焊接工艺参数对Q690D高强钢多层多道焊缝缺欠的影响

针对液压支架结构件用Q690D高强钢多层多道焊焊缝,通过焊缝横截面形貌分析、X射线检测等分析手段研究了焊接电流、保护气体流量、焊丝干伸长、坡口拼装间隙等焊接工艺参数对焊缝缺欠类型、位置与数量的影响,并通过拉伸试验、冲击试验测试了焊接接头性能。结果表明,液压支架结构件用Q690D高强钢多层多道焊焊缝中缺欠以气孔、未熔透和未熔合为主,其中气孔约占43%,未熔透约占30%,未熔合约占23%;缺欠主要集中于焊道根部、焊缝内、焊道与母材熔合线处、焊道之间等位置,其中,焊道根部缺欠数量约占54%,为焊缝缺欠最集中的位置;试验范围内,焊接电流、保护气流量、焊丝干伸长等参数对焊缝内部缺欠影响较大,而对焊缝根部缺欠无明显影响;拼接间隙对焊缝根部未熔透、气孔等缺欠有明显的影响作用,当拼接间隙为2mm时,可有效减少根部缺欠;保护气种类主要影响焊缝成形质量,而对焊缝缺欠无明显影响;优化工艺参数后,焊缝缺欠明显降低,无明显未熔透、未熔合等缺欠,气孔率约2.1%,接头抗拉强度达798.6MPa,接头性能良好。     

转向架耐候钢角接接头激光/激光-MAG复合焊工艺

为解决高速列车转向架耐候钢焊接构架中存在的焊缝根部未焊透问题,针对转向架焊接构架中典型的角接接头,采用激光/激光-MAG复合焊接技术进行系统的工艺试验,通过分析焊缝熔透及成形情况,确定适合激光/激光-MAG复合焊角接接头的坡口角度为35°、钝边尺寸为4 mm,以及相应焊接工艺参数。焊接接头无明显的淬硬组织,硬度测试结果满足相关标准规定。     

根部未焊透对搅拌摩擦焊接接头力学性能的影响

采用针长为2.6~3.1 mm的搅拌头对厚为3.2 mm的2024-T3铝合金进行搅拌摩擦焊接,通过金相观察、力学性能测试和断口扫描,研究了根部未焊透对接头性能的影响。研究结果表明,在固定工艺参数和压入量条件下,当搅拌针长度减小时,根部未焊透缺陷由弱连接线转变成弱连接线和残余原始对接线共同组成;当板厚与搅拌头长度差小于0.4 mm时,接头强度可达母材的80%以上;根据断口扫描结果可知,充分焊透的接头表现为韧性断裂形式,当根部出现未焊透缺陷时,接头塑性变形能力显著降低。     

焊接速度对AA6082搅拌摩擦焊接头根部 缺陷及性能的影响

研究了不同焊接速度对5.1 mm厚6082-T6铝合金搅拌摩擦焊接头根部缺陷及性能的影响.采用光学显微镜观察了不同参数下接头根部缺陷形貌并对不同焊接速度下的接头进行了拉伸和弯曲试验.结果表明,随着焊接速度的不断增加,接头根部未焊透缺陷倾向变大,接头软化区部位最低硬度值逐渐增高.焊接速度由50 mm/min增大到400 mm/min时,接头抗拉强度逐渐增加.进一步增大焊接速度到600 mm/min时,由于根部未焊透缺陷的严重性变大,造成接头强度下降.在软化区是接头薄弱区的条件下,其尺寸较小的根部缺陷不影响接头抗拉强度.但是对接头的抗弯强度有显著的不利影响.     

水工钢结构双面坡口机器人焊接工艺

基于弧焊机器人对接平焊双面不对称坡口焊接工艺,通过试验研究焊接电流、焊接速度等工艺参数对焊接质量的影响。结果发现:针对20mm厚Q345B热轧钢板不对称双边坡口,打底采用电流170A、焊接速度0.25 m/min时,焊缝成形良好,填充高度合适,焊缝背面根部成形良好;采用脉冲MAG焊接,电流245 A、焊接速度0.25 m/min时,背面焊缝根部完全熔透,焊缝热影响区未出现淬硬组织,且钝边处的熔宽由常规MAG焊的3 mm增加至5 mm,解决了水电水工钢结构行业焊接自动化应用不清根难以实现的工艺难题。     

坡口预留间隙对高强度钢厚板打底焊缝成形的影响

利用MSC. Marc有限元分析软件对低合金高强度钢厚板打底焊热过程进行数值模拟,从温度场角度分析坡口预留间隙大小对焊缝根部熔合的影响,并通过焊接试验对模拟结果进行验证和补充. 结果表明,在低合金高强度钢要求的焊接热输入下,当预留间隙小于2 mm时,打底焊缝根部出现未熔合或未焊透缺陷;当预留间隙增大到2~4 mm时,打底焊缝根部熔透,焊缝成形良好;当间隙增大到5 mm以上后,热源不足以熔化较多的侧壁母材金属,可能出现未熔合,实际焊接时需要采用大热输入摆动才能熔合良好.     

