金属丝棉结构在电焊烟尘处理中的过滤性能研究

电焊烟尘对人危害极大,必须加以净化才能排放到空气中.然而电焊作业烟尘量极大,由于过滤效率低,导致小型移动式电焊除尘器应用受到限制.为了更好地利用移动式除尘器净化电焊烟尘,研究高效过滤材料变得非常重要.通过数值模拟金属丝绵的除尘效率、过滤压力损失及残余压降等影响过滤性能的因素,将金属丝绵应用于移动式除尘器.为了更好地发挥金属丝绵的过滤性能,设计特殊的过滤结构,并在电焊烟尘除尘器中应用以提高除尘器的过滤效率.结果表明,金属丝绵应用于电焊除尘器可以获得理想的除尘效果,并且可以克服很多现有电焊除尘器的缺点.     

变光焊接眼护具响应时间定义分析

通过对不同标准的变光焊接眼护具响应时间定义分析，提出各标准定义及计算值的区别，以利于帮助消费者进行产品选择和企业对产品设计的改进。     

焊接车间烟尘特性及治理措施

焊接生产会产生烟尘,焊接烟尘给人体带来的危害是比较严重的,焊接烟尘的治理方法有多种,合理选用可使焊接生产变成绿色环保型作业.     

长期服役环境下城镇PE燃气管道电熔焊接界面结构与老化性能研究

目的 研究电熔焊接界面在长期服役期间的老化性能及其变化规律。方法 以服役30 a的PE燃气管道电熔焊接管件和新焊管件为样本,通过超声相控阵无损检测和解剖的方法分析焊接界面的结构性能,通过氧化诱导时间测试、红外光谱测试和结晶度测试对PE管的中间部位、焊接界面的老化行为进行对比研究。通过对服役焊接管件附近土壤进行分析,确定影响管件服役老化的化学介质。结果 长期服役的PE电熔焊接界面存在不同程度的结构缺陷,尤其在焊接界面处发生了明显的性能弱化。焊接界面的热氧稳定性和结晶性能均低于管材中间部位,而管材中间部位的性能则低于新焊界面。相比新焊管件,服役30 a的PE电熔焊接界面出现C—O—老化峰,发生一定程度老化。经检测,土壤中存在的胺类、酮类和醇类有机物(如十二烷基二甲基叔胺)具有显著的化学活性,会对PE材料产生老化作用。结论 土壤的温度及化学介质带来PE燃气管道电熔焊接部位C—O老化基团的产生,将破坏聚乙烯的结构规整性,导致其结晶度的下降,影响到了电熔焊接界面的力学结合性能。本研究证实了土壤环境对PE带来的负面影响,影响其使用寿命和安全性,应加强关注土壤环境对PE燃气管道的长期服役安全问题。     

Resistance mash welding for joining of copper conductors for electric motors

The automotive industry is developing designs and manufacturing processes for a new generation of electric motors intended for use in hybrid and electric vehicles. This paper is focused on using solid-state welding to join rectangular wires in the fabrication of motor stators. Resistance welding has not typically been applied to copper due to its very high electrical conductivity; however through optimization of the current and pressure profiles, excellent quality copper-to-copper joints have been demonstrated with a technique known as resistance mash welding. A better understanding of resistance mash welding characteristics will help advancements in its application for stators. The limitations of this application will be discussed.     

东黄复线虞河跨越管段焊接补强导致管道弯曲问题的分析

为了解决东黄复线虞河跨越管线补强采用传统的焊接补板所带来的管线承重增加和焊缝增加引起的管线弯曲变形问题,采用有限元分析软件对管道弯曲问题进行计算分析,认为管道应力集中最严重的东侧弯头,在运行压力为4MPa的情况下,弯头处最大Mises等效应力为钢材屈服强度的64．58％,满足GB50253-2003《输油管道工程设计规范》要求。但为增加安全,可采取再设立一个固定支撑等措施。     

Bitter coil design methodology for electromagnetic pulse metal processing techniques

Electromagnetic pulse metal processing techniques (EPMPT) such as welding, forming and cutting have proven to be an effective solution to specific manufacturing problems. A high pulse magnetic field coil is a critical part of these technologies and its design is a challenging task. This paper describes a Bitter coil design using a newly developed methodology for a simplified analytical calculation of the coil and complementary finite element models (FE) of different complexity. Based on the methodology a Belgian Welding Institute (BWI) Bitter coil has been designed and tested by means of short circuit experiments, impedance and B-field measurements. A good agreement between the calculated and the experimental design parameters was found.     

Improvement of welding heat source models for TIG-MIG hybrid welding process

Tungsten inert gas-metal inert gas (TIG-MIG) hybrid welding process is an effective way to improve welding productivity and quality due to advantages of the two processes. Mathematical analysis is crucial to fundamentally understand this synergetic welding process. In this study, based on experimental visualization of arc behaviors, some assumptions are proposed to deduce adaptive plane and volumetric heat source models separately for each involved welding method first. The influence of torch angles on distribution of temperature and geometry of weld bead are calculated and compared with experimental results. It shows that this developed algorithm of heat source can be employed to accurately predict welding process whether the electrode gun is slanted backward or forward to the direction of welding. Then TIG-MIG hybrid welding process is simulated and analyzed without considering the attractive or repulsive force of two arcs. The characteristic of TIG-MIG welding process is discussed compared to single MIG. It lays the foundation for the further research on the interaction of the two arcs during TIG-MIG hybrid welding.