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研究了电极表面处理和电极材料对镀镍钢板和镍板微型点焊时电极粘附的影响。结果表明:电极表面涂敷TiC后能提高CuCrZr电极和GlidCop60电极的抗粘附性能,其原因是涂层中的TiC能阻碍电极和镀镍板之间的局部焊接;GlidCop60电极的抗粘附性能优于CuCrZr电极的抗粘附性能,其原因是弥散分布于GlidCop60电极中的Al2O3能阻碍电极和镀镍板之间的局部焊接。 相似文献
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研究了表面处理对微型点焊镀镍钢板和镍板时电极失效的影响.结果表明:微型点焊镀镍钢板和镍板时电极的失效主要是电极头部的塑性变形以及电极和镀镍板之间局部焊接的断裂发生在电极表面而导致的电极磨损;表面涂敷TiC的CuCrZr电极的寿命(1 200点)是CuCrZr电极寿命(600点)的两倍,表面处理能提高电极寿命的主要原因是表面涂敷的TiC颗粒能阻碍电极和镀镍板之间的局部焊接,以及减小电极表面的塑性变形. 相似文献
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点焊镀锌钢板时电极表面熔敷TiC涂层对电极失效的影响 总被引:12,自引:1,他引:12
利用SEM、EDx和XRD等方法分析了在点焊镀锌钢板时电极表面熔敷TiC涂层对电极失效的影响.结果表明:点焊镀锌钢板时电极的失效机制主要是电极和镀锌板之间局部焊接的断裂发生在电极表面而导致的电极磨损,以及电极和镀锌板表面的锌之间的合金化.表面涂敷TiC的CuCrZr电极的寿命(1 200点)是CuCrZr电极寿命(500点)的2.4倍,表面处理能提高电极寿命的主要原因是在点焊镀锌钢板时表面涂敷的TiC层能阻碍电极和镀锌板之间的局部焊接和阻碍电极和镀锌板表面的锌之间的合金化. 相似文献
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采用电阻点焊技术焊接TA2纯钛板和AZ31B镁合金板。研究了不同焊接参数(点焊电流、点焊时间和电极压力)对焊点拉剪强度的影响,分析Ti/Mg焊点界面区域微观组织构成及显微硬度分布。分析结果表明,Ti/Mg焊点拉剪强度随点焊电流、焊接时间和电极压力的增大呈现先增加后降低的趋势。当采用点焊电流10 kA,焊接时间8周波,电极压力4 kN等参数时,Ti/Mg焊点拉剪力达到最大值3.7 kN。能谱分析表明,Mg/Ti界面反应层由Mg_(17)Al_(12),α-Mg和TiAl_3等相组成,其具有最大显微硬度146 HV。 相似文献
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针对板管间接点焊过程中焊接变形较大,引起接头质量难以保证的问题.通过采集电极位移曲线,研究板管间接点焊过程中膨胀量和变形量的变化规律,分析不同焊接工艺参数(焊接电流、电极力和焊接时间)对该点焊过程的影响.结果表明,板管间接点焊焊接阶段,膨胀过程与变形过程相互耦合;保持阶段,在电极力作用下,焊接变形进一步加大,最大变形量随着电极力的增大和焊接热输入的增多而线性增加.发生喷溅时,电极位移曲线出现阶梯状畸变,可利用位移曲线斜率的变化评判该点焊的喷溅现象.研究结果为板管间接点焊过程在线监测与质量控制提供理论指导. 相似文献
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基于SORPAS软件,对1.4 mm厚的DP590镀锌钢双层板电阻点焊熔核形成过程进行了数值模拟,并对比不同焊接参数下熔核尺寸的模拟值与实测值。结果表明,在电极压力4 k N、焊接电流8.4 k A、焊接时间20 cyc参数下,最高温度在两钢板接触界面处,峰值温度为1 808℃;模拟了DP590镀锌钢板电阻点焊过程中形核的不同阶段熔核附近温度场分布情况,得到了钢板和电极的峰值温度随时间变化曲线;随着焊接电流的增加,熔核尺寸呈现逐增加的趋势,模拟结果与实测结果吻合,但在小电流条件下以及大电流飞溅条件下,模拟值与实测值误差仍较大。 相似文献
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在单因素轮换法的基础上,采用正交试验设计方法,研究了电阻点焊DX51D+Z冷轧热镀锌钢板时,焊接电流、预压时间、电极压力、焊接时间、维持时间的优化匹配对焊点质量的影响权重.通过对焊点拉伸和剥离试验分析表明,5个焊接工艺参数对焊点质量影响最大的是点焊电流,其次分别是电极压力、点焊时间、预压时间,而维持时间是相对最弱的影响因子.合理的焊接工艺参数为:点焊电流11 180A、预压时间40周、电极压力0.25 MPa、点焊时间17周及维持时间9周,此时能够获得外观成形良好、强度较高的焊点. 相似文献
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通过正交试验法研究DP590冷轧板电阻点焊性能。以剪切载荷为评价指标,通过极差分析和方差分析,研究工艺参数影响点焊接头拉剪载荷的显著程度,并获得DP590冷轧板的最优工艺参数,测量接头的熔核直径并分析其失效模式,观察接头显微组织。结果表明,焊接电流对剪切载荷的影响最为显著,其次为焊接时间,电极压力影响较小;最优工艺参数为:焊接电流8.5 k A,焊接时间360 ms,电极压力3.6 k N;当焊接电流大于5.5 k A时,接头失效模式均为熔核剥离失效;熔核区显微组织为板条状马氏体和贝氏体,热影响区组织为细小马氏体。 相似文献
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试验研究了超高强度硼钢板/镀锌双相钢板的电阻点焊接头质量缺陷及其产生原因,通过正交试验设计,重点讨论了焊接电流、通电时间和电极压力对点焊接头强度的影响.结果表明:超高强度硼钢板/镀锌双相钢点焊中超高强度钢板侧更易出现飞溅和烧穿问题,通电时间和焊接电流强度时点焊接头拉剪强度影响显著,这类钢板组合的焊接应优先采用大电流、短... 相似文献
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H Papkala 《Welding International》2013,27(1):13-17
In resistance spot welding of thin sheet–thick sheet–thick sheet joint, when the sheet thickness ratio is large (sheet thickness ratio = total thickness of sheet joint/thickness of the thin sheet positioned on the outside of the joint), how to stably secure the nugget between the thin sheet and the adjoining thick sheet is a key issue. If the sheet thickness ratio is so large, nugget formation between the thin sheet and thick sheet is extremely difficult. In order to control of the nugget (position of formation, shape, etc. of the nugget) during welding for three sheets joint with a high sheet thickness ratio, optimum welding process was investigated. The developed ‘two-step force, two-step current’ welding process was suitable for high sheet thickness ratio joint and relaxed the constraints on