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高频微振条件下激光焊接组织研究 总被引:2,自引:0,他引:2
为了研究振动工艺在激光焊接方面的应用,选用工业纯铁为研究对象,进行不同激光焊接参数与振动频率下的高频微振光纤激光焊接,达到优化接头成形,提高焊接质量的目的。利用超景深显微镜观察焊接接头宏观形貌,利用扫描电镜分析接头微观组织,利用显微硬度计测量焊接接头显微硬度分布。结果表明:在高频微振激光焊接中,施加振动可增加焊接接头熔深。焊缝晶粒细化,表现为振动频率越快,晶粒越细小。振动加速度可以作为振幅的替代参量;当振动频率与材料本身固有振动频率相近时,振动加速度越大,晶粒细化作用不明显。当激光功率为3 000 W、离焦量为-10 mm、焊接速度为1.2 m/min、振动频率为118 Hz、振动加速度为36.1 m/s~2时,焊接接头的整体平均显微硬度由无振动条件下的273.3 HV降低到244.6 HV,且组织晶粒细化最明显。 相似文献
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对一种新型α+β双相镁锂合金的搅拌摩擦焊及电子束焊进行了实验研究,为该合金在精密制造领域的应用提供参考。利用金相显微镜、扫描电镜和显微硬度测试探明接头显微组织和力学性能的演变规律和特点。结果表明,在合理的工艺参数下,镁锂合金搅拌摩擦焊接头焊核区α+β双相都得到了明显的细化,演变为等轴晶,且α相体积分数相对减少。在焊接速度为15 mm/s,聚焦电流为500 ~ 540 mA,焊接电流为8~10 mA时,5 mm厚镁锂合金电子束焊焊缝完全焊透,焊缝区域由细小的等轴晶组织组成,α相分布更加弥散,呈网状分布在β晶界上。两种工艺下焊缝区显微硬度(HV)较母材均提升了13左右。综上,采用搅拌摩擦焊及电子束焊均可实现外观成型、组织以及性能优良的镁锂合金连接。 相似文献
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不同冷却条件下激光焊接接头性能研究 总被引:1,自引:0,他引:1
分别利用焊后空冷和随焊水冷两种随焊冷却方式对2 mm厚低碳钢板进行光纤激光焊接。选择不同激光功率、焊接速度和离焦量进行试验。分析焊后空冷条件下和随焊水冷条件下两种焊接接头成形、金相组织和显微硬度。研究结果表明,随焊水冷条件下的焊缝宽度和热影响区宽度分别小于焊后空冷条件下的焊缝宽度和热影响区宽度;在热输入相等和正离焦的前提下,熔宽随着离焦量的减小而增大。两种冷却条件下的焊缝组织为板条状先共析铁素体和珠光体。随焊水冷条件下热影响区晶粒尺寸较焊后空冷下的晶粒有明显细化。空冷条件下焊缝中柱状晶的生长方向与焊缝中心线成70°~80°,而随焊水冷条件下的柱状晶生长方向几乎与焊缝中心线垂直。焊后空冷和随焊水冷的焊缝区域平均硬度分别为316.7 HV0.2和331.5 HV0.2,均高于母材硬度平均值181.8 HV0.2;同时,随焊水冷条件下焊缝硬度稍高于焊后空冷条件下的焊缝硬度。 相似文献
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高强钢厚板激光-GMAW复合双面同步横焊特性研究 总被引:3,自引:0,他引:3
针对30 mm厚船用高强钢10Ni5Cr Mo V对接接头横焊应用需求,开展激光-熔化极气体保护电弧(Gas metal arc welding,GMAW)复合双面同步横焊特性研究。研究结果表明,针对横焊位姿因重力、非对称坡口对熔滴、电弧的影响,利用激光对电弧的吸引和收缩作用,通过减小光-丝间距,有效地抑制了电弧侧壁燃弧,熔滴在电磁力和等离子流力的作用下,稳定过渡到熔池中,实现了熔滴过渡稳定性控制,解决了激光-GMAW复合横焊位姿电弧偏离和熔滴下落等过程控制难题与侧壁未熔合问题;厚板激光-GMAW复合双面同步横焊包括打底层和填充层焊接,其中打底层焊接是保证接头焊接质量的关键;采用激光-GMAW复合双面同步横焊新方法,4道焊接完成了30 mm厚船用高强钢10Ni5Cr Mo V横焊位姿的高强、高效连接。焊缝表面成形良好,无裂纹、未焊透和侧壁未熔合等缺陷。接头的抗拉强度高于母材,且其–50℃冲击吸收能量为57.3 J。 相似文献
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对TC4钛合金单面修饰激光焊接接头进行激光冲击强化,对比强化前后焊接接头的疲劳寿命,在光学显微镜和扫描电镜下观察断口疲劳断裂特征,并从焊接接头的显微硬度、微观组织、残余应力分布等方面综合分析激光冲击强化对TC4钛合金单面修饰激光焊接接头的强化机理。试验结果表明:未强化和强化试样均在焊缝咬边处萌生疲劳裂纹,强化试样疲劳寿命是未强化试样疲劳寿命的3.77~9.15倍,强化试样焊缝咬边处马氏体细化,显微硬度提高,焊缝表面呈残余压应力分布,焊缝咬边处残余压应力达-564.37±9.85MPa。晶粒细化和高幅值残余压应力综合作用下抑制了焊缝咬边处疲劳裂纹的萌生,且增大了裂纹扩展阻力,从而提高了焊接接头疲劳性能。 相似文献
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采用激光器YLS-10000型光纤激光器进行试验焊接5mm厚的TC_4钛合金,研究不同热输入变化对焊接接头形貌以,微观显微组织、显微硬度的影响。试验结果表明:TC_4钛合金焊缝具有三种截面形貌,分别为漏斗形和酒杯形、双曲线形,在热输入超过72J/mm后,能够将焊缝充分焊透。热输入不一样,焊接组织具有一致性,焊缝组织为针状马氏体α′,没有发现新相,热影响区硬度发生突变具有软化区。原因是冷却期间焊缝区将存在α′,焊缝区α′比热影响区的数量要多,故接头硬度值先降低后升高,不同热输入下焊接接头整体硬度高于母材,随着热输入的增加焊缝的平均硬度增加且软化区向母材移动。 相似文献
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铝合金尤其是热处理强化铝合金焊后不可避免会出现热影响区软化现象,导致焊接接头的力学性能显著下降。基于热导拘束+局部变形强化构想,提出一种铝合金焊轧复合成形方法,系统分析铜垫强制冷却非熔化极惰性气体保护电弧焊(Tungsten inert gas, TIG)填丝对接焊及焊后轧制复合工艺对5083-O和6061-T6异种铝合金焊接接头组织和力学性能的影响。结果表明,采用焊轧复合成形方法,能够得到成形良好且无缺陷的铝合金对接接头,通过轧制使焊接接头同时发生了纵向变形和横向变形;焊后轧制可以压实铝合金焊缝组织,有效降低焊接接头部分熔化区的宽度,同时热影响区(包括固溶区和过时效软化区)晶粒发生位向改变甚至转动现象;与自由冷却焊接工艺相比,采用铜垫冷却的焊接接头6061-T6侧软化区硬度升高且向焊缝中心产生明显偏移,焊后轧制使两种冷却方式的焊接接头的整体硬度均得到大幅度提升,其中软化最严重位置硬度值由59.5HV提高到84.4HV,提升幅度为41.8%;两种冷却方式的焊接接头轧制后接头的抗拉强度均大幅度提升,其中铜垫冷却焊轧复合成形与自由冷却焊接接头相比,试样抗拉强度由197.0MPa提升到288... 相似文献
