2219高强铝合金活性TIG焊工艺

采用单组分活性剂(AlF_3和LiF)、3组分(AlF_3+30%LiF+10%KF-AlF_3)和4组分(AlF_3+30%LiF+10%KFAlF_3+10%K_2SiF_6)混合组分活性剂进行2219高强铝合金直流正极性活性TIG焊(DCSP A-TIG),研究4种类型活性剂对焊缝表面成型、焊缝内部质量(气孔)、焊缝熔深、电弧形态、接头组织与力学性能的影响。结果表明:涂覆活性剂有助于去除2219铝合金表面的氧化膜,提高焊缝表面成型质量,涂覆4组分活性剂的DCSP A-TIG焊缝表面成型质量最佳;与变极性TIG焊(VPTIG)焊缝内部质量相比,DCSP A-TIG焊接方法可显著降低2219铝合金焊缝内部气孔的产生;AlF_3单组分活性剂可显著增大焊缝熔深,其电弧形态具有明显的拖弧现象;DCSP A-TIG焊焊缝组织具有与母材相同的组织组成物,电流对A-TIG焊缝组织影响较大,增大焊接电流,会造成接头晶粒组织粗大;涂覆4组分活性剂的DCSP A-TIG接头强度和伸长率最高,与VPTIG焊接头力学性能具有相近的技术指标。2219高强铝合金的DCSP A-TIG焊接方法具有很大的工程应用价值。     

A-TIG焊研究进展及前景展望

对活性化钨极氩弧焊(A-TIG)焊接工艺、活性剂的研发及其在增加焊缝熔深机理等方面的研究做了比较详尽的综述,并指出活性化TIG焊研究过程中存在的问题、发展前景及今后研究方向。认为对活性焊剂增加熔深的机理还有待深入研究,可以利用数值模拟过程结合活性化TIG焊试验深入研究活性焊剂增加焊缝熔深的机理。可以基于A-TIG焊基本思想结合其他方法研发新的活性焊方法。总之,A-TIG焊具有巨大的发展潜力和良好的应用前景。     

粉煤灰/二氧化硅活性剂在Q235钢A-TIG焊中的应用

为了探究粉煤灰作为A-TIG焊活性剂的可行性,以粉煤灰和不同含量的二氧化硅制备复合活性剂在Q235钢基体表面进行A-TIG焊,研究了复合活性剂成分含量对焊缝截面形貌、显微组织和元素分布的影响.结果表明:采用粉煤灰-40%SiO_2作为复合活性剂进行A-TIG焊时,可将6 mm厚Q235钢板一次性焊透,焊缝深宽比可达到0.85;焊缝出现明显的中间收缩倾向,呈"深口杯"状,可实现单道焊双面成型的效果;其焊缝柱状晶数目较多、组织排列规则且具有方向性,熔合区和热影响区组织均匀细小,可降低焊接母材的过热倾向;相对于100%SiO_2活性剂,Si元素的溶入量和溶入深度显著增加,这说明粉煤灰中其他成分的存在对Si元素溶入焊缝、进而增加焊缝熔深起到促进作用.采用粉煤灰-40%SiO_2为活性剂进行A-TIG焊时焊缝熔深的增加机理可能是以电弧收缩理论为主,但考虑到Al元素溶入较深且溶入量较多,粉煤灰中其他物相又十分复杂,在高温电弧作用下各物相之间相互反应放热致使电弧热输入增加、其他组分在熔池中改变了熔池表面张力温度梯度等均可能致使焊缝熔深增加.     

有色合金A-TIG焊研究现状

活性化TIG焊(A-TIG焊)可以用于焊接不锈钢、碳钢、铝合金、镁合金、钛合金和镍基合金等材料。根据国内外关于A-TIG焊接技术研究、发展及应用的实际情况,综合论述了A-TIG焊接技术这一新型焊接方法在铝合金、镁合金、钛合金和镍基合金焊接领域中的研究现状。     

热力管道裂纹高效修复工艺研究

针对热力管道开裂问题频发现象,通过搭建与实际工况相似的试验平台,利用A-TIG焊(Activating flux TIG welding)对热力管道裂纹进行了修复.研制的纯氧化物低碳钢活性剂可以将8 mm厚的Q235试板焊透.修复试验结果表明:在管道无积液情况下,利用A-TIG焊可以修复6mm壁厚的管道裂纹,调整工艺参数可以修复更大壁厚的管道裂纹,在管道有积液情况下,配合手工焊进行密封焊接,然后进行A-TIG焊可以修复6 mm壁厚的管道裂纹,提高了热力管道裂纹修复的效率和质量.     

