HT-7U真空室振动时效消应力分析

针对HT-7U真空室拼焊过程中产生的焊接变形, 应用振动时效(VSR)工艺, 以消除拼焊处残 余应力, 提高真空室的尺寸精度. 通过振动过程中动应力分析和VSR工艺前后残余应力的对 比测量, 了解真空室拼焊处动应力和残余应力的分布状况, 实验结果表明VSR工艺消应力效 果良好.     

A633D斗杆的疲劳裂纹形成寿命

分析了A633D钢焊接接头在循环哉荷下的疲劳特性,进行了疲劳特性和静态拉伸实验,得到了该材料的静力参数,常规机械性能,焊接接头的循环σ-ε曲线以及焊接接头的应变寿命曲线,将局部应力－应变法用于该材料的10m3斗杆的裂纹形成寿命的估算,采用Miner法则结合概率的方法计算了不同可靠度下的疲劳寿命,其间考虑了焊接残余应力的影响,得出了焊接残余应力的存在使斗杆的裂纹形成寿命降低约10％。     

Deposition of carbon nitride films for space application

Carbon nitride thin films were prepared by electron-beam evaporation assisted with nitrogen ion bombardment and TiN/CN_x composite films were by unbalanced dc magnetron sputtering, respectively. It was found that the sputtered films were better than the evaporated films in hardness and adhesion. The experiments of atomic oxygen action, cold welding, friction and wearing were emphasized, and the results proved that the sputtered TiN/CN_x composite films were suitable for space application.     

宽幅钢箱梁环焊缝焊接顺序优化研究

基于热弹塑性有限元法,采用ANSYS软件建立了网格疏密过渡的单箱五室钢箱梁壳单元模型;结合高效的分段移动热源,实现了对大型复杂长焊缝结构焊接全过程的数值模拟,并定性对比了宽幅钢箱梁在不同的环焊缝焊接顺序下顶板和底板的变形情况.分析结果表明:腹板焊缝的焊接顺序对竖向最大变形值(绝对值)的影响不大,其值主要取决于顶板和底板...     

中国聚变工程实验堆水冷包层钢构件流道成形控制研究

针对CFETR水冷包层流道钢构件热等静压制备时易变形压塌问题,利用单轴扩散焊设备开展了焊接工艺参数优化试验。在此基础上,重新设计了流道焊接界面位置和尺寸,用两步热等静压扩散焊法制备出了流道变形可控的平板型第一壁钢构件模块。优化试验表明,低活化钢试样的固相扩散焊温度需高于950℃,焊后经过760℃/60min回火热处理试样力学性能可以得到有效回复。     

Photothermal Welding,Melting, and Patterned Expansion of Nonwoven Mats of Polymer Nanofibers for Biomedical and Printing Applications

We report a simple method for the photothermal welding of nonwoven mats of electrospun nanofibers by introducing a near‐infrared (NIR) dye such as indocyanine green. By leveraging the strong photothermal effect of the dye, the nanofibers can be readily welded at their cross points or even over‐welded (i.e., melted and/or fused together) to transform the porous mat into a solid film upon exposure to a NIR laser. While welding at the cross points greatly improves the mechanical strength of a nonwoven mat of nanofibers, melting and fusion of the nanofibers can be employed to fabricate a novel class of photothermal papers for laser writing or printing without chemicals or toner particles. By using a photomask, we can integrate photothermal welding with the gas foaming technique to pattern and then expand nonwoven mats into 3D scaffolds with well‐defined structures. This method can be applied to different combinations of polymers and dyes, if they can be co‐dissolved in a suitable solvent for electrospinning.     

爆炸焊界面附近熔化层厚度估算

 爆炸焊接界面附近温升是由爆炸绝热压缩和畸形变形能沉积两者造成的。通过计算绝热压缩温升和畸形变形能沉积产生的温升，给出熔化判据，估计出了爆炸焊接界面熔化层的厚度。     

超声纸杯焊接技术

本文介绍一种超声纸杯焊接设备及焊接工艺。     

高热负荷下偏滤器材料的温度测量

用小试样模拟试验测试了不同功率密度下的材料表面温度分布。用热等静压焊接方法制作了钨为表面的模拟偏滤器材料小试样,用 25mm的电子束作为热源,在真空室中用 0.3mm的NiCr NiSi热电偶测量了2～9MW·m-2功率密度下材料表面的温度分布。结果发现在充分冷却的情况下,表面最高温度约400℃,钨铜焊缝处的平均温度达150℃。     

Neutron-absorption deformable boron-rich ferrous alloys

The structure of the eutectic-type iron-boron alloys (up to 3.5 wt% B) crystallized at various velocities has been studied. It was established that due to temperature increase a coarse structure of the eutectic Fe+Fe₂B transforms into a fine dendritic structure. High-temperature annealing leads to the destruction of columnar construction of the eutectic phase and boride dendrites subsequently transform into the inclusions of spherical shape. These processes are more active at high velocities leading to decrease of strength properties and increase of elasticity of the alloys. Such treatment makes possible hot repartition of the ingots from the alloys Fe+3%B through their forging so that the ingots can be rolled into 3-5 mm thick platelets. The obtained product may serve as a material applicable for the preparation of neutron-absorption protective constructions.