SiO2活性剂对不锈钢钨极氩弧焊电弧现象的影响

通过研究SiO2活性剂TIG焊焊接不锈钢过程中电弧形态、电弧电压及焊缝几何形状的变化,分析了SiO2活性剂钨极氩弧焊电弧等离子体形态、电弧空间电场强度、电弧温度、电弧电流密度及电弧力的影响.结果表明,SiO2活性剂使TIG焊电弧等离子体收缩,加热区域及电弧力更加集中,同时电弧空间电场强度、电弧温度及电流密度显著提高,导致焊缝几何形状变化,但焊道熔宽未发生明显变化.     

Novel hybrid method： pulse CO2 laser-TIG hybrid welding by coordinated control

0IntroductionRecently,laser-arc hybrid welding,as a rising spe-cial manufacture technology,has attracted more and moreinterest and attentions of some researchers and weldingcompanies.But,concerning laser-TIG hybrid welding,most of the research in this area mainly focused on contin-uous wave laser-TIG arc hybrid welding[1-3].In previousworks,because of the absorption and defocusing of laserenergy by hybrid arc plasma,the energy loss of laser wasvery serious when laser traversed arc in continu…     

电场提高激光-TIG复合焊熔深的机制

通过对比电场对单激光和单TIG焊接电弧在镁合金板材上堆焊熔深的影响,分析了外加电场对激光-TIG复合焊熔深的影响机制.同时通过研究在不同激光功率、不同TIG电流强度下电场的作用效果,对该机制进行了验证.结果表明,外加电场对激光-TIG复合焊熔深的作用是通过对激光小孔内等离子中带电粒子运动的控制来实现的.外加电场使小孔内电子向小孔底部运动时,可以增加焊接熔深;激光功率越大,外加电场增加熔深效果越明显;增大TIG焊接电流,削弱外加电场对熔深的增加作用.     

Investigation into arc constriction by active fluxes for tungsten inert gas welding

Abstract

Mechanisms by which active fluxes increase the penetration of conventional tungsten inert gas (TIG) welds (so called A-TIG welds) are reviewed. The most dominant mechanism for increased penetration is considered to be arc constriction rather than a change in the surface tension of the molten pool. An experimental programme of work was carried out using A-TIG flux in combination with a number of welding processes. The plasma process was investigated as it gives greater penetration than conventional TIG welding by increasing current density. The CO₂ laser and electron beam processes which do not rely on a current carrying arc as the heat source for welding were also investigated. Macrosections taken from the welds made by these processes showed that the A-TIG flux was only effective when the weld pool was produced by an arc or plasma. Where there was no arc or plasma present, the flux had little effect.     

Arc characteristics of laser-TIG double-side welding

Abstract

Based on the experiments of laser-TIG double-side welding (LTDSW) for aluminium alloys, the influence of laser radiation on the arc behaviours of the opposite side was investigated. Generally, with the variation of laser power, there are three typical arc shapes: arc column convergence, arc root constriction and arc expansion. An important point to notice is that the laser keyhole preheating will induce the arc column convergence in the LTDSW. The arc voltage in the LTDSW is lower than that in TIG welding over the entire range of the experimental currents. Moreover, with increasing welding current, the difference in arc voltage between TIG welding and LTDSW is diminished because of the self-stabilisation of the arc burning at high currents. The complex transformation of arc behaviours has a great effect on the arc current density and its stability. The laser generated hot spot or laser induced plasma will have a higher temperature and greater electron density than neighbouring regions, and will offer the line of least resistance or the lowest potential drop. Hence, it is very reasonable that the arc voltage should descend under the influence of laser radiation, and the arc electrons should compress and root to the hot spot or plasma zone.     

镁合金交流TIG和脉冲TIG组织性能分析

采用交流TIG和交流脉冲TIG两种焊接方法焊接变形镁合金AZ31B板材,利用高速摄像机和红外热像仪研究稳定焊接过程中的电弧形态和焊接温度场,观察焊接接头的微观组织并进行力学性能拉伸试验.发现脉冲焊接在峰值电流加热时的电弧形态明显大于交流TIG焊接时的电弧.对比焊接温度分布曲线可以看到,脉冲焊接时熔池两侧区域的冷却速度更快.脉冲焊接接头的热影响区更窄,而且晶粒更细小均匀.拉伸结果显示交流脉冲TIG焊接接头强度高于交流TIG焊接接头强度.     

厚壁焊接钛管的等离子填丝+脉冲TIG双枪焊接工艺研究

钛及钛合金厚壁焊管是海水淡化和海洋工程等行业的主要部件.采用前置直流等离子填丝+后置脉冲TIG电弧的双枪焊法,无耦合的等离子焊+TIG焊形式利用等离子弧焊与TIG焊的优点实现了大口径壁厚4 mm的TA1焊接钛管的优质、稳定焊接.结果表明,随着等离子气体流量的增加,直流等离子填丝焊的熔深增加,厚壁钛管全熔透;后置TIG电...     

等离子弧焊机的发展与前景

等离子弧是采用等离子焊炬压缩自由电弧,形成高温、高电离度和高能量密度的电弧,具有焊接质量高、焊接速度快、热量集中等特点.对比分析了等离子弧与TIG焊的差别.同时,分析了我国使用等离子孤焊机与国外使用量的差距,强调我国应大力发展通用型大电流等离子弧焊接设备,谁在大电流通用型等离弧焊机的研制方面走在前面,谁就站在了焊接时代的前沿.     

Research of welding arc electron density in hyperbaric TIG welding

The arc spectrum of TIG welding in high pressure was analyzed by Stark broadening.Using the characteristic line of ArI in welding arc,a study of electron density in high pressure revealed that the electron density of the welding arc had an upward trend with the pressure increase.According to data analysis,a curve of relationship between electron density and environmental pressure was established.It has a universal significance for change of electron density in high pressure.Through the analysis of electron density changing in time-domain in different pressure,a theoretical basis was provided for the problem of poor arc stability in high pressure.     

高频脉冲TIG焊电弧阳极行为的研究

本文首次测定了高频脉冲TIG焊电弧阳极的平均电流密度分布及其中心电流密度动态过程,研究其变化规律并建立了数学模型,从而探讨了高频脉冲TIG焊电弧的高频效应机理。实验研究表明高频脉冲TIG焊电弧阳极能量密度高于直流电弧,小电流时高频效应显著,适宜焊接精密超薄件,推荐脉冲频率为20kHz。