高性能模块式电磁屏蔽体的研制

介绍了高性能模块式电磁屏蔽体的屏蔽原理、设计原则以及结构特点,给出了测试结果,并说明了该屏蔽体在实际应用中所起到的重要作用。     

铝合金局部真空电子束焊接工艺研究

阐述了铝合金法兰环缝典型结构样件局部真空电子束焊接工艺试验的情况。分析了铝合金焊接气孔的产生原因及采取相应的工艺措施。研究出铝合金局部真空电子束焊接工艺。     

法兰环缝局部真空电子束焊接技术研究

叙述了局部真空电子束焊接的特点及其在国防工业和民用工业的应用前景，叙述了国内外局部真空电子束焊接的发展状况，介绍了自行研制的法兰环缝局部真空电子束焊接装置和它的主要技术指标，以及该设备研制已突破的关键技术。     

电子束焊缝自动跟踪系统设计

叙述了一种用于局部真空电子束圆形焊缝的自动跟踪系统的设计和试验过程。在局部真空电子束焊接精密结构件的圆形法兰焊缝时，由于加工偏差、工装累计误差等原因，出现电子枪回转中心与焊缝圆心不同心现象。使用本控制系统，使转台在起始位置时，用小束流电子束对准工件扫描，利用电子束在焊缝上和在工件上产生的二次电子数量不同而检测出焊缝起始点位置。利用相同工作原理，再用小束流对整条圆焊缝进行扫描，并由计算机实时记录整个圆形焊缝上各点与扫描线圈电流过零时电子束束斑间的偏差值，完成一个示教过程；然后由计算机处理与分析所获取的数据并存贮；在焊接时利用处理后的偏差值在圆形焊缝相应位置不断修正电子枪的位置，从而达到电子束束斑与焊缝自动对中的目的。     

SiC颗粒增强铝基复合材料的真空电子束焊接

针对SiCp/6061Al型复合材料进行了真空电子束焊接的初步探讨.试验结果表明:电子束电流越大,熔深越深;焊接速度越快,熔深越小;焊接过程中SiC颗粒会与液态铝发生界面反应,生成脆相Al4C3;镁元素的气化易导致焊缝气孔的生成.     

Axial effect analysis of relativistic electron beam propagation in vacuum

In geostationary orbits and other quasi-vacuum environments, relativistic electron beams are affected by the initial emittance and space charge effects during the propagation process, resulting in beam quality degradation. Furthermore, axial energy distribution change in the beam and the axial transient electromagnetic effect caused by current changes in the head and tail regions of the beam also cause the beam to expand and affect its quality. In this study, the particle-in-cell method was used to construct a long-range propagation model of a relativistic electron beam in a vacuum environment. By calculating and simulating the axial energy distribution of the beam and the changes in the transient electromagnetic field, the axial effect during the propagation process was analyzed, and the parameter change law of the effective propagation of the beam was explored. This provided a theoretical reference for a more accurate assessment of the beam quality during propagation.     

Mechanical properties of 9Cr–1W reduced activation ferritic martensitic steel weldment prepared by electron beam welding process

Microstructure and mechanical properties of the weldments prepared from 9Cr–1W reduced activation ferritic martensitic (RAFM) steel using electron beam welding (EBW) process were studied. Microstructure consists of tempered lath martensite where precipitates decorating the boundaries in post weld heat treated (PWHT) condition. Lath and precipitate sizes were found to be finer in the weld metal than in base metal. Accordingly, hardness of the weld metal was found to be higher than the base metal. Tensile strength of the cross weldment specimen was 684 MPa, which was comparable with the base metal tensile strength of 670 MPa. On the other hand, DBTT of 9Cr–1W weld metal in as-welded condition is similar to that reported for TIG weld metal in PWHT condition.     

A study of the influence of electron beam welding sequences on the ITER vacuum vessel prototype VATS

This paper presents a detailed finite element simulation of the welds of the prototype Vessel Advanced Technology Segment (VATS) by electron-beam welding. The flexible support housings are reinforcing cylinders of the pressure boundary of the ITER vacuum vessel. They connect inner and outer shells. Eight different simulation sequences were carried out to explain the different mechanisms that drive the distortion process during welding and to lead to an optimum sequence which minimizes the final distortions. The simulations were used to guide the manufacture of the final sequence of the VATS.     

大功率电子束轰击炉高压PWM电源的研制

介绍高压PWM-BUCK DC/DC变换器的工作原理,分析其工作特点,给出了应用于大功率轰击炉加速电源工程实践的技术路线.运行结果证明,高压PWM电源较之晶闸管移相调压控制的高压电源,具有输入电流谐波小、功率因素高及运行效率高等优点.