脱壳穿甲弹穿甲后效试验评估方法探讨

本文以尾翼稳定脱壳穿甲弹为主要研究对象,开展了穿甲弹穿甲后效试验技术与评估方法研究,重点解决目前穿甲弹后效试验评估标准不完善的问题．论文对脱壳穿甲弹后效作用的种类进行了研究,在此基础上建立和完善了装甲目标毁伤效应评估方法．     

穿孔效率与能耗的建模与综合优化

 对于无缝钢管穿孔生产,穿孔效率和穿孔能耗是衡量生产的两个重要指标。但由于其影响因素复杂,难以建立机制模型,故难以实现对其模型的综合优化。为实现穿孔效率和穿孔能耗的综合优化,根据穿孔生产工艺将穿孔过程分成3个部分,提出了基于均值子时段MICR方法的穿孔效率和穿孔能耗的预报模型。在预报模型的基础上,采用遗传算法对各段工艺参数的平均值进行寻优,得到穿孔效率和穿孔能耗综合优化结果。仿真和试验结果表明,基于穿孔效率和穿孔能耗预报模型的优化方法可有效取得最优工艺参数,为穿孔效率的提高和穿孔能耗的降低提供依据。     

Research on technology of twin rollers rotary forging of spiral bevel gears

Abstract

To investigate the technology of twin rollers rotary forging of spiral bevel gears, three different models, which are the open die, the closed die and the floating die model, were designed to rotary forge a big spiral bevel gear whose external diameter is 246?mm. The effects of the spiral bevel gears that formed in the three models were analysed by three-dimensional finite element method under the commercial software DEFORM 3D. Finally, experiments have been carried out on a 20CrMnTi gear billet to compare the numerical results. The simulation results are in good agreement with the experimental ones and demonstrate that the floating die is the optimal model to rotary forge the spiral bevel gear, the microstructure of the gear that formed by rotary forging is refined well, and the microhardness reaches 457.8?HV (an increase of 110.0?HV) compared with the gear that formed by machining. These results provided a scientific basis for actual production of the spiral bevel gear.     

Biomass reducing agent utilisation in rotary hearth furnace process for DRI production

Abstract

This study aims to provide a theoretical and technical basis for utilisation of biomass (bamboo char, charcoal and straw fibre) in the rotary hearth furnace process to produce direct reduced iron. Each biomass material has strengths and weaknesses. The bamboo char pellets possess high fixed carbon content, but the lower strength and the expansion rate of pellets make it difficult to reach production requirements. Although the charcoal based pellets are similar to coal based pellets, their strength is the lowest of these reducing agents. The straw fibre based pellets possess high strength and large volume shrinkage, but the low fixed carbon content results in low productivity. Using biomass in a combination of these alternatives can enable coal to be replaced and produce pellets with a higher metallization than with coal.     

冷连轧机组中转鼓式飞剪设计改造

转鼓式飞剪是板带材连续生产线上的一种在线剪切设备,通过对剪刃型式的选择减小了剪刃的最大剪切力,对其齿轮结构优化设计消除了传动斜齿间的问隙,提高了飞剪剪切的平稳性和剪切质量;同时通过安装飞轮,减小了剪切时尖峰负荷对电机的冲击,使电机选用更合理同时也起到了节能作用,为飞剪的设计提供了参考。     

可双向多次剪切的转鼓式飞剪设计

介绍了单向剪切转鼓式飞剪的结构现状,结合双向多次剪切转鼓式飞剪的工艺设计需求分析,从中归纳出双向多次剪切功能实现的基本要求,在此基础上重点讨论了双向多次剪切转鼓式飞剪的结构设计及其控制方法,并依托飞剪的能量转化模型对飞剪的力能参数进行了计算。分析表明,这种新型的转鼓式飞剪结构合理,不仅能满足炉卷和中厚板组合生产线双向、每向多次剪切的功能要求,同时能满足生产线的快速生产节奏的工艺需求。通过设计讨论,为双向多次剪切的转鼓式飞剪设计研究提供一些思路和方法,同时为轧钢工艺人员的选型应用提供参考。     

大厂浮选锡中矿回转窑硫化挥发的研究

采用回转窑硫化挥发法处理大厂矿务局浮选锡中矿，考察了焙烧温度、时间及配料量等因素对锡挥发率的影响，取得了锡挥发率９８％、焙球残锡０．１４％的试验结果     

钛及钛合金管加工工艺探讨

主要介绍了钛管穿孔现阶段的主要加工工艺及其特点,通过二次穿孔在不锈钢中的运用和钛管实际生产过程中的问题．提出对钛管进行二次穿孔的研究。     

R290旋转式压缩机最小安全粘度研究

作为一种环保制冷剂,R290具有温室效应指数(GWP)小的特点,适合应用于房间空调系统。制冷剂替代的同时,必须要保证旋转式压缩机滑动部(尤其是轴承)的润滑状态良好,以避免发生咬合,甚至磨损。为了确保轴承的可靠性,传统的方法是保证油池温度与冷凝温度的温差大于零。这是保证最小安全粘度的替代措施,以确保足够的轴承油膜厚度。本文基于轴承油膜厚度计算理论,介绍了一种高背压R290旋转式压缩机最小安全粘度的确定方法,找出轴承润滑最恶劣的工况。     

S波段双通道高功率波导旋转关节的研制

介绍了一种S波段双通道高功率波导旋转关节,对旋转关节的结构组成、关键尺寸选择、模式匹配及通道间隔离设计等进行了详细的分析和研究.仿真分析和测试结果表明,在10%的带宽内,旋转关节电压驻波比小于1.1,驻波转动起伏小于0.02;插入损耗小于0.2dB,插入损耗转动起伏小于0.02dB,通道间隔离度大于85dB,双通道功率容量均超过1MW.通过对比,旋转关节各项性能指标均达到国外同类产品的先进水平,同时结构形式简单,加工调试方便,可广泛应用于雷达及微波系统中.