Research on laser-arc hybrid welding technology for long-distance pipeline construction

In recent years, the research on pipeline laser-arc hybrid welding technology has been the important and difficult in the field of welding all over the world. China Petroleum Pipeline Research Institute Co. Ltd. has firstly developed pipeline laser-arc hybrid welding system in China, and executed the welding tests based on X70/X80 steel. Preliminary experiment results showed that hybrid welding could meet the requirements of related standards such as API1104,ASME,etc., the mechanical properties of girth seam are qualified in the case that there were no internal defects. With the development of high-power fiber laser and the continuous improvement of welding equipment, laser-arc hybrid welding technology for pipeline field welding will be available soon.

Influence of laser on arcs in alternate arcing during laser-twin-arc hybrid welding process

In this study, multi-information including spectrum, high-speed photograph and electrical signal was adopted to explore the coupling mechanism of alternate burning in laser-twin-arc welding process. Laser provides a conductive, stable plasma channel for arcs. Plasma radiation strengthened especially in the center of the arc after hybrid. High temperature plasma erupting from keyhole provides an upward reacting force which can prevent droplet from transfer. The charged particles consisted in high temperature plasma reduce the voltage that maintains arc ignition or burning. The results show that laser can influence the arc shape, prevent droplet transfer, reduce resistivity and stabilize arcs.

Low-power YAG laser/arc hybrid welding of AZ-based Mg alloy

The results of recent researches on the weldability of laser/arc hybrid welding of AZ-based Mg alloy was presented.Experiments were conducted with a low-power(500 W) Nd:YAG laser and a TIG arc.The synergic effects and mechanical properties of the Mg joints by laser/arc hybrid welding were investigated,and the interaction mechanism of laser to arc was also discussed.The results show that Mg alloys can be easily welded in similar and dissimilar joints by laser/arc hybrid welding technique.With the arc power increasing,a higher weld depth is obtained,and the weld depths for laser and arc acting in combination(laser/arc) are two times higher than that of the total of laser and arc acting separately(laser+arc) in optimal conditions.The tensile strength and fatigue strength of the AZ31B joints welded by laser/arc hybrid process are equivalent to that of the based metal.Besides,the laser-induced plume/plasma images captured by high speed camera were used to study the interaction between laser beam and arc.

Effect of laser power on metal transfer in laser-double arcs P-MAG hybrid welding with single power source

The effect of laser power on metal transfer is studied under conditions of alternating combustion of double arcs in order to develop the welding process of the laser-double arcs pulsed metal active gas （P-MAG） hybrid welding with single power. Different laser power corresponds to different interactive mechanisms of laser and arc and to different methods of metal transfer in the hybrid welding. When the laser power ascends from 500 W to 1 500 W, the methods of metal transfer change from the complex transfer of one droplet per pulse, one droplet two pulses and one droplet much more pulses during the mixture of globular and projected transfer of the lead wire, and from one droplet two pulses and one droplet three pulses during globular transfer of the follow wire to the methods of the metal transfer of both lead wire and follow wire are stable one droplet two pulses and one droplet three pulses when the metal transfer is mainly globular. The arc sharps and pressure of droplet are altered with the laser power changing. The compression of the arcs is strengthened by the laser and the offset of the center of droplet mass is much more obvious with the increasing of the laser power.

Numerical simulation of temperature field in laser-arc hybrid welding of wear-resistant steel

Using ABAQUS software and cylindrical ellipsoid and body heat sources with a peak-heat-flux- attenuation function, a finite element model of the temperature field in the laser-arc hybrid welding of 4.5-mm BW300TP wear-resistant steel is proposed. The proposed model considers convection, radiation, molten pool flow, and heat conduction effect on temperature. A comparison of the simulation and actual welding test results confirms the reliability of the model. This welding heat-process model can provide the cooling rate at any position in the heat affected zone （HAZ） and can be used as a reference for the analysis of material properties and for process optimization.

Novel hybrid method: pulse CO_2 laser-TIG hybrid welding by coordinated control

In continuous wave CO2 laser-TlG hybrid welding process, the laser energy is not fully utilized because of the absorption and defocusing by plasma in the arc space. Therefore, the optimal welding result can only be achieved in a limited energy range. In order to improve the welding performance further, a novel hybrid welding method--pulse CO2 laser-TIG arc hybrid welding by coordinated control is proposed and investigated. The experimental results indicate that, compared with continuous wave CO2 laser-TIG hybrid welding, the absorption and defocusing of laser energy by plasma are decreased further, and at the same time, the availability ratio of laser and arc energy can be increased when a coordinated frequency is controlled. As a result, the weld appearance is also improved as well as the weld depth is deepened. Furthermore, the effect of frequency and phase of pulse laser and TIG arc on the arc images and welding characteristics is also studied. However, the novel hybrid method has great potentials in the application of industrials from views of techniques and economy.

