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通过高速摄影技术及焊接飞溅率测试试验,详细阐述了金属粉型高铬铸铁自保护硬面药芯焊丝的熔滴过渡过程以及飞溅产生的原因及特点。结果表明,高铬铸铁自保护硬面药芯焊丝的熔滴过渡模式主要是大滴排斥过渡,熔滴可以长大到焊丝直径的2倍左右;其飞溅率较低,在1%左右;绝大部分飞溅产生于熔滴脱离焊丝端部瞬间、熔滴落入熔池的瞬间、熔滴爆炸以及熔滴形成的初期。其中,对焊接过程影响不大的直径小于1 mm的小颗粒飞溅占较大比例,存在少量的直径在1~2 mm之间的中等大小颗粒飞溅,而直径大于2 mm的大颗粒飞溅在试验中出现的频率较低。 相似文献
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药芯焊丝CO2气体保护焊熔滴行为对药芯焊丝工艺性有直接的影响.采用焊接过程的高速摄影技术和汉诺威焊接质量分析系统对药芯焊丝的熔滴过渡形态进行观察分析.证实随着焊接参数的变化,药芯焊丝可能形成排斥过渡、表面张力过渡和细熔滴过渡.在排斥过渡时,由于大熔滴在焊丝端部较长时间的停留,出现明显的熔滴自身的爆炸飞溅,气体的强烈逸出飞溅等现象,表面张力过渡是介于大熔滴的排斥过渡与细熔滴过渡二者之间的一种过渡形式.细熔滴过渡时,焊接过程稳定、飞溅小、焊缝成形良好、生产效率较高,是药芯焊丝理想的过渡形式.在细熔滴的过渡的条件下形成的渣柱对熔滴的过渡起着导向作用. 相似文献
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针对不同焊接参数下SQJ501型、SQJS07型和SQJ50MX型药芯焊丝电弧焊的熔滴过渡行为进行了拍照,并对焊接飞溅进行了测量,研究药芯焊丝电弧焊的熔滴过渡行为及其焊接飞溅的基本规律.试验结果表明:三种药芯焊丝随着焊接参数的增大,均依次发生短路过渡、大滴排斥过渡和细颗粒过渡.SQJ501型和SQJS0MX型药芯焊丝电孤焊电弧形态呈锥形,SQJS07型电弧形态接近于钟形.SQJ507型药芯焊丝出现细颗粒过渡的焊接参数比其他两种焊丝大.焊接工艺参数以及焊丝种类影响了熔滴过渡行为进而影响焊接飞溅,细颗粒过渡时产生的飞溅最小. 相似文献
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本文分析了钛型渣系气保护药芯焊丝的电弧行为和化学冶金过程,探讨了药芯焊丝的焊接飞溅及焊缝中气孔工艺质量问题。结果表明,药芯焊丝熔滴过渡的基本形态是非轴向排斥过渡,焊丝的电弧形态属于活动、连续型,焊丝熔滴过渡受主导力控制。焊丝的焊接化学冶金过程是分区连续进行的。药芯焊丝熔滴过渡中伴随渣柱,以及渣柱直接进入熔池现象,可能导致焊接化学冶金反应不完全和;台金过程的新变化。药芯焊丝的焊接飞溅主要发生在非轴向排斥过渡的熔滴与焊丝之间的缩颈处,提出通过熔滴过渡指数控制焊接飞溅新观点。当气体从焊缝金属中逸出被阻止于焊缝中或被困于熔渣下面,就分别形成了气孔和表面压坑,提出了通过电弧中熔滴吸收氢的总重量控制焊缝中气孔的新思路。 相似文献
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从药芯焊丝的电弧形态和熔滴过渡形态以及影响因素、焊丝的发展和改进等方面,综述了钛型渣系气保护药芯焊丝研究的某些进展。结果表明,药芯焊丝熔滴过渡的基本形态是非轴向排斥过渡,焊丝的电弧形态属于活动、连续型,焊丝熔滴过渡受主导力控制。影响气保护药芯焊丝熔滴过渡的主要因素有:药芯组成物、焊丝截面形状、焊丝直径和钢带厚度、焊接工艺参数等。提出了通过熔滴过渡指数控制焊接飞溅和通过电弧中熔滴吸收氢的总质量控制焊缝中气孔(压坑)的新思路。焊丝内在质量关键技术是熔敷金属韧性稳定性的控制,必须重视焊丝生产线装备的技术先进性因素。 相似文献
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从药芯焊丝的电弧形态和熔滴过渡形态以及影响因素、焊丝的发展和改进等方面,综述了钛型渣系气保护药芯焊丝研究的某些进展.结果表明,药芯焊丝熔滴过渡的基本形态是非轴向排斥过渡,焊丝的电弧形态属于活动、连续型,焊丝熔滴过渡受主导力控制.影响气保护药芯焊丝熔滴过渡的主要因素有:药芯组成物、焊丝截面形状、焊丝直径和钢带厚度、焊接工艺参数等.提出了通过熔滴过渡指数控制焊接飞溅和通过电弧中熔滴吸收氢的总质量控制焊缝中气孔(压坑)的新思路.焊丝内在质量关键技术是熔敷金属韧性稳定性的控制,必须重视焊丝生产线装备的技术先进性因素. 相似文献
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采用高速摄影技术和汉诺威焊接参数分析仪,对国内外代表性的药芯焊丝CO2焊的熔滴过渡过程、电弧行为、飞溅、烟雾等电弧物理现象进行了大量的观察,总结了各种药芯焊丝熔滴过渡形式和电弧行为的特点,对各种过渡形式工艺性进行了初步评价. 相似文献
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Tokihiko Kataoka Rinsei Ikeda Moriaki Ono Koichi Yasuda Yoshinori Hirata 《Welding International》2013,27(7):517-522
Carbon dioxide (CO2) gas shielded arc welding is the main arc welding method, but it generates a large amount of spatter during welding. The root cause of spatter lies in the fact that the droplet undergoes repeated irregular shaking. To solve this problem, spatter generation modes were clarified and the effects of polarity and rare earth metal (REM) addition of the wire on CO2 gas shielded arc welding were investigated. As a result, when welding is performed with an electrode negative (DCEN) polarity using REM added wire, it was found that a conical arc plasma is formed, and the droplet which is transferred from the wire tip to the molten pool is fine and continuous, in what is termed ‘spray transfer’. Thus, spatter generation was reduced to 10% of amount of the conventional CO2 gas shielded arc welding (from 0.058 to 0.005g/s). 相似文献
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在熔化极气体保护焊过程中,采用大送丝速度,增大焊接电流和焊丝伸出长度是提高焊接熔敷率的直接途径.但当熔滴过渡转变为旋转射流过渡时,电弧不稳,飞溅增大,焊缝成形变差.施加不同频率的纵向交变磁场,对焊缝成形进行控制.采用高速摄像技术,拍摄焊接过程中的电弧形态和熔滴过渡,研究不同频率的磁场对熔滴过渡和焊接飞溅率的影响规律.结果表明,熔滴过渡形式不同,产生飞溅的机理不同;外加频率为1 000 Hz纵向交变磁场时,电弧的旋转半径减小,电弧的挺度增大,旋转射流过渡时电弧更稳定,焊接飞溅率降低,焊缝成形改善. 相似文献
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《Science & Technology of Welding & Joining》2013,18(8):740-746
