静滴法测定含钛生铁的表面张力

本文讨论了用静滴法测定液态生铁表面张力的若干技术问题,并测定了攀钢生铁的表面张力及温度,硅、硫和钛含量对生铁表面张力的影响。     

液压系统效率

农业机械随产品的更新换代,将广泛采用液压技术,在十分讲究经济效益的今天,必须提高液压系统的效率,减少无用功,降低能源消耗。液压系统效率是油泵轴输入的机械能     

混凝土坝冷却自适应控制的在线辨识

本文应用自动控制理论“自适应在线辨识”解决了混凝土大坝混凝土一、二期冷却的自动控制问题。通过预埋的电阻温度计实时量测温度,实时调节循环冷却水系统的流量和水温或是毋须进行通水,以便达到良好的冷却质量和经济节约的目的。     

Continuous electromagnetic separation of inclusion from aluminum melt using alternating current

A novel scheme about the continuous electromagnetic purification of aluminum melt was put forward based on the utilization of a square separation pipe and a 50 Hz alternating current to produce electromagnetic force. It is experimentally found that with electrical current of 400 A/cm^2, it takes only 10 s to remove 95% inclusion from aluminum melt. Comprehensive numerical simulations were carried out to investigate the dynamics mechanisms behind the process. The results show that the removal of inclusion is attributed to the cooperative effects of electromagnetic buoyancy and the secondary flow induced by the rotational electromagnetic force, and the removal efficient increases with the size of inclusion and the electrical current imposed. Theoretical predictions on the distribution and removal efficiency of inclusion were supported by the experiments.     

考虑材料参数的刚粘塑性有限元初始速度场自动生成方法

本文采用一种包含材料硬化指数ｎ和速率敏感性指数ｍ的刚粘塑性有限元模型，阶段硬化处理考虑到等效应力公与应变率有关，依据线粘性材料假设，提出了考虑材料参数ｎ、ｍ影响的刚粘塑性有限元初始速度场自动生成方法，改进了文献［３］方法。数值模拟结果与有关文献的计算和实验结果进行了比较，表明本文方法是有效的。     

磷对Ni3Al凝固组织的影响

磷(P)在Ni3Al中的溶解度很低，凝固过程中向剩余液体中偏聚，最终在晶界上析出富P相，凝固后期。P在剩余液体中的偏聚程度升高，降低形核率，抑制试样心部等轴晶的形成，促使试样外缘晶粒向心部延伸生长，增加柱状晶长度。P降低合金终凝温度，增如糊状区长度，阻碍液相补缩，增加形成疏松的倾向。P产生上述作用的根本原因是其降低固、液两相体积自由能差和原子跃迁穿过液／固界面的激活能。