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A twin-wheel caster with a hole nozzle was developed to cast thin aluminum alloy wire. The lower large wheel had a trapezoid groove with a cross-sectional area of 22.5 mm2, and the upper small wheel was flat. Molten-metal flow onto the wheel was controlled by the gap between the wheel and the nozzle, and the ejection angle of the molten metal. When the gap was not appropriate, bulges formed on the free solidified surface of the molten metal on the wheel. The bulges were flattened by setting the gap to the correct size of 3 to 4 mm. The appropriate angle was found to be 60°. A thin wire of 6061 aluminum alloy could be cast continuously at a speed of 5 m/min. The cross-sectional area of the nozzle hole was 3 mm2. The cross-sectional area of the as-cast wire was 42.7 mm2.

Fe was added to Al-4.7%Mg to make model alloys of recycled Al-Mg alloy. The effect of Fe addition on the mechanical properties of the Al-4.7%Mg strip cast using a single-roll caster equipped with a scraper was investigated. The added Fe content was 0.2, 0.4, 0.6, and 0.8%. The as-cast strip cast at 30 m/min was cold rolled down to a thickness of 1 mm thick annealed to conduct a tensile test and a cup test. The as-cast strip could be cold rolled without cracking. The tensile stress and the 0.2% proof stress were only slightly affected by the addition of Fe. The elongation gradually decreased as the Fe content increased. When the Fe content was 0.8%, the elongation in the casting direction was 27.7%. The limiting drawing ratio did not deteriorate until the Fe content was 0.4%. When the Fe content was 0.4% and 0.8%, the limiting drawing ratios were 2.0 and 1.7, respectively.

solidification, process shortening and energy saving. A twin-wheel caster equipped with two additional horizontal wheels was proposed to cast thin aluminum alloy wire at higher speed. In the proposed twin-wheel caster, a groove was machined on the lower wheel. Two small horizontal wheels were positioned between the molten-metal-pouring launder and the upper wheel to assist the solidification of poured molten metal and to prevent burr formation. The alignment of the horizontal wheel sensitively affected the occurrence of wire defects. An Al-1.2%Fe wire with a cross section of 6.2 mm2 was cast at 15 m/min. Thinner wires without burring could be cast at a speed higher than that of the twin-wheel caster without the horizontal wheels. The surface condition of the as-cast wire cast by the twin-wheel caster equipped with horizontal wheels was worse than that of the casting using the twin-wheel caster without horizontal wheels.

The temperature of a strip cast using a vertical type high-speed twin-roll caster was measured by inserting a k-type thermocouple into the strip. The effects of the roll speed and roll load on the cooling rate and temperature at the roll gap were investigated using two aluminum alloys: A383 and Al–4.8%Mg. The thickness of the thermocouple was 0.1 mm, and the sampling time was 0.01 s. The cooling rate increased and the temperature at the roll bite decreased with decreasing roll speed and increasing roll load. The positions of the liquidus and solidus lines were measured, and the reduction of the thickness of the strip was inferred from the roll gap at the solidus line.

Al-Mg alloys with 3, 4.7, 6, 8, and 10%Mg were fabricated using gravity casting with a copper mold at a cooling rate of 30.6 °C/s. Hot forging was conducted at 500 °C with 50% reduction. An increase in Mg content increased the tensile stress but decreased the elongation in the as-cast ingot. The tensile stress and especially the elongation were increased by hot forging. The tensile stress, 0.2% proof stress, and elongation for hot-forged Al-8%Mg were 337 MPa, 154 MPa, and 24%, respectively. These mechanical properties were obtained without heat treatment. The results show that Al-Mg is suitable for cast forging in terms of mechanical properties and energy consumption.

Effect of casting conditions on ripple mark and surface crack of as-cast Al-4.7%Mg strip was investigated. A vertical type high speed twin roll caster was used. A casting speed was 30 m/min. Casting conditions were tip-shape of a back-dam plate, gap between a roll and the back dam plate and texture on the roll-surface. The texture on the roll-surface was useful to reduce the ripple mark. In bending test conducted to investigate surface crack of as-cast strip, the texture on the roll surface was effective to the reduce the crack. The position of the crack was not coin side with the position of the ripple mark. This result shows that there is no correlation between the ripple mark and the ductility or the strength of as-cast strip. Small roll load was effective to reduce the crack and degree of the ripple mark. Effect of the roll load on the ripple mark was discussed including solidification delay and seepage of Magnesium.