AbstractMetal transfer phenomena and spatter generation in CO2 arc welding with a solid wire were investigated, and a low spatter welding process using a high frequency pulse rectangular current was developed. The optimal conditions of high frequency pulse CO2 arc welding were determined to be a peak current of 450–550 A and pulse frequency of 450–750 Hz. These high frequency pulse currents influenced the droplet oscillation due to resonance between the applied pulse frequency and the natural frequency of the droplet. A droplet was regularly transferred by 9–11 pulses, and the average interval of metal transfer was ~16 ms, which was half of that in conventional CO2 arc welding. The average droplet weight is 34 mg, showing a large reduction in comparison with that of the conventional method. As a result, the total spatter weight was reduced by 70% in comparison with the conventional method, and particularly large spatters more than 0·5 mm in diameter were reduced from 25 to 3 mg s?1. 相似文献
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In CO2 arc welding of solid wire, metal transfer phenomena and spatter generation are investigated with rectangular pulse current, and a low spatter CO2 arc welding process with high frequency pulse current is developed. The optimal conditions of high frequency pulse CO2 arc welding are in the range of peak current: 450–550 A and pulse frequency: 450–750 Hz. These high frequency pulse currents have the effect of droplet oscillation due to resonance between applied pulse frequency and the natural frequency of the droplet. The droplet is transferred consistently every 9–11 pulses and the average interval of metal transfer is about 16 ms which is reduced to half that of conventional CO2 arc welding. This average droplet weight is 34 mg, showing a large reduction in comparison with that of the conventional method. As a result, total spatter weight is reduced by 70% in comparison with the conventional method, and especially, large spatters more than 0.5 mm in diameter are reduced from 1.5 to 0.2 g/min. 相似文献
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为解决高强度Cr-Ni奥氏体焊丝脉冲GMAW电弧挺度不足,熔滴过渡不稳定的问题,文中采用高速摄像手段对Ar/He/CO2不同组合气体保护下的脉冲GMAW电弧形态与熔滴过渡进行了对比研究,以期优化混合气体成分.结果表明,氩气弧熔滴过渡容易,但电弧漂移、挺度差;氦气和CO2气体的加入可提高电弧挺度、增大电弧能量、熔滴过渡变为1脉多滴,先一个大滴,接着几个小滴;氦气的比例越大,第一个熔滴的尺寸越大;CO2气体可克服阴极斑点漂移,但比例不能超过5%;40% Ar+58% He+2% CO2三元组合的电弧挺度大,熔滴过渡均匀平稳,是奥氏体焊丝脉冲GMAW厚板焊接较理想的混合气体组分. 相似文献
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Summary This study deals with shielded metal arc (manual metal arc, MMA) welding and CO2 gas shielded arc welding, measuring the force required to remove adhering spatter from the surface of base metal by using different filler metals and by changing the conditions of the surface of the base metal. Rolled steel for general structural use (SS400) was used as base metal. A high titanium oxide type electrode and a low hydrogen type electrode were used for shielded metal arc welding, a solid wire and a flux‐cored wire were used as filler metal for CO2 gas shielded arc welding respectively. In order to examine the relationship between the condition of the surface of the base metal and the force required to remove spatter, a base metal whose surface was ground by an electric grinder, one which was not ground by an electric grinder, and another which was coated with an anti‐spatter compound were used for the experiments. Whichever filler metal was used, the spatter which adhered to the surface of the base metal was located within 100 millimetres from the weld line. In those cases, the force required to remove the adhering spatter can be measured as mostly below 98 N. The spatter needing more than 98 N to remove was located mostly within 20 mm of the weld line. No matter whether the scale was on the base metal or not, the difference of the force required to remove the spatter was small. When we used the base metal coated with anti‐spatter compound, in some cases we found spatter on the base metal, and in other cases we did not. When we found spatter, it was located within 40 millimetres of the weld line and the force required to remove it was below 20 N. 相似文献
