Papers by Keyword: Roll-Casting

Abstract: 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.

Abstract: With composite energy-field of ultrasonic field and electromagnetic field introduced into the roll-casting process，AZ31B magnesium alloy has been acquired successfully，during this process，the effect of composite field on structure and properties of AZ31B magnesium roll-casting alloy are studied. The result shows that the composite field can decrease the grain size greatly from 60-80μm to 12-18μm compared with the conventional roll-casting(without out-field), improving the tensile strength and yield strength by 13% and 35% respectively and the elongation increased by 82.2%（average value）.Meanwhile，the microstructure of magnesium alloy obtained with the composite field are more uniform after annealing，mechanical properties are improved greatly as well.

Abstract: The roll-casting technology of 5000 series aluminum alloy is one of the difficulties at present. Roll-casting technology was employed in this paper and high quality 5005 aluminum alloy sheets were fabricated successfully under different conditions. The solidification of melt in roll-casting process is the rapid directional solidification. The effect of magnetostatic field on microstructure of 5005 aluminum alloy sheet by roll-casting has been investigated and analyzed. The results indicate that imposing magnetostatic field can refine the grains of 5005 aluminum alloy.

Abstract: Porosity occurred in the 5182 aluminum alloy strip cast by a vertical type high speed twin roll caster. The porosity was caused by high-roll-speed and low-roll-load. Improvement of the porosity was tried by a scraper. The scraper was mounted on the roll, and the scraper was moveable depend on the thickness of the solidified layer on the roll. The scraper scribed the semisolid layer to improve the porosity. The scraper was useful to decrease the porosity of roll cast 5182 aluminum alloy strip.

Abstract: The effect of electromagnetic field on microstructure of roll-casting 5052 aluminum alloy sheet has been investigated and analyzed. The results indicate that imposing static magnetic field can refine the grains of 5052 aluminum alloy during the roll-casting; accordingly, imposing static magnetic field and alternating current at the same time, the grains are remarkably refined and equiaxed due to electromagnetic oscillation effect.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Semi-solid Continuous roll-casting process applied to produce the AZ91D magnesium strips and its microstructure was studied in this paper. In order to examine further process ability and forming property of the roll-casting strips, hot and cold rolling and punching experiments were investigated. It was clarified that it is significant to combine the semi-solid process techniques with roll-casting techniques, through which we can get high quality magnesium alloy strips with nondendritic structure and improve the overall properties of the products. The largest deformation by cold rolling and hot rolling can reach 18% and 21% respectively with one-pass roller.