Experimental study on gas metal arc welding and laser hybrid welding of WYS700 steel

Gas metal arc welding, laser welding, and laser-metal active gas welding(MAG) hybrid welding methods were applied to WYS700 steel.Different welding procedures were performed and different welding technologies were compared.Macro metallographs of the welded joints were obtained, and the mechanical properties(such as tensile strength, bending property, and hardness) of the joints formed using the different welding technologies were determined.The results revealed that the joint of the WYS700 steel could be formed well through gas metal arc welding, laser welding, and laser-MAG hybrid welding.Furthermore, the softening of the welding heat affected zone can be effectively reduced to obtain good strength and plasticity by using a suitable welding procedure.Laser-MAG hybrid welding allows the realization of high efficiency and deep penetration for the welding of thick plates with specifications above 3 mm.

激光-电弧复合焊接铝合金的研究进展分析

为早日实现“双碳”目标,轻量化制造是必经之路。铝合金以其低密度、高比强度和可回收利用等优点脱颖而出,并且具备高塑形、优良耐腐蚀能力从而可以广泛应用于各行各业,但因为其特殊的热物理性质及复杂的合金化学成分,使其焊接过程中极易出现气孔、热裂纹等焊接缺陷,其焊接难题限制了铝合金在轻量化之路的进一步发展。激光-电弧复合焊接技术结合激光焊接技术与电弧焊接技术的优势,以其大焊接熔深、高焊接效率、高焊接质量著称,并逐渐成为铝合金高效优质焊接的重要熔焊工艺。为掌握铝合金激光-电弧复合焊的研究现状,本文首次通过文献计量学的方法定量分析了Web of Science(WoS)数据库中1995—2021年已发表的该领域的学术论文,并通过使用VOSviewer软件对WoS数据库数据进行了可视化处理。结果表明,焊接接头、微观组织、热影响区、力学性能及激光与电弧的相互作用为研究热点,因此本文从上述领域对铝合金的激光-电弧复合焊接进行了总结与分析,并结合激光-电弧复合焊接过程中的在线监测技术与新型激光在复合焊中的应用展开讨论分析,得出激光-电弧复合焊接铝合金中接头类型的选取,微观组织的分布,力学性能的提升措施及复合热源的相互作用机制。旨在为后续研究激光-电弧复合焊接铝合金提供参考。最后,基于当下的研究现状,本文提出了该领域面临的挑战及未来工作展望。

390MPa级船用高强钢激光-MAG复合焊接接头组织与力学性能

对8 mm厚390 MPa级船用高强钢进行了激光-MAG电弧复合焊接,研究了焊接接头焊缝形状和组织特征,分析了焊接接头硬度分布、拉伸性能和冲击性能。结果表明,激光-MAG复合焊接焊缝呈“酒杯”状,热影响区宽度较小。焊接速度为0.8 m/min时,焊缝区组织主要为先共析铁素体、侧板条铁素体、针状铁素体和板条贝氏体;焊接速度达到1.2 m/min以上时,先共析铁素体和侧板条铁素体比例显著减小,针状铁素体和板条贝氏体比例增加。焊接接头硬度均高于母材,没有明显软化区。激光-MAG复合焊接接头具有良好的低温冲击韧性;随着焊接速度增大,焊缝区-40℃和-60℃冲击吸收能量显著增加。

焊接位置对激光-电弧复合焊接底部驼峰的影响

目的通过改变焊接位置来抑制底部驼峰的形成进而降低生产成本。方法使用高速摄像机观察平向焊接和横向焊接2种不同焊接位置下熔池的匙孔和底部驼峰的形成过程,并对底部凸起受到的金属蒸气反冲压力、熔融金属重力以及表面张力进行受力分析。结果在S355J2W耐候钢的激光-电弧复合焊接平焊过程中,受金属蒸气反冲作用力的影响,熔融金属迅速从匙孔底部排出,流入匙孔底部凸起区域,底部凸起的增长速度极快,仅需7.5 ms即可形成大尺寸的驼峰。而在横向焊接中,匙孔前壁凸起数量减少,导致金属蒸气反冲压力减小,匙孔排出的熔融金属量减少,底部凸起的增速减缓,在13.6 ms时才达到最大高度,使驼峰在底部熔池凝固之前难以形成。结论采用横向焊接的方式可以有效避免驼峰的产生,降低生产成本。同时,该方式在焊缝背部成形效果方面也表现良好,为优化焊接工艺提供了重要参考。