单面焊焊接接头超声检测缺陷自身高度的测定与模拟试验分析研究

介绍了单面焊焊接接头超声检测实际缺陷自身高度测定的对比试验,根据中厚板、厚板单面焊焊接接头根部可能产生的未熔合、未焊透缺陷自身高度的测定,采用模拟试验的有关数据加以分析。     

轨道车辆用铝合金横焊自动焊接技术

研究了动车组铝合金车体的横焊自动焊技术,通过Fronius专机进行焊接工艺试验,分析了焊缝下坠、焊缝表面发黑与根部气孔、焊缝熔合不良、未焊透等焊接缺陷产生的原因,制订了合理的工艺措施,有效保证了焊接质量。工艺优化后焊接接头具有良好的力学性能,抗拉强度为192 MPa,断后伸长率为9.8%,弯曲试件合格,综合力学性能满足设计使用要求。     

轨道车辆不锈钢车体激光焊部分熔透搭接接头焊接痕迹研究

根据部分熔透搭接激光焊工艺特点和结合不锈钢车体侧墙结构,采用不同规格厚度及表面加工类型组合及不同激光焊工艺进行试件焊接,焊后目视检测焊接痕迹的可接受性.试验结果表明:下板至少需选择2.0mm及以上厚度,焊接方向与拉丝方向相同时焊接后未焊接侧外观质量最好;下板熔深s在0.3～0.6mm时,厚2.0 mm下板未焊接侧外观美...     

电站P91管道焊缝根部的相控阵检测工艺探究

针对电站P91管道常见的焊缝根部缺陷,设计了具有相应缺陷反射体的模拟对比试块,对焊缝根部进行相控阵检测工艺的研究和验证。结果表明,制定的焊缝根部相控阵检测工艺对管道焊缝根部裂纹、根部未焊透和根部未熔合缺陷具有较好的检出效果,能检测出0.5 mm深根部裂纹、1 mm深根部未熔合和1 mm深的根部未焊透缺陷。将根部区域置于40°～45°声束角度范围内进行扫查可获得较好的根部缺陷的检测效果。此检测工艺在电站管道的监督检验中具有较好的推广应用价值。     

弧偏吹对埋弧焊接质量的影响和焊接工艺改进措施

为避免埋弧焊接过程中产生未熔合、未焊透和条状夹渣等危害性缺陷。提高埋弧焊接质量。探讨了直流弧焊电源埋弧焊接时弧偏吹现象的产生机理．分析阐述了埋弧焊接过程中条状缺陷的形成原因、弧偏吹产生的条件及弧偏吹对埋弧焊接质量的影响，并以此为指导。改进对接焊缝和熔透T形焊缝的埋弧焊接工艺。经推广应用．效果理想，经济效益显著。     

厚板双TIG打底焊缝根部熔合的数值模拟

建立了厚板双面双TIG打底焊有限元模型,并通过焊接试验验证该模型的合理性及准确性.在此基础上分别对不同错边及钝边的坡口形式下厚板打底焊温度场进行了模拟.结果表明,随着预留间隙的增大,双弧打底焊可熔化的钝边量增大,可允许的错边范围先增大后减小;在厚板打底焊时,当钝边及错边之和不超过4 mm时预留2~4 mm的间隙能够得到根部熔合良好的焊缝;存在的错边及钝边量之和超过6 mm将产生未焊透缺陷;当钝边及错边之和在4~6 mm之间时打底焊缝根部熔合情况随着间隙改变而变化.     

Experimental study on welding characteristics of CO2 laser TIG hybrid welding process

Abstract

The experiments of CO₂ laser TIG paraxial hybrid welding with 4 mm thick AISI 321 stainless steel sheet have been performed. The arc images and welding characteristics have been investigated with different energy ratios between laser and arc. The experimental results indicate that the hybrid welding is similar to laser welding and has also two welding mechanisms: deep penetration welding and heat conduction welding. Because of the effect of keyhole induced by laser, the arc root can be stabilised and compressed, and the current density and the penetration depth are all increased significantly, which show the characteristics of deep penetration welding. However, when the current is increased to a critical value, the laser induced keyhole disappears and the arc expands obviously, which decreases the penetration depth, so that the welding mechanism has been changed from deep penetration welding to heat conduction welding. Furthermore, the effects of distance between laser beam and electrode, pulsed laser and hybrid manners on hybrid welding characteristics have also been studied.     

