Numerical simulation of solidification structure of high carbon SWRH77B billet based on the CAFE method

Abstract

Based on the coupled method of cellular automaton (CA) and finite element (FE), the solidification structure of 160×160 mm cast billet of high carbon SWRH77B steel was simulated. The nucleation density, kinetics of the dendrite tip growth, crystallographic orientation and coupling of CA and FE methods are discussed. In the current study, the influence of superheat on the solidification structure of the billet is researched in detail. The results show that for an increase in superheat extent from 20 to 30°C, the density of grain in billet decreased from 4·662×10⁶ to 3·087×10⁶ m^?2, and the grain mean radius increased from 295·1 to 346·3 μm. The three-dimensional microstructure of high carbon SWRH77B steel was simulated by the CAFE method, and there was good agreement with the results from industrial billet.     

凝固末端电磁搅拌对77B铸坯中心偏析的影响

77B铸坯在拉拔过程中常因塑性不足而发生拉断。通过电镜、低倍等对断裂的机理进行分析,最终确定使用凝固末端电磁搅拌器来消除铸坯的中心偏析。结果表明,经过末端电磁搅拌的连铸坯试样中心偏析程度基本上得到了改善,取得了较好的效果。     

Ф165mm HAl77-2铝黄铜铸锭生产试验

半连铸法生产普通黄铜的工艺已比较成熟,铸锭成材率较高,但是生产Ф165mm HAl77-2铝黄铜难度较大,铸锭质量容易产生横向裂纹、夹渣、冷隔及漏挂、放炮等问题。通过对铸锭生产的现场跟踪和工艺参数的不断调整及试验,优化了生产Ф165mm铝黄铜的工艺流程和操作规程,并制定了一些解决铸锭缺陷的措施。     

转基因甜菜GTSB77品系特异性实时荧光聚合酶链式反应检测方法建立

目的 为实现转基因甜菜GTSB77的标识管理,建立其品系特异性实时荧光聚合酶链式反应(PCR)检测方法。方法 针对GTSB77的3′端外源插入片段与甜菜基因组DNA之间的邻接区序列设计引物和探针,建立GTSB77品系特异性实时荧光PCR检测方法,并对该方法的特异性、灵敏度和重复性进行检测。结果 建立的GTSB77检测方法特异性强,定量限(LOQ)为16拷贝,扩增效率为102%,重复性测试结果相对标准偏差(RSD)介于0.21%～1.66%之间。结论 建立的实时荧光PCR方法可应用于GTSB77的鉴定检测。     

预应力钢丝及钢绞线用SWRH77B盘条拉拔断裂原因分析

分析预应力钢丝及钢绞线用SWRH77B盘条拉拔断裂原因.针对平齐状、杯锥状、斜茬状和不规则断口形貌及形成原因,提出改进措施:(1)合理配置连铸二冷工艺,正确调整末端电磁搅拌位置,避免中心偏析和缩孔的形成.(2)认真检查钢坯的表面质量,对有缺陷的坯料应进行修磨,较严重的坯料应回炉.(3)勤检查、更换导卫装置和轧槽,合理分...     

Standard FORTRAN 77 as a parallel language

There have been many attempts to use FORTRAN as a language environment for parallel processing. In each case either the standard has been violated or some facilities have been left lacking and in most cases both. This paper briefly examines some of the approaches to parallel processing in the FORTRAN environment, provides an interpretation of the FORTRAN 77 standard which supports a very flexible and complete parallel processing environment, and discusses some of the implications of this approach.     

淬火U0.77Zr0.23合金组织结构研究

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双串口CPU在"某型号导弹发射车电量测试系统"中的应用

本文介绍了双串口CPU W77E58在"某型号导弹发射车电量测试系统"中的应用.W77E58作为PC机与多个下位机之间通信的中转机构,大大简化了硬件电路,提高了整个系统工作的可靠性,使编程工作也简单易行.经过实际应用,获得了良好的预期效果,今后在类似的系统中有广阔的应用前景.     

真菌曲霉F77对水中Cs~+的吸附

微生物在环境放射性污染修复中具有广泛的应用前景。从放射性污染土壤中筛选出一株耐辐射真菌曲霉F77,研究了它对水中Cs+的吸附及其影响因素。结果表明:酸对Cs+在曲霉F77上的吸附存在竞争作用,pH=2.0~3.5溶液中的Cs+几乎不被曲霉F77吸附;曲霉F77生长过程中代谢产生大量的酸性物质;Cs+的吸附随着曲霉F77培养时间的增长而增大,在曲霉F77逐渐衰亡时吸附降低;K+质量浓度小于500mg/L时对Cs+在曲霉F77上的吸附没有影响,当K+质量浓度大于500mg/L时Cs+的吸附随K+浓度增大而减少;溶液中Cs+质量浓度为0~500mg/L范围内,曲霉F77对Cs+均有较高的吸附,Cs+质量浓度为500mg/L时,Cs+的吸附量为27.6mg/g。温度影响曲霉F77对Cs+吸附的快慢,不影响最后的吸附量;曲霉F77对Cs+具有较好的吸附性能,表明曲霉F77具有吸附剂的潜质。