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为提高45钢的综合力学性能,利用CO2激光器对其表面进行激光熔凝处理,分析了熔凝层的微观组织和显微硬度。结果表明,熔凝层质量优良,晶粒较基体明显细化,显微硬度较基体显著提高,平均硬度为700HV,最高达750HV,约是基体硬度的3倍。 相似文献
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Evaluation on microstructure and mechanical properties of high-strength low-alloy steel joints with oscillating arc narrow gap GMA welding 总被引:1,自引:0,他引:1
W. H. Xu S. B. Lin C. L. Fan C. L. Yang 《The International Journal of Advanced Manufacturing Technology》2014,75(9-12):1439-1446
Abstract with the purpose of improving weld joint quality and productivity, the oscillating arc narrow gap gas metal arc (GMA) welding was employed in welding quenched and tempered high-strength low-alloy thick steel. The microstructure and mechanical properties of weld joints were evaluated, namely micro-hardness, tensile strength, and low-temperature impact toughness. The test results indicated that mechanical properties of weld joints with oscillating arc narrow gap GMA welding were excellent and found to meet stipulated requirements. Oscillating arc narrow gap GMA welding is a promising process for welding quenched and tempered HSLA thick steels due to the low energy input and narrow square-butt groove. 相似文献
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通过对LY12CZ铝合金填充LY12和A1-Y焊粉激光搭接焊缝的金相组织分析、显微硬度测试,研究如何有效控制JHM-1GX-200B型YAG脉冲式激光器搭焊LY12CZ铝合金的有关工艺参数,从而使焊缝达到较好的性能。研究结果表明,填充LY12和A1-Y两种不同的粉末对LY12材料进行搭焊处理,粉末和基体均结合牢固,但LY12粉焊缝的硬度总体高于A1-Y粉焊缝的硬度。由于焊缝靠近基体位置有退火过程,强化相析出聚集长大,强化作用下降,其显微硬度分布规律由基体向焊缝中心过渡呈现下降的趋势。同时由于焊缝内部气孔、裂纹的缺陷较多,造成焊缝各点硬度分布不均匀,且相差较大。 相似文献
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Xiaoyu Cai Huan Li Huiliang Wei Lijun Yang Ying Gao 《The International Journal of Advanced Manufacturing Technology》2014,75(9-12):1829-1836
In this paper, the effect of laser on the welding process in metal inert gas (MIG) welding of aluminum alloys was studied exploiting high-speed imaging and welding electrical signals collecting. Bead-on-plate welding experiments were conducted using conventional short-circuiting transfer MIG welding and laser-short-circuiting transfer MIG hybrid welding. The obtained results point out that it took less time to strike the arc in laser-MIG hybrid welding, and the stability of arc striking was increased. When the laser was introduced into the arc atmosphere, the arc was compressed, and the welding energy was more concentrated. The arc cathode spot was fixed to the laser beam impinging spot, so the arc could burn stably. In laser-MIG hybrid welding, the droplet short-circuiting transfer stability and the weld appearance were improved significantly. Moreover, an analysis method of judging droplet transfer stability which bases on statistical techniques was proposed. By this method, it can be concluded that the short-circuiting transfer process became more stable in laser-MIG hybrid welding. 相似文献
