Continuous extruding/ extending formiug process for A2017 alloy in semi-solid state was proposed through installing extending die at the outlet of shearing- cooling- rolling （SCR） machine. A series of experiments to...Continuous extruding/ extending formiug process for A2017 alloy in semi-solid state was proposed through installing extending die at the outlet of shearing- cooling- rolling （SCR） machine. A series of experiments to produce fiat bar of A2017 alloy were carried oat. The forming process, metal flow behavior in die and microstructure and mechanical property of prodacts were investigated. It is shown that if the pouring temperature of melt was higher, the die was filled with semi-solid slurry with low solid fraction and periodical cracks would occur on the product surface ; If its pouring temperature was lower or the preheating temperature of die was lower, semisolid slurry would solidify rapidly and block the die after entering the cavity. The analysis of mass flow trace shows that the semi-solid slurry move forward layer by layer and fills the die extending cavity in radiation manner and the velocity of mass flow in the central area of extending cavity and exit of mould is the maximum, and then decreases gradually from the center to both sides of die wall. By inereasiug the die extending angle, the velocity of mass flow becomes more homogeneous. Under rational process control and die design, the A2017 fiat bar with transverse section of 10 × 50 mm and with good surface and fine equiaxed grains can be obtained by continuous extruding/extending forming process. The product＇s tensile strength and elongation are 420.5 MPa and 14.2% , respectively.展开更多
A self-made single-roll stirring (SRS) machine was used to manufacturesemisolid A2017 alloy, the mechanism of A2017 alloy formation was investigated. It was shown thatA2017 dendrites growing on the rough roll surface ...A self-made single-roll stirring (SRS) machine was used to manufacturesemisolid A2017 alloy, the mechanism of A2017 alloy formation was investigated. It was shown thatA2017 dendrites growing on the rough roll surface are crashed into fragments by the roll, which moveand grow freely then contribute the formation of finer spherical microstruc-ture. When casting at710-750℃, fine and homogeneous spherical or elliptical grains of A2017 alloy were obtained.Extending forming mould has been designed and was installed at the exit of roll-shoe gap. A2017alloy was formed by extending continuously at the semisolid state on SRS machine. Throughcontrolling pouring temperature, semisolid forming and extending extrusion was combined organically.A2017 product with fine surface and rectangular transection of 14 mm x 25 mm was obtained. Bycontrast to the national standard, the fracture strength and elongation of A2017 products producedfrom extending semisolid extrusion have been improved with an increase of 100 MPa and 29%,respectively.展开更多
This paper presents an experimental research on extrude-bulge forming of tee tubes with plastic medium,an universal device especially designed for this forming process and some parameters having effects on the forming...This paper presents an experimental research on extrude-bulge forming of tee tubes with plastic medium,an universal device especially designed for this forming process and some parameters having effects on the forming process.Comparison of results of the theoretical analysis with experimental results shows a very good agreement between them.展开更多
基金Funded by the National Natural Science Foundation of China(No.50274020) and Baoshan Iron &Steel Corporation of Shanghai
文摘Continuous extruding/ extending formiug process for A2017 alloy in semi-solid state was proposed through installing extending die at the outlet of shearing- cooling- rolling （SCR） machine. A series of experiments to produce fiat bar of A2017 alloy were carried oat. The forming process, metal flow behavior in die and microstructure and mechanical property of prodacts were investigated. It is shown that if the pouring temperature of melt was higher, the die was filled with semi-solid slurry with low solid fraction and periodical cracks would occur on the product surface ; If its pouring temperature was lower or the preheating temperature of die was lower, semisolid slurry would solidify rapidly and block the die after entering the cavity. The analysis of mass flow trace shows that the semi-solid slurry move forward layer by layer and fills the die extending cavity in radiation manner and the velocity of mass flow in the central area of extending cavity and exit of mould is the maximum, and then decreases gradually from the center to both sides of die wall. By inereasiug the die extending angle, the velocity of mass flow becomes more homogeneous. Under rational process control and die design, the A2017 fiat bar with transverse section of 10 × 50 mm and with good surface and fine equiaxed grains can be obtained by continuous extruding/extending forming process. The product＇s tensile strength and elongation are 420.5 MPa and 14.2% , respectively.
基金This project is financially supported by State Key Fundamental Research of "973" Development Plan (No. G2000067208-4)
文摘A self-made single-roll stirring (SRS) machine was used to manufacturesemisolid A2017 alloy, the mechanism of A2017 alloy formation was investigated. It was shown thatA2017 dendrites growing on the rough roll surface are crashed into fragments by the roll, which moveand grow freely then contribute the formation of finer spherical microstruc-ture. When casting at710-750℃, fine and homogeneous spherical or elliptical grains of A2017 alloy were obtained.Extending forming mould has been designed and was installed at the exit of roll-shoe gap. A2017alloy was formed by extending continuously at the semisolid state on SRS machine. Throughcontrolling pouring temperature, semisolid forming and extending extrusion was combined organically.A2017 product with fine surface and rectangular transection of 14 mm x 25 mm was obtained. Bycontrast to the national standard, the fracture strength and elongation of A2017 products producedfrom extending semisolid extrusion have been improved with an increase of 100 MPa and 29%,respectively.
文摘This paper presents an experimental research on extrude-bulge forming of tee tubes with plastic medium,an universal device especially designed for this forming process and some parameters having effects on the forming process.Comparison of results of the theoretical analysis with experimental results shows a very good agreement between them.