Fe (0.2, 0.4, 0.6, and 0.8 %) was added to roll-cast Al-4.8%Mg alloy to create a model of recycled Al-4.8%Mg and its effect was investigated. An unequal-diameter twin-roll caster was used. The roll speed was 20 m/min. An as-cast strip was cold-rolled down to 1 mm and annealed. Its mechanical properties were then evaluated. The surface condition of the as-cast strip was not influenced by the Fe content. The thickness of the as-cast strip decreased with increasing Fe content. The tensile strength and 0.2% proof stress increased with Fe content up to 0.4%Fe and then decreased. When 0.8% Fe was added to Al-4.8%Mg, the tensile strength and 0.2% proof stress became higher than those for Al-Mg. Elongation and the limiting drawing ratio gradually decreased with increasing Fe content. When 0.8% Fe was added, elongation in the lateral direction was 19.6% and the limiting drawing ratio was 1.7.

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.

A scraper was attached to an unequal-diameter twin-roll caster without requiring large modifications. This caster was used as a 1000 mm diameter single roll caster equipped with a scraper, and its strip casting ability was tested. The effects of the scraper angle and load, the roll speed, and the pouring temperature of the molten metal on the scribed surface, thickness distribution and average strip thickness were investigated. The scribed surface characteristics were sound and the thickness distribution was flat when the scraper angle was 60° and the scraper load was in the range of 1 to 4 kg. When the scraper load was more than 1 kg, the thickness distribution was uneven. The average strip thickness decreased as the roll speed increased. The pouring temperature of the molten metal influenced the evenness of the solidified layer thickness. The solidified layer became even as the molten metal temperature was decreased. A strip cast with the determined optimal conditions was then cold rolled down to 1 mm to improve its surface quality.

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 introduces the direct cladding of magnesium and aluminum alloys using a horizontal twin roll caster in one step. A horizontal twin roll caster can cast a Mg/Al clad strip with thickness exceeding 5mm at a roll speed of 8m/min in one step, which is difficult for a vertical twin roll caster. Therefore, it is possible to cast a thick clad strip with different melting point alloys using a horizontal twin roll caster at low speed. It is also possible to cast clad strips using as the overlay an alloy that has a higher melting point than that of the base strips. The thickness of the Mg/Al clad strip is 6.5mm, and the ratio of the Mg layer to the Al layer is 3:2. The surface of the clad strip is good, and there is no void between bonding interfaces. The mixing layer of the bonding interface is deeply related to the reduction rate. As the reduction rate increases, the mixing layer becomes more balanced and the thickness of the mixed layer decreases to 68μm. By observation of the interface of the cladded material, the mixed layer of the bonding interface is divided into two layers. It has been found the mixed layer near the Al layer has the highest hardness (up to 228HV), and the tensile shearing strength of the manufactured Mg/Al clad strip was 44MPa.

Improvement of fuel efficiency and reduction of carbon dioxide emission are important issues in the automotive and aviation industries. To achieve these issues, materials that are lightweight and have excellent heat resistance are required. For this reason, various alloys have been proposed. Among them, TiAl intermetallic compounds have excellent low specific gravity and high strength at high temperature. However, TiAl is difficult for machining and easily oxidized, so casting is difficult. For this reason, a method using reaction sintering has been studied, though it is difficult to obtain low oxygen concentration TiAl alloy powder. Therefore, the process to produce TiAl parts from Ti powder and Al powder is studied. However, in this method, when a mixed powder of Ti and Al is sintered, a phenomenon called ignition with a rapid temperature increasing may occurs, and ignited parts are swelling and becomes high porosity.

In recent years, metal injection molding (MIM) has been adopted as a process for manufacturing a solenoid valve which is a component of an electronic fuel injector, and PB permalloy components have been commercialized. However, Ni, an element of PB permalloy, is expensive material, making it difficult to produce the fuel injector component at a low cost. As a solution to this problem, we studied the magnetic and mechanical properties of Fe-Cr-Si alloys by MIM process. These results revealed that the magnetic and mechanical properties were improved by reducing Cr content. However, reducing Cr content is expected to reduce corrosion resistance of the alloys. In this study, Fe-Cr-Si-Mo alloy specimens containing Mo to improve corrosion resistance are manufactured by MIM process, and we investigated the magnetic and mechanical properties. These results revealed that Fe-10Cr-3Si-2Mo alloy is a material with an excellent balance between magnetic and mechanical properties.