奥氏体不锈钢A-TIG焊工艺研究

目的研究焊接参数对焊缝成形和接头宏观组织的影响。方法改变焊接电流、焊接速度、焊接电压以及活性剂中的一个参数,固定其他3个参数不变,对奥氏体不锈钢进行焊接,分析其接头宏观形貌、组织和力学性能。结果随着电流、电压的增加,焊接接头的熔深和熔宽都在增加,随着焊接速度的增加,焊接接头的熔深和熔宽都在降低,在相同参数下,将不同活性剂下的A-TIG焊接头的熔深和熔宽进行比较,发现涂敷C4活性剂接头熔深最大达到4.29mm,而常规TIG焊接头熔深为1.38mm,涂敷C4活性剂的接头熔深为TIG焊的3.11倍,且熔宽也有所减小。结论 C4活性剂A-TIG最佳工艺参数为:I=175 A,U=14 V,v=80 mm/min,此时能将6 mm板材焊透,成形良好,在此工艺下焊缝等轴晶范围最大,焊缝组织最为细小。相比于TIG焊,涂敷C4活性剂接头强度系数提升4.1%。     

粉煤灰复合活性剂在A-TIG焊中增加熔深的机理研究

为实现对工业废弃物粉煤灰的剩余价值利用,尝试以粉煤灰作为主要原料制备焊接复合活性剂,并在AZ91镁合金板上进行A-TIG焊.利用焊缝的电特性实时采集、焊接温度场采集、电弧力测试等手段研究活性剂对电弧影响,通过熔池Bi粒子示踪实验探究活性剂对表面张力温度梯度影响.结果 表明:与常规TIG焊相比,粉煤灰复合活性剂可以使焊缝熔深增深1.4倍,熔宽减小,深宽比是常规TIG焊的1.43倍.粉煤灰复合活性剂中氟化物的解离和电离吸热过程、带电粒子的电子扩散和复合过程可以促进电弧收缩,使焊接电压升高,热输入量提高.而活性剂中的氧化物既可以通过对电弧的机械压缩作用强迫电弧收缩,又可以通过电离产生的氧元素实现对熔池液态金属表面张力温度梯度系数的改变,提高熔池中心热输入.A-TIG焊AZ91镁合金熔深增加是电弧收缩理论和表面张力温度梯度改变理论共同作用的结果.     

活性剂增加不锈钢A-TIG焊熔深机理研究

目的研究涂敷活性剂条件下1Cr18Ni9Ti奥氏体不锈钢的熔深增加机理。方法采用B1活性剂,涂敷在1Cr18Ni9Ti奥氏体不锈钢表面,进行A-TIG焊试验,分析活性剂对电弧形貌、阳极斑点、电弧电压和焊缝熔深的影响情况。结果涂敷活性剂后,电弧和阳极斑点都发生了收缩,电弧宽度由4.97 mm变为4.12mm,减小了17.1%,阳极斑点长轴长度由9.92 mm变为8.22 mm,短轴长度由4.75 mm变为4.35 mm,电弧电压提高了2.7 V,阳极区和弧柱区收缩,提高了弧柱电场强度;相同参数下,涂敷活性剂后熔宽缩小0.62mm,熔深增加了3.01 mm,显著增加熔深。结论阳极斑点收缩和电弧收缩是活性剂增加不锈钢A-TIG焊熔深的主要原因。     

活性剂涂敷量对A-TIG焊熔深影响的研究

常规TIG焊生产效率低，单道焊可焊厚度小，活性化TIG焊（A-TIG），同常规TIG焊相比可大幅度地提高焊缝熔深，从而提高焊接效率，针对不锈钢材料，通过宏观断面分析方法研究了单一成分的活性剂（SiO2,CaF2,TiO2,Cr2O3和NaF)对焊缝熔深的影响，结果表明：同常规TIG焊相比，上述5种活性剂在涂敷量较小时，焊缝熔深均随活性剂涂敷量的增加而明显增大，氧化物活性剂增加熔深的作用效果大，氟化物的作用效果较小；5种活性剂在熔深增加能力上均有一个饱和点；电弧收缩和熔池表面张力梯度的变化是活性剂增加熔深的主要原因。     

