Papers by Keyword: Strip Casting

Abstract: 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.

Abstract: Casting of a wire inserted strip was investigated using a downward melt drag twin roll caster. A nozzle was mounted to each roll. The wire was inserted between the lower and upper strip. Effect of use of two nozzles on the insertion of the wire was investigated. The insertion of the wire by the two nozzles was easier than one nozzle. The surfaces of the wire inserted strip cast using two nozzles was more sound than that cast using one nozzle. The position of the wire at thickness direction was almost center. When different aluminum alloys were poured from an upper nozzle and from a lower nozzle, a wire inserted clad strip could be cast.

Abstract: Effect of Si content of Al-Si matrix on roll cast wire inserted strip was investigated in this paper. 99.5%Al, Al-4%Si , Al-12%Si and Al-18%Si were used as matrix. Slit depth of the nozzle, superheat of melt, wire-diameter and roll speed was chosen as the casting parameters, too. Addition of the Si was useful to prevent the reaction between the matrix and the wire. A downward melt drag twin roll caster could cast the wire inserted strip of the Al-Si matrix of which Si content was ranging up to18%. Composite strip, which matrix was hyper eutectic Al-18%Si, could be cast at the speeds up to 20m/min. The gap between the wire and matrix became thin when the superheat was high. When the slit depth of the nozzle was too shallow, the wire could not be inserted in the strip. The thickness of the wire inserted strip became thinner as the roll speed became higher.

Abstract: 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.

Abstract: A vertical tandem positioned twin roll caster and an unequal diameter twin roll caster were used in this study. Factors which affected the connecting of the strips in the fabrication using a roll caster were investigated. They were influences of oxide film, roll-load (separating force) and temperature of a strip. In the clad-strip casting by the roll caster, the connecting could be operated before the oxide film became firmly. Mn was useful element to prevent the oxidation. The roll-load could break the oxide film existed on the strip surface. Prevention of the occurrence of the oxide film was important to make strip connecting condition firm. In the casting of the clad strip using an unequal diameter twin roll caster, strips did not contact to the atomosphere before connecting.

Abstract: 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.

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: The net-inserted metal matrix composite strip could be cast by a twin roll caster at only one process. The net could be inserted in the strip or lower surface of the aluminium alloy strip. The matrix was Al-12mass%Si, and inserted net was made from SUS304 stainless steel. The diameter of the wire of the net was 0.29mm, and distance between the wires was 0.98mm (#20). The roll speed was 30m/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.

Abstract: The simulation studies were carried out on the oriented silicon steel produced by thin slab casting and rolling (TSCR) and twin-roll strip casting in the laboratory. The precipitation of inhibiter, formation of microstructure and texture were investigated before cold rolling. The inhomogeneous microstructure and texture gradient were observed in the 7-pass hot-rolled strip（2mm）for TSCR process, and texture gradient was not changed after normalizing, and the twin-roll strip casting directly supplied a strip with approx 2mm of thickness being same as that of hot-rolled strip by TSCR. The microstructure of twin-rolling casting strip was almost composed of all equiaxed grains which similar to the normalizing microstructure in TSCR process, but the random texture was obtained by twin-rolling strip casting. The dispersed and clustered precipitates were presented in hot-rolled strip when the ingots were soaked at 1200°C and 1150°C respectively for the TSCR process. And disperse and acicular precipitates were observed by TEM for air-cooling cast strips for process twin-rolling casting.

Abstract: Strip casting process is a kind of promising near net shape technology for producing magnesium alloys strip. The microstructure and mechanical properties of CO2 laser welded as-cast AZ31 magnesium alloy sheet were investigated. The microstructure of base material (BS) was typical columnar dendritic structure. A significant grain refinement occurred in the fusion zone (FZ) due to the rapid cooling, while an obvious grain coarsening occurred in the heat affected zone (HAZ). The tensile strength and elongation at fracture of weld joints were reduced due to the weld depression caused by high heat input. The hardness in the FZ was the highest due to fine grains, while there was a decrease in hardness of the HAZ, but little variation compared with the hardness of the BS.