The 3-D traction field in the pressure screw-pair of a 3 500 heavy and mediumplate mill press down system is successfully calculated by applying the 3-D frictional contactmultipole-BEM and the corresponding program th...The 3-D traction field in the pressure screw-pair of a 3 500 heavy and mediumplate mill press down system is successfully calculated by applying the 3-D frictional contactmultipole-BEM and the corresponding program that has been developed. The computing results show themedium diameter orientation is unreliable, especially under the interference of an outer forcecouple. Under such working conditions, the circumferential traction distribution on the screw teethis extremely uneven, which is the main reason for the destruction and short life time ofscrew-pairs. When utilizing the same precision (the relative tolerance is 10X10^(-5)), themultipole-BEM uses almost the same CPU time as used by the FEM, but the needed computer memory sizeis only one eightieth of that needed by the FEM (10 MB vs. 800 MB). The multipole-BEM is well suitedfor computing large-scale engineering problems.展开更多
Study on cleanliness of high quality steels in 100t basic oxygen furnace was carried out by "Hot Metal Desulphurization-Basic Oxygen Furnace-Ladle Furnace Refining-RH Refining-Continuous Casting" process. Hi...Study on cleanliness of high quality steels in 100t basic oxygen furnace was carried out by "Hot Metal Desulphurization-Basic Oxygen Furnace-Ladle Furnace Refining-RH Refining-Continuous Casting" process. High-quality low-carbon ultra thick slabs were produced with 0.04%≤wC≤0.08%, wS≤0.002%, wP≤0.008%, wN≤0.004%, wH≤ 0.0002%, wT[O] ≤0.0015%. A series of key technologies for content control of carbon, phosphorus, sulfur, nitrogen, hydrogen and inclusions were determined, which has laid a foundation for the development of the high-degree steel.展开更多
基金This project is supported by National Natural Science Foundation of China(No.50075075) National "Ten-Five" Science and Technology Project of China(No.ZZ 01-13A-02-02-03). J
文摘The 3-D traction field in the pressure screw-pair of a 3 500 heavy and mediumplate mill press down system is successfully calculated by applying the 3-D frictional contactmultipole-BEM and the corresponding program that has been developed. The computing results show themedium diameter orientation is unreliable, especially under the interference of an outer forcecouple. Under such working conditions, the circumferential traction distribution on the screw teethis extremely uneven, which is the main reason for the destruction and short life time ofscrew-pairs. When utilizing the same precision (the relative tolerance is 10X10^(-5)), themultipole-BEM uses almost the same CPU time as used by the FEM, but the needed computer memory sizeis only one eightieth of that needed by the FEM (10 MB vs. 800 MB). The multipole-BEM is well suitedfor computing large-scale engineering problems.
文摘Study on cleanliness of high quality steels in 100t basic oxygen furnace was carried out by "Hot Metal Desulphurization-Basic Oxygen Furnace-Ladle Furnace Refining-RH Refining-Continuous Casting" process. High-quality low-carbon ultra thick slabs were produced with 0.04%≤wC≤0.08%, wS≤0.002%, wP≤0.008%, wN≤0.004%, wH≤ 0.0002%, wT[O] ≤0.0015%. A series of key technologies for content control of carbon, phosphorus, sulfur, nitrogen, hydrogen and inclusions were determined, which has laid a foundation for the development of the high-degree steel.