电弧弧长对激光-电弧复合焊飞溅和底部驼峰的影响

由于热源形式的特殊性,激光-电弧复合焊接过程中激光和电弧间易发生相互干扰,产生飞溅和底部驼峰等缺陷。以590 MPa级船用高强钢为研究对象,研究了电弧弧长对激光-电弧复合焊飞溅和焊缝底部驼峰的影响。为了深入研究激光-电弧复合焊飞溅和底部驼峰的产生机理,利用高速摄像设备对熔滴过渡行为和焊缝底部熔池进行了观察。结果表明,适当缩短电弧弧长可以降低激光和电弧间的相互干扰,提高复合焊接过程的稳定性,进而降低飞溅产生的倾向。底部驼峰是小孔熔透性差和底部熔池流动不连续所引起的。缩短电弧弧长可以对底部驼峰的产生起到抑制作用,这是因为缩短电弧弧长可以降低等离子体对激光的吸收,提高激光的能量利用率,增加小孔熔透性和稳定性。创新点： 研究了电弧弧长对激光-电弧复合焊飞溅和底部驼峰的影响,采用高速摄像方法对底部熔池流动进行了观察,进一步明确了激光-电弧复合焊接焊缝底部驼峰的产生原因。     

基于弧压反馈的薄板GTAW智能熔透控制

薄板GTAW的熔透控制是保障其焊接质量的关键,而焊接熔透的智能传感与识别是其中的核心难题. 传统的焊缝背面直接视觉传感可以有效提取熔透控制信息,但是往往因为可达性受限而不能使用. 因此,文中对基于GTAW弧压电信号的传感焊接熔透进行研究,基于弧压反馈提取焊接熔透信号,进而调节焊接电流波形保证焊缝均匀熔透而不发生烧穿. 试验采用4 mm厚热轧钢板、3 mm厚冷轧钢板进行表面堆焊. 结果表明,在不同电流形式下堆焊试验中验证了控制原理,反馈智能调节,变散热条件以及变间隙试验均可得到较美观的焊缝.     

Closed-loop control of weld penetration in keyhole plasma arc welding

To improve the penetrating ability and the welding quality of keyhole plasma arc welding, a novel penetration closed-loop control system was established. In the system, welding current and plasma gas flow rate were selected as adjusting variables. The wavelet method was used to detect penetration status from welding arc voltage in real-time. The control strategy of one-keyhole-per-pulse was adapted to fulfill stable and high quality welding process. Experimental results show that the developed system can apparently increase the penetrating force of plasma arc and keyhole plasma arc welding is realized successfully in stainless steel with 10 mm in thickness. Moreover,the disturbances of gradual change and break change from 3mm to 6mm in thickness are come over due to the good response property of the developed system.     

Hybrid laser arc welding of X80 and X120 steel grade

The aim of the present work was to investigate the possibilities of hybrid laser arc welding regarding reliable production of longitudinal welds of high strength pipe steels X80 and X120 and to evaluate achievable mechanical properties of laser hybrid welds. The study focused on weld toughness examination in low temperature range up to ?60°C. Suitable filler materials were identified in the context of this task. It could be shown that metal cored electrodes guaranteed sufficient Charpy impact toughness at low temperature for both investigated materials. Modern arc welding technologies such as modified pulsed spray arc were used to promote deeper penetration of the filler material into the narrow laser welding gap. Edge preparation with a 14 mm deep root face was considered as optimum, because no penetration of the filler material could be detected beyond this depth limit, and therefore, any metallurgical influences on the weld metal properties through the welding wire could be excluded.     

Electrode tips geometry and penetrating in narrow gap welding

Abstract

The problem of sidewall incomplete fusion in narrow gap tungsten inert gas (TIG) welding could be well solved when the proper magnetic field was added. However, the various tungsten electrode tips seriously affect the distribution of arc pressure and the quality of welding seams. In addition, it is a 350 A GTA, as this is in a regime in which finger penetration is common. This paper studies the distribution of arc pressure of five different styles of tungsten electrode tips: 30° circular cone, 60° circular cone, 60° circular cone with truncated cone of 2 mm diameter, terrace of 2×2 mm and terrace of 2×0·8 mm with the same welding parameters. The character of arc pressure is verified by assaying the seam cross-section under the controlling magnetic field condition in narrow gap welding. The measuring equipment that we designed independently is creative and applicative in narrow gap TIG welding under magnetic fields.     

焊接工艺参数对不锈钢A-TIG焊焊缝熔深的影响

利用自制的活性剂,考察了焊接工艺参数对奥氏体不锈钢A-TIG焊焊缝熔深的影响.结果表明:活性剂能使电弧收缩,穿透力增强,使焊缝熔深增加.在其它焊接参数不变的情况下,随着焊接电流的增加熔深增大;随着焊接速度的增加熔深减小;焊接电弧长度由2mm增加到3mm,焊缝熔深增大;由3mm增加到4mm,焊缝熔深减小.电弧收缩理论可以较好地解释试验结果.     

Real-time monitoring of weld penetration quality in roboticarc welding process

It is of great significance to develop an intelligent monitoring system for weld penetration defects such as incomplete penetration and burn-through in real-time during robotic arc welding process. In this paper, robotic gas metal arc welding experiments are carried out on the mild steel test pieces with Vee-type groove. Through-the-arc sensing method is used to capture the transient values of the welding voltage and current. The raw data of the captured welding current and voltage are processed statistically, and the feature vector S10 is extracted to correlate the welding conditions to the weld penetration information. It lays foundation for intelligent monitoring of weld quality in robotic arc welding.