快速凝固耐热铝合金焊接技术的研究现状

阐述了快速凝固耐热铝合金焊接研究现状,分析了快速凝固耐热铝合金的焊接性,讨论了钨极氩弧焊、电容放电焊、电子束焊、激光焊、摩擦焊以及钎焊在快速凝固耐热铝合金材料连接中的应用和存在的问题,指出具有高能量密度、低能量输入的电子束焊、激光焊以及摩擦焊适于快速凝固耐热铝合金的焊接.     

活性剂对CO2气体保护焊焊缝成形及飞溅的影响

使用自制的活性焊丝,研究了活性剂对CO2气体保护焊焊缝成形及飞溅的影响。结果表明,使用活性剂可以使焊接飞溅率大大降低,焊缝熔深增加,熔宽增大,焊缝表面成形光滑。认为CO2气体保护焊飞溅降低的原因,是因为活性剂的加入在降低了混合气体的有效电离电压的同时显著增加了CO2电弧的导电能力,使电弧能量密度增加,从而使中等电流下的熔滴过渡方式由大颗粒过渡转变成细颗粒过渡。     

Research on the Mechanism of Penetration Increase by Flux in A-TIG Welding

The mechanism of penetration depth increased by activating flux in activating tungsten inert gas (A-TIG) weldingwas studied by measuring the distribution of trace element Bi in the weld and monitoring the change of arc voltageduring A-TIG welding of stain     

粉末熔池耦合活性TIG焊接方法

提出了一种新型活性焊接方法——粉末熔池耦合活性TIG焊(Powder pool coupled activating TIG welding,PPCATIG)。该方法采用双层气体进行焊接,内层利用惰性气体保护钨极,外层通过自动送粉装置将活性剂粉末随保护气体送入电弧-熔池区域,增加熔深,提高焊接效率,实现机械化自动化焊接。针对SUS304不锈钢进行了直流正接PPCA-TIG表面熔深,通过与传统TIG焊对比,研究了SiO_2活性剂对电弧形态、焊缝成形、组织和力学性能的影响。结果表明:SiO_2能使电弧等离子体收缩、熔池金属流态改变,并且焊缝熔深能达到传统TIG焊的3倍以上,焊接效率明显提高。焊缝组织主要为奥氏体和铁素体,铁素体形态以骨架状为主。焊缝抗拉强度略低于母材,但相比传统TIG焊,焊缝屈服强度略有提高,其焊缝低温冲击韧性达到了传统TIG焊的96.8%,表现出了良好的力学性能。同时,采用该方法可有效避免活性剂粉末对钨极的污染。     

低碳钢氩弧焊焊剂的研制

针对低碳钢研制了由卤化物、SiO2 ,TiO2 ,Cr2 O3 等组成的氩弧焊焊剂 ,分析了各种单一成份的活性剂对焊接熔深的影响规律。在此基础上对多组元活性剂进行研究 ,优选出合适的配方 ,按此配方制成的活性剂可以大幅度地增加低碳钢氩弧焊的熔深 ,可一次焊透 12mm厚的对接低碳钢钢板     

Effects of activating flux on the welded joint characteristics in gas metal arc welding

This paper presents the effect of each welding parameter on the weld bead geometry, and then sets out to determine the optimal process parameters using the Taguchi method to determine the parameters. Three kinds of oxides, Fe₂O₃, SiO₂, and MgCO₃, were used to investigate the effect of activating flux aided gas metal arc welding (GMAW) on weld bead geometry, angular distortion and mechanical properties in AISI 1020 carbon steel. During welding, a charge coupled device (CCD) camera system was used to observe and record images of the welding arc and analyze the relationship between penetration increase and arc profile. The experimental results showed that activating flux aided GMAW increased the weld area and penetration and tended to reduce the angular distortion of the weldment. The MgCO₃ flux produced the most noticeable effect. Furthermore, the welded joint presented better tensile strength and hardness.     

