A heat resistant aluminum alloy pipe blank with dimensions of d 700/300 mm×1 200 mm was prepared by the multi layer spray deposition technology. Optical microscopy, X ray diffractometry and transmission electron ...A heat resistant aluminum alloy pipe blank with dimensions of d 700/300 mm×1 200 mm was prepared by the multi layer spray deposition technology. Optical microscopy, X ray diffractometry and transmission electron microscopy were used to analyze its morphologies and microstructures. The results show that the microstructures of the pipe blank are homogeneous and the precipitates are uniformly distributed d 25～70 nm spherical or sphere like Al 12 (Fe,V) 3Si particles, its mechanical properties at room temperature and 350 ℃ after densification by extrusion are σ b=412 MPa, δ =7.6% and σ b=187 MPa, δ =7.6%, respectively. The analyses indicate that the proper match of the motion rates of atomizer and substrate can produce deposited blanks with uniform thickness and relatively high cooling rate.展开更多
Suitable microstructures required for semisolid casting were formed by using a vertical pipe.Different lengths of vertical pipe,slug dimensions and pouring time were used to investigate their influence on the microstr...Suitable microstructures required for semisolid casting were formed by using a vertical pipe.Different lengths of vertical pipe,slug dimensions and pouring time were used to investigate their influence on the microstructure of A356 alloy.The results indicate that at the same length of the vertical pipe,the morphology of the primary α(Al)gradually deteriorates by the enlargement in the slug size,but the deteriorating speed slows down with increasing pipe length.They also reveal that the increase in the pipe length improves the microstructure,whereas no further improvement appears when the pipe length reaches a certain value.The optimum length of the pipe obtained in the present work is 430 mm.The microstructure of larger slug poured at higher pouring temperature gets worse and it can be improved by moderately elongating pouring time.The relative mechanisms were also discussed.展开更多
The copper-based shape memory alloy pipe joint was applied in the field of oil pipelines jointing as well as installing. It has many advantages than anything. In the paper, the basic principle and connection influence...The copper-based shape memory alloy pipe joint was applied in the field of oil pipelines jointing as well as installing. It has many advantages than anything. In the paper, the basic principle and connection influence factors of copper-based shape memory alloy pipe joint were described. Experimental results shows the copper-based shape memory alloy pipe joints can be used in oilfield oil pipeline connection and it can solve the inner pipe joint corrosion damage problem by welding.展开更多
A thermal-mechanical and micro-macro coupled finite element（FE） model for the hot extrusion process of large-scale thick-walled Inconel 625 pipe was developed based on the DEFORM-2D platform.Then,the influence rules...A thermal-mechanical and micro-macro coupled finite element（FE） model for the hot extrusion process of large-scale thick-walled Inconel 625 pipe was developed based on the DEFORM-2D platform.Then,the influence rules of the key extrusion parameters on the average grain size and grain uniformity of the extruded pipe were revealed.The results show that with the increase of initial billet temperature,extrusion speed and friction coefficient,the grain uniformity is firstly improved and then deteriorated.Larger extrusion ratio leads to more uniform grain distribution.With the increase of initial billet temperature,the average grain size of the pipe first decreases and then increases.Additionally,larger extrusion ratio can bring smaller average grain size.The extrusion speed and friction coefficient have slight effects on the average grain size of the extruded pipe.展开更多
文摘A heat resistant aluminum alloy pipe blank with dimensions of d 700/300 mm×1 200 mm was prepared by the multi layer spray deposition technology. Optical microscopy, X ray diffractometry and transmission electron microscopy were used to analyze its morphologies and microstructures. The results show that the microstructures of the pipe blank are homogeneous and the precipitates are uniformly distributed d 25～70 nm spherical or sphere like Al 12 (Fe,V) 3Si particles, its mechanical properties at room temperature and 350 ℃ after densification by extrusion are σ b=412 MPa, δ =7.6% and σ b=187 MPa, δ =7.6%, respectively. The analyses indicate that the proper match of the motion rates of atomizer and substrate can produce deposited blanks with uniform thickness and relatively high cooling rate.
基金Project(2006AA03Z115)supported by the National Hi-tech Research and Development Program of ChinaProject(2006CB605203)supported by the National Basic Research Program of ChinaProject(50374012)supported by the National Natural Science Foundation of China
文摘Suitable microstructures required for semisolid casting were formed by using a vertical pipe.Different lengths of vertical pipe,slug dimensions and pouring time were used to investigate their influence on the microstructure of A356 alloy.The results indicate that at the same length of the vertical pipe,the morphology of the primary α(Al)gradually deteriorates by the enlargement in the slug size,but the deteriorating speed slows down with increasing pipe length.They also reveal that the increase in the pipe length improves the microstructure,whereas no further improvement appears when the pipe length reaches a certain value.The optimum length of the pipe obtained in the present work is 430 mm.The microstructure of larger slug poured at higher pouring temperature gets worse and it can be improved by moderately elongating pouring time.The relative mechanisms were also discussed.
文摘The copper-based shape memory alloy pipe joint was applied in the field of oil pipelines jointing as well as installing. It has many advantages than anything. In the paper, the basic principle and connection influence factors of copper-based shape memory alloy pipe joint were described. Experimental results shows the copper-based shape memory alloy pipe joints can be used in oilfield oil pipeline connection and it can solve the inner pipe joint corrosion damage problem by welding.
基金Project(2009ZX04005-031-11)supported by the Major National Science and Technology Special Project of ChinaProject(KP200911)supported by the Research Fund of State Key Laboratory of Solidification Processing of ChinaProject(B08040)supported by the"111"Project of China
文摘A thermal-mechanical and micro-macro coupled finite element（FE） model for the hot extrusion process of large-scale thick-walled Inconel 625 pipe was developed based on the DEFORM-2D platform.Then,the influence rules of the key extrusion parameters on the average grain size and grain uniformity of the extruded pipe were revealed.The results show that with the increase of initial billet temperature,extrusion speed and friction coefficient,the grain uniformity is firstly improved and then deteriorated.Larger extrusion ratio leads to more uniform grain distribution.With the increase of initial billet temperature,the average grain size of the pipe first decreases and then increases.Additionally,larger extrusion ratio can bring smaller average grain size.The extrusion speed and friction coefficient have slight effects on the average grain size of the extruded pipe.