Q690钢激光-MIG复合焊焊缝耐腐蚀性能研究

采用焊接效率较高的激光电弧复合焊对Q690钢中厚板(16 mm)进行焊接试验,分析不同激光功率下焊接接头的显微组织和晶粒尺寸的变化,及其开路电位、交流阻抗谱、极化曲线和腐蚀形貌,探讨激光功率对焊缝电化学腐蚀行为的影响规律。结果表明,激光-MIG复合焊焊缝的显微组织由大量针状铁素体和少量侧板条铁素体、粒状贝氏体组成,其中电弧区的针状铁素体、侧板条铁素体含量多于激光区,电弧区的晶粒尺寸比激光区略大;粗晶热影响区显微组织主要由板条马氏体组成。随着激光功率的增加,焊缝中粒状贝氏体含量减少,针状铁素体和侧板条铁素体含量增加。当激光功率从1.5 kW增至2.5 kW时,焊缝的开路电位上升,容抗弧半径增加,极化电阻变大,极化曲线有右移倾向,自腐蚀电流密度下降,耐腐蚀性能提高。但当激光功率增至3.0 kW时,由于组织过于粗大,耐腐蚀性能反而下降。激光功率为2.5 kW时,复合焊焊缝的耐腐蚀性能最佳。

Q345B钢激光-电弧复合焊接工艺性能研究

利用激光-电弧复合焊接方法,研究了6 mm厚Q345B板激光-电弧复合焊接成形的影响规律,并分析了该方式下工况适应性及接头性能。结果表明:在激光功率为4000 W、焊接速度0.8 m/min、送丝速度8 m/min及光丝间距5 mm时获得了良好的焊缝成形,且对间隙和错边的适应性较好;焊缝X射线探伤可以达到I级合格;接头力学性能表现良好。

激光-电弧复合焊接技术及工艺认可

为突破激光焊接工艺的局限性,对激光-电弧复合焊接技术的工作原理和工艺特点进行介绍,并对试验过程中常见的焊接缺陷和原因进行分析汇总,在此基础上,给出激光-电弧复合焊接工艺认可提示和规范完善建议。研究成果可为激光-电弧复合焊接技术在船舶制造业中的应用提供一定参考。

铝合金高频振荡扫描激光-电弧复合焊缝成形规律与预测

高频振荡扫描激光-电弧复合焊接能够通过扫描搅拌效应调控铝合金焊缝微观组织及其力学性能,但是在控形方面还鲜有研究,无法为工业应用提供理论支撑.为此,系统研究了激光束扫描振幅A和频率f对AA6082铝合金激光-电弧复合焊缝成形特征的影响规律,包括焊缝表面飞溅、焊缝下部激光区宽度和熔深占比,并基于光束扫描的能量分布特征和激光焊接模式转变行为,探讨了焊缝形貌转变机理.随后,根据焊缝成形缺陷数量和激光深熔焊模式进一步确定了激光束扫描参数的优化区间范围,具体为0.4 mm≤A≤1.0 mm和300 Hz≤f≤500 Hz.最后,通过对光束扫描参量的线速度归一化处理,建立了优化参数区间内的焊缝特征值的线性定量关系,精度达到89.8%,为高频振荡扫描激光-电弧复合焊缝形貌特征的预测与调控提供了数据支撑.

Q345E钢激光-电弧复合焊T形接头疲劳性能

为探究激光-电弧复合焊接技术在转向架结构中应用的可能性,以20 mm厚的Q345E钢T形接头为研究对象,开展了激光-电弧复合焊接试验,并采用单点法和升降法进行疲劳性能测试.结果表明,当指定循环次数为5×10^(6)时,复合焊接头的中值疲劳强度为148.3 MPa,循环2×10^(6)时的条件疲劳强度为181.5 MPa,比相应的电弧焊接头提高39.6%,且焊接组织更细小,提高了裂纹萌生过程中所需的疲劳循环次数.疲劳裂纹形貌特征表明,T形接头的疲劳裂纹起源于封底焊缝焊趾处,瞬断区为韧性断裂模式,复合焊接头疲劳性能提高的原因在于其封底焊缝焊趾处具有较小的应力集中系数,且焊缝微观组织由更为细小的晶内铁素体组成,能够有效避免疲劳裂纹过早萌生,并阻碍疲劳裂纹扩展.