不锈钢高效氩弧焊焊剂的研制

针对 30 4不锈钢的焊接研制了一种A TIG焊活性剂。该活性剂由B2 O3、MnO、Fe2 O3、Al2 O3、SiO2 、TiO2 、Cr2 O3、NaF等组成。分析了各单一活性剂对焊接熔深的影响规律 ,在此基础上结合 30 4不锈钢的合金元素系统 ,初步确定了活性剂的基本成分。利用正交试验得出了各组元含量变化对焊接熔深的影响规律 ,所得到的配方可使焊接熔深增加 2倍多 ,可将 8mm厚不锈钢钢板直边坡口对接一次焊透。焊接接头的金相组织 ,焊缝的化学成分 ,焊接接头的力学性能和抗晶间腐蚀性能均能满足相关的要求     

The mechanism of penetration increase in A-TIG welding

The mechanism of the increasing of A-TIG welding penetration is studied by using the activating flux we developed for stainless steel. The effect of flux on the flow and temperature fields of weld pool is simulated by the PHOENICS software. It shows that without flux, the fluid flow will be outward along the surface of the weld pool and then down, resulting in a flatter weld pool shape. With the flux, the oxygen, which changes the temperature dependence of surface tension grads from a negative value to a positive value, can cause significant changes on the weld penetration. Fluid flow will be inward along the surface of the weld pool toward the center and then down. This fluid flow pattern efficiently transfers heat to the weld root and produces a relatively deep and narrow weld. This change is the main cause of penetration increase. Moreover, arc construction can cause the weld width to become narrower and the penetration to become deeper, but this is not the main cause of penetration increase. The effects of flux on fluid flow of the weld pool surface and arc profiles were observed in conventional TIG welding and in A-TIG welding by using high-speed video camera. The fluid flow behavior was visualized in real-time scale by micro focused X-ray transmission video observation system. The result indicated that stronger inward fluid flow patterns leading to weld beads with narrower width and deeper penetration could be apparently identified in the case of A-TIG welding. The flux could change the direction of fluid flow in welding pool. It has a good agreement with the simulation results.     

Effects of the Process Parameters on Austenitic Stainless Steel by TIG-Flux Welding

The effects of the process parameters of TIG （tungsten inset gas）-flux welding on the welds morphology, angular distortion, ferrite content and hot cracking in austenitic stainless steel were investigated. Autogenous TIG welding process was applied to the type 304 stainless steel through a thin layer of activating flux to produce a bead on plate welded joint. TiO2, SiO2, Fe2O3, Cr2O3, ZnO and MnO2 were used as the activating fluxes. The experimental results indicated that the TIG-flux welding can increase the weld depth/width ratio and reduce the HAZ （heat affected zone） range, and therefore the angular distortion of the weldment can be reduced. It was also found that the retained ferrite content within the TIG-flux welds is increased, and has a beneficial effect in reducing hot cracking tendency for stainless steels of the austenitic type weld metals. A plasma column constriction increases the current density at the anode spot and then a substantial increase in penetration of the TIG-flux welds can be obtained.     

AC TIG welding with single-component oxide activating flux for AZ31B magnesium alloys

Magnesium-based alloys are finding extensive applications foreground in aerospace and automotive applications. Weldability of magnesium alloys has recently been investigated with a variety of processes. In this article, the activating flux TIG (ATIG) welding of magnesium alloys with three single-component fluxes (TiO₂, Cr₂O₃ and SiO₂) under alternating current (AC) mode was studied. The effects of welding speed, weld current and electrode gap on the weld shape and the weld arc voltage in AC TIG welding with oxide fluxes were investigated on an AZ31B magnesium alloy substrate. The mechanisms of oxide fluxes on the arc shape and the arc voltage on the weld shape are discussed. The result showed that the TiO₂ and Cr₂O₃ increase the weld penetration of AC TIG welding of magnesium with good bead cosmetics. The SiO₂ increased the weld penetration with very poor formation of the weld surface. However, the arc voltage decreased with the used of TiO₂ flux, and increased with the used of Cr₂O₃ flux. The mechanism of TiO₂ and Cr₂O₃ fluxes increasing penetration should not accord with the “arc constriction”. It would comply with some potential effects of the flux interacting with the liquid metal of fusion zone.