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.

A simple twin-wheel caster is proposed for casting thin bare wire. An unequal diameter twin wheel caster equipped with rotating side-dam plates is proposed for casting a thin bare wire of aluminum alloy to shorten the fabrication process. The rotating side-dam plate was made of mild steel. Al-10%Mg bare wire with a rectangular cross section could be cast at wheel speeds of 3 and 4 m/min. Area of the bare wire was less than 100 mm2 at these wheel speeds. The side surface of the bare wire was made flat by the rotating side-dam plates. The rotating side-dam plates prevent the cross section of the bare wire from becoming concave.

In recent years, metal injection molding (MIM) has been adopted as a process of manufacturing a solenoid valve which is a component of an electronic fuel injector, and PB permalloy component has been commercialized. However, Ni that is an element of PB permalloy is expensive material, and it makes difficult to produce the injector component in low cost. To reduce the production cost, we can use Fe-Cr alloys, although there are few studies on Fe-Cr alloys by MIM process. In this study, Fe-Cr-Si alloy specimens were manufactured by MIM process and the magnetic and mechanical properties were investigated. From these results, we found that high performance Fe-Cr-Si alloy can be obtained by setting Si content to 3% and reducing Cr content.

In this paper, twin roll casting of magnesium alloys with high aluminum content such as, Mg-11 mass%Al-0.2 mass%Mn, Mg-12 mass%Al-0.2 mass%Mn, Mg-13 mass%Al-0.2 mass% have been performed for the purpose of use as an original material for hot forging. Also the mechanical properties of the cast materials were examined. A 10 miri-meters thick strip was cast by the use of a horizontal twin roll caster. The microscopic observation was conducted to investigate into the precipitation of the metal compounds such as Mg17Al12, and the Vickers hardness of the cast strips test were performed. From the result of the roll casting experiments, a 10 mm thick strip was continuously cast at a roll speed of 3.1 m/min. The average grain size of the casting strips was about 46 micron meters. When the aluminum content was 13%, the hardness of the twin roll cast (TRC) strips became 1.7 times higher than that of extruded AZ 31. Also, a uniaxial compression test at elevated temperature was conducted to obtain a true strain-true stress curve for examining possibility of direct hot forging (DHF) of TRC magnesium alloys with high aluminum content.

The factors affecting the shape and size of burrs that form at the edges of strips cast by a vertical type twin roll caster were investigated in this study. The size of the burr was found to be affected by the Si content of the strip. When the Si content was larger than 7 mass%, the burrs became larger. The position of the lower edge of the side dam plate also affected the shape of the burr. The burrs that formed were generally perpendicular to the strip surface but changed to being parallel to the strip surface as the position of the lower edge of the side dam plate was displaced upward from the center of the rolls.

In recent years, the movement that banning the sale of gasoline cars and diesel vehiclesespecially in Europe and allowing only electric cars for passenger’s cars has been accelerated. Forexamples, Germany’s federal council, the Bundesrat, has passed a resolution calling for a ban oncombustion engine cars by 2030. If the ban were to go through, German citizens would only bepermitted to purchase electric or hydrogen-fueled cars. In Norway, until 2025 there is a movement tolegislation prohibiting the registration of new cars for passenger car gasoline and diesel cars.Beginning in 2025 in the Netherlands, a bill to prohibit the sale of new cars for gasoline and dieselvehicles was submitted to Congress. Under the circumstances, the growing demand for light weightproducts for automotive industries has been increased due to global trend of environmentalpreservation. Although requires of magnesium has risen dramatically, production of magnesium alloysheet remains still at a very low level in practical use. The aim of the study is to establish a guidelinefor roll design in the roll forming of wrought magnesium alloys to extend practical use of roll formedproducts of wrought magnesium alloys. A three-dimensional elasto-plastic analysis by finite elementmethod has been conducted to express exact roll forming behavior of wrought magnesium alloys thathave different stress-strain curves in tension and compression. A simple V-sections were formed by atandem six stands roll forming machine to demonstrate effectiveness of the simulation methods withdifferent stress-strain curves in the case of tension and compression. Also, spring back analysis hasbeen performed to investigate exact cold roll forming phenomenon for wrought magnesium alloysheets.