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Masaya Shigeta Shota Nakanishi Manabu Tanaka Anthony B. Murphy 《Welding International》2017,31(9):669-680
For gas metal arc welding, the effect of CO2 mixture in a shielding gas on a metal transfer process was investigated through the observation of the plasma characteristics and dynamic behaviour at the droplet’s growth-separation-transfer by the temperature measurement methods which were suitable, respectively, to the argon plasma region and the metal plasma region. At the present experimental conditions, the metal transfer process was a spray transfer type with 100%Ar shielding gas. On the other hand, with 85%Ar + 15%CO2 shielding gas, the metal transfer process was a globular transfer type in which the arc length was shorter, the width was narrower and the time interval of the droplet separation was longer. For both shielding gases, the metal plasma region near the arc central axis exhibited 6500–7500 K, which was lower than the argon plasma region. With 85%Ar + 15%CO2 shielding gas, when the metal droplet grew below the electrode wire, the region below the droplet has a high plasma temperature and a high concentration of iron vapour which surrounded the droplet. The region also exhibited a remarkably high electron number density. At the spray transfer process, the argon plasma region had an electron number density twice as high as the metal plasma region. Meanwhile, at the globular transfer process, the metal plasma region had a higher electron number density than the argon plasma region, which corresponded to a higher electrical conductivity near the arc axis. This means that the electric current goes through the arc axis easier than the spray transfer process. This condition increases the temperature below the droplet. The thermal expansion increases the force preventing the droplet from falling down. In consequence, the metal transfer takes the globular transfer type. 相似文献
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Xiaoyu Cai Chenglei Fan Chunli Yang Xiangru Ji Li Hu 《Science & Technology of Welding & Joining》2017,22(5):446-453
The effects of shielding gas composition in tandem narrow gap gas metal arc welding were studied. The shielding gas included argon, carbon dioxide and helium. The arc characteristics and droplet transfer process were analysed. The results show that in the same welding parameters, the trail wire welding current is higher than the lead wire welding current. With the increase of carbon dioxide content, the welding currents of two wires decrease, and the trail wire droplet transfer mode transforms from spray transfer to projected transfer. With the increase of helium content, the welding currents increase and the lead wire droplet transfer mode transforms from projected transfer to spray transfer. The weld width is the largest when the shielding gas mixture is 80%Ar10%CO210%He. 相似文献
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分析了压力环境下气体混合比对脉冲MAG焊飞溅率及焊缝熔池形状的影响. 结果表明,压力环境下相同比例的保护气体在流速不变的情况下,起活性作用的气体组分相对较多,电弧弧柱紊乱加剧,飞溅剧烈,焊接过程极不稳定. 为获得高气压环境下稳定的焊接过程,减小飞溅率,通过提高混合气体配比中氩气体积分数来降低活性气体造成的能量损失,从而减少飞溅. 防止缺陷的产生. 综合考虑飞溅率、熔滴过渡稳定性及焊缝熔池形状等因素,在0.3 MPa环境压力下使用90%Ar+10%CO2混合气进行焊接可获得最佳的焊接效果. 气体配比的有效调节对于提高高气压环境下脉冲MAG焊焊接过程稳定性和焊接质量具有显著作用. 相似文献