不同焊接方法下燃料元件包壳用ODS钢焊接接头界面演化规律

ODS钢具有优异的高温力学性能、抗辐照性能和抗热蠕变性能等,是最有潜力的下一代核反应堆包壳候选材料之一。ODS钢的焊接技术主要包括熔焊、钎焊、压力焊等,根据核燃料元件包壳结构,选择电子束焊接、旋转摩擦焊及脉冲电流辅助扩散焊三种焊接方法进行对比研究,并对ODS钢焊接接头微观形貌演化进行分析,揭示了最优焊接方法及界面形貌演化规律。结果表明,电子束焊接及旋转摩擦焊接工艺下,焊接接头的晶界处均有Y_(2)O_(3)析出,而采用脉冲电流辅助扩散焊无氧化物析出和团聚,对于Fe-Cr系ODS钢有突出优势。因此,脉冲电流辅助扩散焊在抑制ODS钢中纳米氧化物的析出、团聚和减少接头变形等方面具有显著优势,是一种适合ODS钢焊接的高质量焊接方法。

基于Solid Edge的管件焊接元件参数化设计

针对管件柔性夹具中常用的焊接元件,本文介绍了管件焊接元件的参数化设计原理,即采用交互式方法获取元件的相关特征参数,并应用Visual Basic语言调用Solid Edge软件平台对管件焊接元件进行参数化设计,系统显著提高了管件焊接元件的设计效率。

高压设备用焊接密封元件的有限元分析

为了研究焊接密封元件在高压环境下的密封性能,本文应用ANSYS软件对圆形空腔式、焊环式和卵形空腔式焊接密封元件进行有限元分析,得出如下结论:根据等效应力值和应变值,给出三种焊接密封元件的危险截面,且密封元件的应力与密封元件的焊唇长度及焊环的密封焊位置密切相关;通过对三种焊接密封元件进行应力线性化分析,可知三种密封元件均满足强度要求。

无铅焊接元件的发展动态

在焊锡中排除铅必须适应整个焊接过程、质量检验、部分甚至设计组件的各种要求。

高可靠厚膜混合集成电路工艺研究

根据亚宇航级（K1级）的标准要求，进行了元件焊接、键合、衬底焊接等工艺研究，解决了多芯片真空／气氛炉共晶焊、无源元件再流焊、金一金键合、铝一钯银键合的高可靠性互连，以及真空／气氛加压共晶焊的高可靠粘接的工艺难题，形成了先高温后低温的的工艺加工流程，达到了预期的目的。

印制电路焊盘表面修饰对焊点IMC生长状态影响的研究

在印制电路板(Printed Circuit Board, PCB)产品的二级封装环节,使用焊料将元件焊接到焊盘过程中形成的焊点互连结构成为实现产品完整机械连接及电气、热通道的重要载体。其中焊料和焊盘间的界面反应影响着焊点内部金属间化合物(Intermetallic Compounds, IMC)的形成与生长,直接关系到电子元件的焊接质量与服役寿命。为此重点探究了IMC层经过三种焊盘金属表面修饰形成的形貌结构及热力学条件下的微观组织生长行为。通过恒温热处理分析服役过程中的IMC层演变规律,推力测试对比出不同焊盘基底的焊点结合强度,并确定IMC缺陷结构的失效源。对分析服役状态下焊点互连结构的失效机制,优化焊接工艺和提升产品质量有着重要的指导意义。

Simulation of hydrogen diffusion in welded joint of X80 pipeline steel

Hydrogen diffusion coefficients of different regions in the welded joint of X80 pipeline steel were measured using the electro-chemical permeation technique. Using ABAQUS software, hydrogen diffusion in X80 pipeline steel welded joint was studied in consideration of the inhomogeneity of the welding zone, and temperature-dependent thermo-physical and mechanical properties of the metals. A three dimensional finite element model was developed and a coupled thermo-mechanical-diffusion analysis was performed. Hydrogen concentration distribution across the welded joint was obtained. It is found that the postweld residual hydrogen exhibits a non-uniform distribution across the welded joint. A maximum equivalent stress occurs in the immediate vicinity of the weld metal. The heat affected zone has the highest hydrogen concentration level, followed by the weld zone and the base metal.Simulation results are well consistent with theoretical analysis.

Mapping relationship analysis of welding assembly properties for thin-walled parts with finite element and machine learning algorithm

The finite element(FE)-based simulation of welding characteristics was carried out to explore the relationship among welding assembly properties for the parallel T-shaped thin-walled parts of an antenna structure.The effects of welding direction,clamping,fixture release time,fixed constraints,and welding sequences on these properties were analyzed,and the mapping relationship among welding characteristics was thoroughly examined.Different machine learning algorithms,including the generalized regression neural network(GRNN),wavelet neural network(WNN),and fuzzy neural network(FNN),are used to predict the multiple welding properties of thin-walled parts to mirror their variation trend and verify the correctness of the mapping relationship.Compared with those from GRNN and WNN,the maximum mean relative errors for the predicted values of deformation,temperature,and residual stress with FNN were less than 4.8%,1.4%,and 4.4%,respectively.These results indicate that FNN generated the best predicted welding characteristics.Analysis under various welding conditions also shows a mapping relationship among welding deformation,temperature,and residual stress over a period of time.This finding further provides a paramount basis for the control of welding assembly errors of an antenna structure in the future.

自动光学检测技术在工业质量检测中的应用

以电子元件焊接质量检测为例,分析了自动光学检测技术在工业质量检测中的应用。在电子元件质量检测中应用自动光学检测技术,先采集待检测电路板图像,然后采用并行阈值化分割算法对图像去噪处理,获得二值图像,识别漏焊、短路、孔洞(缩锡)焊点。自动化光学检测技术的应用提高可电子元件焊接质量检测的精度和效率。