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.

This paper deals with characteristics of hot forging of twin roll cast magnesium alloyswhich have relatively high aluminum content. High tensile strength magnesium alloys containing 9 to12% aluminum, such as Mg-9%Al-1%Zn, Mg-10%Al-1%Zn, Mg-11%Al-1%Zn, andMg-12%Al-1%Zn have been made by twin roll casting. A new experiment was performed for hotforging of high strength magnesium alloys with high aluminum content was performed. From theresults, using magnesium alloys with high aluminum content yielded less compressive deformationresistance than AXM403. It was also demonstrated that hot forging of magnesium alloys with highaluminum content produces small magnesium crystals (about six micro meters) and crystallizedsubstances. The mean grain size of the microstructure of Mg-12%Al-1%Zn forged at 623K was lessten micrometers although that of the Mg-9%Al-1%Zn was about thirty micrometers. The small betaphase which precipitates in the twin roll cast Mg-12%Al-1%Zn was distributed uniformly comparingto Mg-9%Al-1%Zn. From the result of microscopic observation of the forged products, it has beenrecognised that the Hall-petch rule between mean grain size of forged materials and Vickers hardnesshas been proved. The effects of the dynamic recrystallization on the microstructures of the twin-rollcast products seem to be different in terms of aluminum content. Due to rapid cooling of twin-rollcasting process process, the fabricated magnesium material could be used for hot forging. By applyinga servo press machine, a hot-forging experiment was performed with development of high strengthmagnesium alloys. A novel material that show higher hardness have been fabricated by usingtwin-roll casting process. It has also been clarified that the aluminum content affect precipitation ofbeta phase as well as grain size.

Strip casting of Al-40%Sn-1%Cu, which is an aluminum alloy used for sliding bearings, was attempted using an unequal diameter twin roll caster. The conditions required to cast sound strips, including the roll speed, molten temperature, roll load, solidification length, melt head, and use of an upper plate, were investigated. The roll load required to make a stable strip surface was 0.01 kN/mm, and the porosity was minimum when the solidification time was less than 0.6 s. The solidification time was controlled by the roll speed and the solidification length. The casting temperature must be set below 670°C to properly solidify the molten metal, and the metal microstructure became finer as the melt head decreased.

Among the problems encountered when roll casting Al-405Sn-1%Cu, which is an aluminum alloy used for sliding plate bearings in large maritime diesel engines, are solidified chips embedded in the strip and scratch marks on the lower roll contact surface. In this study, three different improvement methods aimed at eliminating these particular defects—vibrating the side plates and back dam plate, adding a vibrating plate, and varying the casting conditions—are examined. Vibrating the side plates and dam plate was found to be effective for preventing these defects, while adding another vibrating plate was comparatively less effective. As for casting conditions, it was also determined that the occurrence of these defects could be reduced by increasing the roll speed, and that the molten metal casting temperature had little or no influence on defect formation.

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 deals with friction properties and deformation resistance during hot forming of Mg-Al-Ca-Mn series magnesium alloys. Friction coefficients between dies and magnesium alloys were obtained by ring compression tests that used graphite, PTFE, and an oil lubricant in a hot-forging process. Hot forging was performed under various conditions to clarify the effects of types of lubricants and slide motion of the press machines on friction properties. Two types of slide motion, a constant velocity motion and a pulse motion were selected in the ring-compression test. It was found that graphite with an oil lubricant effectively eliminated die sticking in hot forming of magnesium alloys. The isothermal deformation resistances were derived using friction coefficients obtained by ring-compression tests as well as finite-element simulations. The predicted stress strain curves with temperature were examined with the stress-strain relationship obtained in experiments using a servo press and demonstrated the effectiveness of the proposed method.