Challenge to Welding and Joining Technology for Applying Multi-material in Electric Vehicle Production

Advanced high strength steel,aluminum alloy and plastic materials are used in the right places for the purpose of reducing the weight of EV(electric vehicle)bodies and in-vehicle parts,and multi-material structures are advancing.Therefore,it is difficult to handle the welding and joining processes of automobile structures by the conventional arc welding and resistance spot welding,which have been applied to steel joining,and various joining processes are being applied depending on the material.Under above mentioned background,the authors have developed some unique joining processes for multi-materials that are used in the right place.This paper introduces the dissimilar metal joining between the galvanized steel and aluminum alloy by laser arc hybrid process,the metal/thermoplastic dissimilar material joining using laser process and the solid-state resistance spot joining process of advanced high strength steel for EV body structural parts.Moreover,the authors describe the high-speed plasma jet GTA(Gas Tungusten Arc)welding process of copper applied to electrical components such as motors.

船用11mm厚AH36钢激光-电弧复合焊接工艺研究

采用激光-电弧复合焊接方法,以ER70S-6焊丝为填充材料,对船用11mm厚AH36钢进行焊接。分析焊接速度、激光功率及送丝速度对焊缝成形的影响,得出合适的焊接参数,并通过对焊接接头进行无损检测,以及拉伸、弯曲、宏观、冲击和硬度试验,研究了焊接接头力学性能。结果表明:在确定的焊接参数下,船用11mm厚AH36钢激光-电弧复合焊接焊缝正反面成形好,抗拉强度为520MPa,断裂于母材位置,焊缝与母材熔合良好,接头焊缝、熔合线、熔合线+2mm、熔合线+5mm位置平均冲击吸收能量为101~221J,接头母材、热影响区、熔合线及焊缝硬度为155~342HV,满足ISO相关标准和中国船级社规范要求。

中厚板激光-电弧复合焊拼板坡口的选用

研究了船用中厚板采用激光-电弧复合焊拼板时,焊接坡口的选择方法。对20mm厚EH36船用钢进行焊接,对比Y形、带钝边的U形、带钝边的复合坡口3种形式的激光-电弧复合焊缝成形,以及不同钝边高度和坡口角度激光-电弧复合焊焊缝成形的差异。分析不同坡口对激光-电弧复合焊焊缝成形、坡口制备难易度、焊接层数的影响。结果表明:采用Y形、带钝边的U形、带钝边的复合坡口这3种形式进行激光-电弧复合焊,均可得到较好的激光-电弧复合焊焊缝成形。考虑坡口形式对坡口制备的难易度、对焊接层数的影响,得出Y形坡口最优。当钝边高度值相同时,若一定程度上增大坡口角度,则利于激光-电弧复合焊焊缝正面的成形。当坡口角度相同时,一定程度上降低钝边高度,利于激光-电弧复合焊焊缝反面的成形。

Hybrid laser/arc welding of thick high-strength steel in different configurations

In this investigation, hybrid laser/arc welding （HLAW） was employed to join 8-mm-thick high-strength quenched and tempered steel （HSQTS） plates in the butt- and T-joint configurations. The influences of welding parame- ters, such as laser power, welding speed, stand-off distance （SD） between the arc of gas metal arc welding, and the laser heat source on the weld quality and mechanical properties of joints, were studied to obtain non-porous and crack-free fully-penetrated welds. The weld microstructure, cross- section, and mechanical properties were evaluated by an optical microscope, and microhardness and tensile tests. In addition, a finite element model was developed to investigate the thermal history and molten pool geometry of the HLAW process to join the HSQTS. The numerical study demon- strated that the SD had a paramount role in good synergy between the heat sources and the stability of the keyhole. For the butt-joint configuration, the results showed that, at a higher welding speed （35 mm/s） and optimum SD between the arc and laser, a fully-penetrated sound weld could be achieved. A non-porous weld in the T-joint configuration was obtained at a lower welding speed （10 mm/s）. Microstructural evaluations indicated that the formation of residual austenite and the continuous network of martensitic structure along the grain boundary through the heat affected zone were the primary reasons of the softening behavior of this area. This was confirmed by the sharp hardness reduction and failure behavior of the tensile coupons in this area.

X80/X100异种钢激光-MIG复合焊接头显微组织和性能

采用激光-MIG复合焊对X80管线钢和X100管线钢进行焊接,研究了激光功率对复合焊接头的焊缝形貌、显微组织、硬度、强度和韧性的影响规律.结果表明,激光功率从2.0 k W增大至3.5 k W时,盖面焊缝熔宽和熔深增加,激光区熔深明显增加;激光区焊缝中AF含量增加、LB含量减少,X100侧粗晶热影响区和细晶热影响区中条状贝氏体含量减少,X80侧粗晶热影响区和细晶热影响区中准多边形铁素体含量增加.复合焊接头硬度分布并不对称,最高硬度出现在X100侧熔合区部位.复合焊接头的抗拉强度基本不随激光功率变化,拉伸试样断裂位置均为X80侧母材.随着激光功率增大,焊接接头最高硬度和韧性均下降.