fuel economy. In sheet metal forming, local increases in product-sheet thickness effectively contribute to reducing the total product weight. Products could be designed more efficiently if a designer could predict and control the thickness distribution of formed products. This paper describes a numerical simulation and evaluation of the material flow in local thickness increments of products formed by an ironing process. In order to clarify the mechanism of the local increase in sheet thickness, a 3-D numerical simulation of deep drawing and ironing was performed using finite-element simulation. The effects of various types of finite elements that primarily affect thickness changes in original materials and thickness prediction were investigated. It was found that the sheet-thickness distribution could be predicted if the original material was relatively thick and if an appropriate type of finite element is selected.

To lighten total product weights, the local increases in sheet thickness of products effectively contribute to decreasing product weights, when appropriate sheet thickness distribution in product by a designer could be performed by using an accurate prediction method by simulation. The designer only could distribute thick part where needed a large moment inertia of area from the view points of the strength of the section. In the sense of the such optical designing for the variable thickness distribution in the products, we do not need to consider that sheet thickness should be constant in a product. This paper is concerned with a forming prediction during deep drawing process. To clarify the mechanism of increase of sheet thickness, a 3-D forming simulation during deep drawing by finite element method was performed. Effects of tool shapes (contacting angles to the original materials, contacting length of punch with a material) which mainly affects the results on thickness change of original materials were investigated. The thickness distribution of drawn cups was measured in order to compare simulation results obtained by the finite element method. It has been found that controlling sheet thickness distribution was possible if an original material was relatively thick, when in choosing an appropriate manufacturing condition could be selected.

A total weight reduction approach has been key issue for car manufacturers to cope with more and more stringent requirements for fuel economy. This paper describes the twin-roll casting technology of magnesium alloys that contain relatively high weight ratios of aluminum, such as AZ91,AZ101 and AZ111. The magnesium alloy sheets were cast by a horizontal twin roll caster to manufacture relatively high-strength Mg alloys with high aluminum content. The influences of such process parameters as casting temperature and roll speed were ascertained. The microstructures of cast magnesium alloy sheets were observed to investigate the effects of roll-casting conditions on crystal growth in the cast products. It was found that Mg alloys with high aluminum content can be fabricated at a roll speed of 15 m/min with a horizontal-roll caster. The grain size of the manufactured wrought magnesium alloy sheet was about 10 μm due to rapid solidification in the proposed process.

Al-SiCp aluminum alloy has some useful advantages i.e., low thermal expansion, better thermal conductivity and wear resistant. Recently, plates of Al-SiCp with thickness less than 1mm was demanded. The Al-SiCp is hard and brittle. Therefore, only hot rolling was a useful process to make thin plate. In the present study, roll casting of Al-SiCp strip was tried by a vertical type high speed twin roll caster to evaluate energy savings. The Al-SiCp strip, with thickness about 2mm, was cast directly from the molten metal. The particles of SiC were dispersed uniformly. The as-cast Al-SiCp could be coiled. The roll cast Al-SiCp had superior ductility. For this reason, the eutectic Si in matrix aluminum alloy (Al-Si alloy) became fine and globular. Cold rolling could be operated after 1-pass of hot rolling. The 1mm-thick Al-SiCp plate could be made by one-pass of hot rolling and 3-passes of cold rolling and annealing from as-cast strip.

A roll caster for making the five layers clad strip was devised. In this process, three twin roll casters were set at the vertical tandem position. This vertical type tandem twin roll caster was assembled. Five layers clad strip can be cast directly from the molten metals by the vertical type tandem twin roll caster. First layer was cast by the first caster (upper caster). Second layers were cast by the second caster (mid caster). Third layers were cast by the third caster (lower caster). Procedure of casting to make five layers clad strip is as below. First layer was cast by first caster. This layer was drawn into second caster. When first layer went into the roll-bite of the second caster, the molten metal of second layers was poured to second caster. This three layers clad strip was drawn into third caster. When this three layers clad strip went into the roll-bite of the second caster, the melting of third layers was poured to third caster. In this study, two kinds of five layers clad strips were tried by this caster. One of 3003 aluminum alloy was used for first and second layers, and 4045 aluminum alloy was used for third layers. The other of 3003 aluminum alloy was used for first layer, and AC4C aluminum alloy was used for second layers, and 4045 aluminum alloy was used for third layers. Two kinds of five layers clad strips could be cast by this caster. The interfaces of five layers clad strips were clear and flat.