A sound three-layer clad strip of 4045, 3003, and 4045 was cast by a vertical type tandem twin roll caster. However, a sound three-layer clad strip of 5182, 3003, and 5182 could not be cast. The 5182 overlay strip did not bond to the 3003 base strip. The latent heat of Si and Mg are 1787 kJ/kg and 230 kJ/kg, respectively. The latent heat affected the rise in temperature of the base strip. The 3003 was not heated up to a temperature suitable for bonding with the 5182 overlay strip. A sound two-layer clad strip of 3003 and 5182 could be cast by a twin roll caster equipped with a scraper. The temperature of the 3003 was near the solidus line, and sound bonding occurred.

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.

In manufacturing car components, the hollow parts manufacturing method is useful for reducing the product weight, especially in drivetrain parts such as long shafts. Long, hollow shafts should have middle portions with large diameters and thin walls and end portions with small diameters and thick walls in order to reduce weight while maintaining pipe strength.Generally, such long shaft parts are manufactured by reducing the end portion of the pipes with the equivalent diameter and desired hollow part thickness for the middle portion of the parts. It is difficult for manufacturers to successfully thicken the pipe wall locally by press forming because pipes buckle easily during the process. Using thick pipe is one way to prevent buckling, but when using thick pipes, we could not reduce weight much. Automotive industries have desired a manufacturing process that can reduce pipes (relatively thin pipes) without buckling.This paper clarifies the relationships among the forming conditions and the thickening ratio (thickness after forming / thickness before forming) in uniaxial press forming by experiments and finite-element simulation. Steel pipes with 39.0mm outer diameter and 7.6mm thickness were used in the experiment. The relationship between the thickening ratio and the forming load that depends on the die shape, lubrication, and slide motion of the press machine was investigated. An appropriate manufacturing condition that could reduce pipes without buckling was obtained. We clarified that the pipe wall thickness could be increased ten percent. The details of material flows in reducing pipes without buckling were discussed using finite-element simulation.

This paper reports on hot forging of high aluminum content magnesium alloy sheets manufactured using horizontal twin-roll casting. AZ111 and AZ131 were applied for twin-roll casting, and a hot-forging test was performed to manufacture high-strength magnesium alloy components economically. For twin-roll casting, the casting conditions of a thick sheet for hot forging were investigated. It was found that twin-roll casting of a 10mm-thick magnesium alloy sheet was possible at a roll speed of 2.5m/min. The grain size of the cast strip was 50 to 70µm. In the hot-forging test, blank material was obtained from as-cast strip. A servo press machine with a servo die cushion was used to investigate appropriate forging conditions (e.g., temperature, forging load, and back pressure) for twin-roll casts (TRCs) AZ111 and AZ131. It was determined that high aluminum content magnesium alloy sheets manufactured using twin-roll casting could be forged with a forging load of 150t and a back pressure of 3t at 420 to 430°C. Applying back pressure during hot forging effectively forged a pin-shaped product.This paper reports on hot forging of high aluminum content magnesium alloy sheets manufactured using horizontal twin-roll casting. AZ111 and AZ131 were applied for twin-roll casting, and a hot-forging test was performed to manufacture high-strength magnesium alloy components economically. For twin-roll casting, the casting conditions of a thick sheet for hot forging were investigated. It was found that twin-roll casting of a 10mm-thick magnesium alloy sheet was possible at a roll speed of 2.5m/min. The grain size of the cast strip was 50 to 70µm. In the hot-forging test, blank material was obtained from as-cast strip. A servo press machine with a servo die cushion was used to investigate appropriate forging conditions (e.g., temperature, forging load, and back pressure) for twin-roll casts (TRCs) AZ111 and AZ131. It was determined that high aluminum content magnesium alloy sheets manufactured using twin-roll casting could be forged with a forging load of 150t and a back pressure of 3t at 420 to 430°C. App...

Relationships among the forming conditions (such as shapes of dies, lubrication conditions, and slide motion of the press machine) and the thickening ratio (thickness after forming / thickness before forming) has been clarified in uniaxial press forming by experiments and a three dimensional finite element simulation. Steel pipes with 39.0mm and 7.6mm thickness were used in the experiment. The relationship between thickening ratio and the forming load that depends on the die shape, lubrication, and slide motion of the press machine was investigated. It has also been found that an eight percent increase of the wall thickness of the pipes could be possible without buckling. It has been clarified that thickening ratio during die forming could be predictable by using a finite element simulation.

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.