WANG Biao
,
JI Zhenping
,
LIU Wenhong
,
MA Jiaocheng
,
XIE Zhi
钢铁研究学报(英文版)
By means of Gleeble1500 dynamic thermomechanical simulator, the continuous casting process for HRB335C steel was simulated using solidifying method and hot ductility and strength of the steel were determined. The test results indicate that there are three temperature regions of brittleness for HRB335C billet in the temperature range from 700 ℃ to solidification point; the first temperature region of brittleness is 1 300 ℃ to solidification point of the billet, the second temperature region of brittleness is 1 200-1 000 ℃, and the third temperature region of brittleness is 700-850 ℃; the steel is plastic at 850-1 000 ℃. The cracking sensitivity was studied in the different temperature zones of the brittleness for steel HRB335C and the target surface temperature curve for the secondary cooling is determined. With optimized process, the mathematical model of the steady temperature field with twodimensional heat transfer for 150 mm×150 mm HRB335C steel billet was established to optimize the secondary cooling process. The conic relation of water distribution between secondary cooling water flux and casting speed is regressed. Keeping the surface temperature of billet before the straightening point above 1 000 ℃, the results of billet test indicate that there is free central shrinkage cavity. The billet defect is decreased greatly, and the quality of billet is obviously improved.
关键词:
continuous casting billet;brittle temperature zone;tensile strength;secondary cooling;simulation
LIU Wenhong
,
XIE Zhi
钢铁研究学报(英文版)
To improve billet quality and the trackability and stability of secondary cooling water during continuous casting, the superheat is introduced into the water distribution for secondary cooling to design the relevant control system, based on the water distribution model, superheat, surface temperature and fuzzy self-adaptive PID. A spray cooling system is thus set up for simulation test in laboratory to test the step signal from the conventional, integral separated and fuzzy self-adaptive PID controllers and the simulation casting. The simulation test results show that the fuzzy self-adaptive PID controller’s performance is better than the other two controllers, which provides a foundation for further study and application.
关键词:
fuzzy self-adaptive PID;continuous casting;secondary cooling;superheat
徐卫兵
,
戈明亮
,
何平笙
应用化学
doi:10.3969/j.issn.1000-0518.2001.09.011
用熔融插层法制备聚甲醛/蒙脱土纳米复合材料,用X射线衍射研究聚甲醛及复合材料的微观结构,表明复合材料是纳米复合材料.用DSC法研究其非等温结晶行为,对所得数据分别用Jeziorny法、Ozawa法和Liu法进行处理.结果表明,Jeziorny法和Liu法处理非等温结晶过程比较理想.聚甲醛及聚甲醛/有机蒙脱土纳米复合材料的结晶活化能分别为334.6和196.9 kJ/mol,说明有机蒙脱土的加入,降低了聚甲醛的结晶活化能,且t1/z缩短,起到了异相成核的作用.
关键词:
聚甲醛
,
蒙脱土
,
纳米复合材料
,
非等温结晶动力学
王平华
,
徐国永
应用化学
doi:10.3969/j.issn.1000-0518.2004.08.007
用熔融复合法制备聚丙烯/凹凸棒土纳米复合材料,用DSC法研究其非等温结晶行为,对所得的数据分别用Jeziorny法、Ozawa法和Liu法进行处理.结果表明,Jeziorny法和Liu法处理非等温结晶过程比较理想.聚丙烯及聚丙烯/凹凸棒土纳米复合材料的结晶活化能分别为194.1和162.8 kJ/mol,表明凹凸棒土的加入,降低了聚丙烯的结晶活化能,且t1/2缩短,起到了异相成核作用.
关键词:
聚丙烯
,
凹凸棒土
,
纳米复合材料
,
非等温结晶动力学
Scripta Materialia
A recent comment on a previously published paper addressed the invalid explanation of the off diagonal interdiflusion coefficients of the beta-Ni(Al,Cr) phase in the Ni-Cr-Al system according to the symmetric property of the thermodynamic matrix. In this paper, the experimental data presented by Hou et al. was reanalyzed and the interdiffusion coefficient matrix was estimated again. The results of the analysis have been discussed in terms of a brief reply to the comments of Liu and Liang. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
关键词:
Diffusion;Intermetallic compound;Ni-Cr-Al
邓超
,
邵玮
,
李春忠
高分子材料科学与工程
采用元机纳米锑掺杂二氧化锡(ATO)和有机聚醚酯(PEE)协同提高聚时苯二甲酸乙二酯(PET)的抗静电性能,合成了聚对苯二甲酸乙二酯-聚醚酯/锑掺杂二氧化锡纳米复合材料(PET-PEE/ATO).使用Czawa方程和Liu-Mo方程研究了PET-PEE/ATO纳米复合材料的非等温结晶过程.Ozawa方程研究发现,在非等温结晶过程中,PET、PET-PEE、PET/ATO、PET-PEE/ATO的成核性能依次提高.Liu-Mo方程发现,ATO和PEE的加入分别促进了异相成核作用和加快了结晶生长,PET-PEE/ATO结晶成核性能最好,结晶速率最快.
关键词:
聚对苯二甲酸乙二酯
,
有机聚醚酯
,
无机纳米锑掺杂二氧化锡
,
纳米复合材料
,
非等温结晶动力学
周晓宏
,
刘红军
,
刘鹏
功能材料
优化技术是一种以数学为基础,可用来求解各种工程问题最优解的应用技术.本文利用磁流变阻尼器动态特性数据,采用遗传算法进行阻尼器模型参数识别优化过程,最终将得到的磁流变阻尼器模型参数用于土木工程结构振动控制研究.已建立的磁流变阻尼器的动力特性将在不同的电场强度和变化的位移幅度下进行测试,可以得到在不同位移和速度下恢复力的滞回曲线,建立Bouc-Wen模型.把根据试验得到的滞回曲线和使用遗传算法对模型参数进行优化的结果进行比较可知,这种模型的参数可以以十分小的误差得到优化.
关键词:
遗传算法
,
阻尼器
,
参数识别
吕友军
,
董旭斌
,
张天宁
工程热物理学报
本文采用基于颗粒动力学的欧拉双流体模型,对比研究了曳力和湍流对超临界水流化床传热特性的影响,选取了Gidaspow、Syamlal-O'Brien和Wen-Yu三种曳力模型以及标准κ-ε、RNG κ-ε、Realizable κ-ε湍流模型三种高Re数湍流模型及低Re数κ-ε湍流模型.研究结果表明,在三种曳力模型中,Gidaspow曳力模型在超临界水流化床中更为适用;对于所采用的四种κ-ε湍流模型,利用三种高雷诺数湍流模型模拟所得床层与壁面间传热系数基本一致且大于采用低雷诺数模型模拟所得传热系数,而综合考虑,RNGκ-s湍流模型更适于超临水流化床传热特性的研究.
关键词:
超临界水流化床
,
曳力
,
湍流
,
传热