A 6061 aluminium alloy and an alloy with increased Fe content, representing recycled 6061 aluminium alloy were cast into strips at speed of 30m/min by an unequal diameter twin roll caster. The Fe content of 6061 aluminium alloy and the model of recycled 6061 aluminium alloy was 0.36 mass% and 0.59 mass%, respectively. Ripple marks, which are typical surface defect of roll cast strips, did not occur on the surface of both as-cast strips. Fe content did not influence the surface condition of the roll-cast-strip. The as-cast strip was cold rolled down to 1 mm, T4 heat treatment was conducted, and then subjected to180 degrees bending test. The result of 180 degrees bending test shows that roll cast 6061 aluminium alloy and 6061 aluminium alloy with increased Fe as recycled had bending ability as same as that of roll-cast 6022 aluminium alloy. In the strip cast by the twin roll caster of the present study, increased Fe content did not influence on the result of the180 degrees bending test.

In this study, the roll casting of Al-40%Sn-1%Cu alloy was tried by an unequal diameter twin roll caster. The unequal diameter twin roll caster could continuously cast the strip. The casting load of the roll was small to prevent the flow out of the Sn. The roll-load was 0.1kN/mm(unit width). The roll casting of 400mm-width strip of 8mm-thick was tried, and it was attained. The gravity segregation of Sn did not occur. The as-cast strip could be cold rolled down to 1mm. However, this strip had much porosity. The rapid solidification was useful to prevent the porosity. The copper roll was better than steel roll to increase cooling ability. The copper roll was suitable to prevent the porosity. The temperature of solidified metal was important factor which influenced the porosity. The 4mm-thickness strip with little porosity was could be cast at the speed of 30m/min.

A single roll caster equipped with a scraper (SRCES) was devised in order to improve the free solidified surface. The scraper contacted to the free solidified surface at the constant force. The some amount of semisolid layer on the solid layer was removed and the surface became flat. The scraper was made from the mild steel plate. The mild steel plate was covered by the insulator paper to prevent the cooling of the melt. The melt pool was made on the roll by the side dam plates, back dam plate and the scraper. Therefore, a tip or a nozzle was not needed. In this study, AA6022 and AA5182 aluminum alloy were cast by SRCES. The scraped surface condition of the strip cast by SRCES was investigated. The free solidified surface was flat. The as-cast strip could be cold rolling. The free solidified surface could be cold-rolled and the roughness was reduced. The mechanical properties of cast strip were investigated by the 180 degrees bending test. There was no difference between the roll contact surface and the free solidified surface after cold rolling. This result showed that the free solidified surface could be improved up to the roll contact surface by the scraper and cold rolling. Furthermore, in this study, the scraper was applied to a twin roll caster. The aluminum alloy clad strip was cast by twin roll caster equipped with a scraper. Interface of the clad strip was connected and clear.

Roll casting of Al-SiCp composite alloy strip was tried using a vertical type high speed twin roll caster equipped with mild steel rolls. The Al-20vol% SiCp and Al-30vol%SiCp alloy could be roll-cast to the strip. The casting speed was 30m/min. The thickness of as-cast strip was thinner than 2.5mm. The SiCp powder was dispersed uniformly at the thickness direction. The as-cast strip could be thin down to 1mm by the hot rolling and the cold rolling without broken.

Manufacturing process using servo press machines have been highlighted in car manufacturers and other industries in Japan. It is necessary to establish an appropriate press working conditions for manufacturing highly accurate products with great extra value. Our aim is to investigate into effects of variable BHF (blank holding force) on press formability, comparing to using a conventional press machine. In this study, FEM analyses of deep drawing process using a variable BHF system has been conducted to demonstrate the effectiveness of a servo die cushion on formability. According to experimental results obtained with a servo die cushion, it is found that maximum load subjected to dies was reduced by 11.8 %, when using a servo press with a servo die cushion comparing to a conventional press.