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通过室温拉伸和硬度及分析等方式,对Q450NQR1耐候钢混合气体保护焊焊接接头的力学性能进行了研究,试验结果表明:CHW-55CNH实芯焊丝焊接时,可以获得拉伸性能均良好的焊接接头,焊缝区硬度较均匀,焊缝的硬度在170~220 HV之间。 相似文献
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The effects of welding processes on abrasive wear resistance for hardfacing deposits 总被引:1,自引:0,他引:1
In this research, four kinds of welding deposits were evaluated, applied through two different welding processes: flux cored arc welding (FCAW) and shielded metal arc welding (SMAW). The other variable of the tests was the deposited layers. The hardfacing deposits were evaluated using the dry sand-rubber wheel machine according to procedure A of the ASTM G65 standard. Optical and scanning electron microscopy was used for the characterization of the microstructure and worn surface of deposits. FCAW welds presented higher abrasive wear resistance than the SMAW deposits. The hardfacing deposit formed by uniformly distributed carbides rich in titanium presented the highest abrasive wear resistance. Abrasive wear resistance was higher when three layers were applied, except for SMAW-D deposit. It was not possible to get a clear relation between hardness and the abrasive wear resistance of the deposits. The results showed that the most important variable to improve abrasion resistance is the microstructure of hardfacing deposits, where the carbides act as barriers to abrasive particle cutting. 相似文献
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Effects on mechanical properties in electron beam welding of TC4 alloy by laser shock processing 总被引:1,自引:0,他引:1
Lu Jinzhong Zhang Yongkang Kong Dejun Ren Xudong Ge Tao Zou Shikun 《Frontiers of Mechanical Engineering in China》2007,2(4):478-482
The surface of TC4 titanium alloy welding line by electron beam welding (EBW) was processed by high power Q-switched and repetition-rate
Nd: glass laser. Effects of laser power and spot diameter on residual stress and microhardness of the TC4 alloy welding line
by laser shock processing (LSP) have been analyzed. Results show that residual stresses almost do not change as laser power
is 45.9 J, spot diameter is ϕ9 mm; While laser power is 45.9 J, spot diameter less than ϕ3 mm, the distribution of residual
stress in welding line occurs obvious variation, which residual stress increase obviously with spot diameter decrease. When
power density is bigger than 1.8 × 1010 W/cm2, residual stresses of electron beam welding line occur change by LSP, which improve obviously residual stress distribution;
while laser power is bigger than 1.2 × 1010 W/cm2, the surface micro-hardness of electron beam welding line occurs change by LSP, which improve obviously micro-hardness distribution.
Mechanical properties of TC4 titanium alloy welding line will be improved by LSP, which provides experimental foundation for
further controlling the distributions of residual stress and micro-hardness during laser shock processing.
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Translated from Journal of Jiangsu University (Natural Science), 2006, 27(3): 207–210 [译自: 江苏大学学报 (自然科学版)] 相似文献