A scraper was equipped to a single roll caster to improve the free solidified surface. The scraper contacted to the free solidified surface at the constant force. The some mount of semisolid layer at the surface was removed and the surface became flat. The scraper was made from the mild steel plate. The mild steel plate was covered by the insulator paper to prevent the cooling of the melt by the plate. The melt pool was made on the roll by the side dam plates, back dam plate and the scraper. Therefore, a tip or a nozzle was not needed. The AA5182 and AA6022 aluminum alloy were cast. The as-cast strips could be cold rolled. The microstructure of as-cast strip was not uniform at thickness direction. However, the microstructure became uniform after the cold rolling and the annealing.

Micro-forming using the melt-spun foil was tried by the cold rolling. A nozzle pressing melt spinning method was adopted to cast the Al-14mass%Si foil. Al-14mass%Si was near to the eutectic, and the grain is very small. The thickness of the as-cast strip was 0.2mm. The nozzle pressing melt spinning method can cast the foil which thickness is thicker than 0.1mn with the sound surface. The average cooling rate of the melt-spun foil was about 105 °C/s. The cooling rate of the roll contact surface of the foil was higher than 105 °C/s. The as-cast foil was cold-rolled using a Cr-plated roll down to 0.1mm. The cold-rolled foil was recovered and polished. The micro-forming was operated by the cold-rolling using the roll with micro-die of V-groove. The rolling speed was 1m/min. The grooves were machined on the tip, and this tip was attached to the roll. The angle of the V-groove was 60 degrees, and depth was 1, 3, 5 and 10μm. The projection was formed by the cold rolling on the roll-contact surface of the foil. The height of the projections was about 0.1μm lower than the depth of the each groove.

The net-inserted metal matrix composite strip could be cast by a twin roll caster at only one process. The caster for composite strip was assembled by combination of the open-top melt drag type and the downward melt drag type caster. The matrix was Al-12mass%Si, and inserted net was made from SUS304 stainless steel. The diameter of the wire of the net was 0.29 mm, and distance between the wires was 0.98 mm (#20). The roll speed was 30 m/min. The net was not reacted with the matrix, and there was not gap between the matrix and the net. The mechanical property of the net-inserted composite strip was affected by the direction of the wire of the net. When the angle of the wire against the tensile direction was 45 degrees, elongation of the composite became better than that of the matrix from 14% up to 23%. This reason was improvement of the local contraction of the composite strip. The net-inserted composite strip could be cold rolled. The reduction of the net was smaller than that of the strip. The reduction of the wire at rolling direction was larger than that of the wire at lateral direction.

The growing demand for lightweight products has been increased by the rapid development of automobiles in order to reduce fuel consumption. One of the keys to reduced fuel consumption is to utilize high-strength, light materials like stainless steel that are difficult to form due to their high strength. This paper discusses the development of pressing technology that forms relatively high-strength stainless-steel pipe with surface screw threads. Our new press-forming process was tested to obtain accurate screw threads on stainless-steel pipe. A 3-D digitizer was used to measure the accuracy of pipes manufactured by the proposed pressing method. Our proposed press-forming method decreases pipe thickness more effectively than conventional roll-forming technology. The maximum decrease in material thickness produced by conventional roll forming was 40%. The maximum decrease in material thickness produced by our press-forming process was 20%.

Local increases in product sheet thickness effectively contribute to reducing total product weight. Products could be designed efficiently if a designer could predict and control the thickness distribution of formed products. This paper presents a numerical simulation and evaluation of the local thickness increment of products formed during the ironing process. To clarify the mechanism of the local increase of sheet thickness, a 3-D numerical simulation during ironing was performed by the Finite-Element Method. Tool shapes (contact angles with the original materials and contact length of the punch with the material) that primarily affect thickness changes of original materials were evaluated. It was found that the sheet thickness distribution could be controlled if the original material were relatively thick, when appropriate manufacturing conditions could be selected.

Roll casting of Al-25mass%Si hyper eutectic aluminum alloy strip was tried by an unequal diameter twin roll caster. The casting speed was 10m/min. The thickness of the strip was about 2mm. The eutectic Si and primary crystallized Si were very fine by the effect of the rapid solidification. The size of the primary crystallized Si was not uniform at the thickness direction. The primary crystallized Si at the near surface was finer than that of inside. The eutectic Si was finer than 2μm. The strip could be cold rolled after hot rolling and annealing.