the sheet thickness ratio. In Step 1 (first part of welding period) of the welding process, a nugget is reliably formed between the thin sheet and thick sheet by applying conditions of low electrode force, short welding time, and high current. In the subsequent Step 2 (second part of welding period), a nugget is formed between the two thick sheets by applying high welding force and a long welding time. In the weld results of a three sheet joint (0.7+2.3+2.3 mm; sheet thickness ratio: 7.6) using mild steel GA (0.7 mm) as the thin sheet and 780 MPa high strength GA (2.3 mm) in the two thick sheets, ‘two-step force, two-step current’ spot welding process showed the wide available welding current range. 相似文献
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Jianhui Xu Tongguang Zhai 《JOM Journal of the Minerals, Metals and Materials Society》2008,60(7):80-83
This paper is a review of the recent studies of small-scale resistance spot welding (SSRSW) of a refractory alloy 50Mo-50Re
thin sheet (0.127 mm thick). The effects of seven important welding parameters—hold time, electrode material, electrode shape,
ramp time, weld current, electrode force, and weld time—were studied systematically in an attempt to optimize the welding
quality. The diameter of a weld nugget was found to be only 30–40% of the electrode diameter in SSRSW. This was due to the
relatively low electrode force used in SSRSW compared with the high electrode force employed in large-scale resistance spot
welding (LSRSW) where the diameter of the nugget was almost 100% of the electrode diameter. Large pores often found in the
nugget during SSRSW could result from shrinkage during solidification due to fast cooling or fromdue to agglomeration of residual
volatile elements absorbed during powder metallurgy processing of the material. 相似文献
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Jiasheng Zou Qizhang Zhao Zheng Chen 《Journal of Materials Processing Technology》2009,209(8):4141-4146
In order to increase the life of conventional copper electrodes in resistance spot welding of Zn-coated sheet steel, a multi-layer Ni/(TiCP/Ni)/Ni composite coating was deposited onto the copper electrode top surface by electro-spark deposition. Scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction and micro-hardness tests were employed to characterize the microstructure and property of the coating. The results showed that the copper electrodes with a dense Ni/(TiCP/Ni)/Ni coating slightly increased the resistance of the weld system and hence the welding current could be reduced to produce a weld with the same button size as that made by uncoated electrodes at a high welding current. The coating was gradually cracked during welding under the action of welding force, forming Ni/(TiCP/Ni)/Ni composite islands which were strongly adherent to and further, punched into copper substrate. The coating could significantly reduce the alloying between copper electrode substrate and molten Zn. As a result, coated electrode showed a much longer life than an uncoated electrode even though the welding current for coated electrode was lower than that for uncoated one. 相似文献
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Xiaoyun Zhang Guanlong Chen Yansong Zhang Xinmin Lai 《Journal of Materials Processing Technology》2009,209(5):2671-2675
Dual-phase (DP) steel is a kind of advanced high-strength steels (AHSS) developed specifically for automotive application due to its excellent formability and better crash absorption than other conventional AHSS. Resistance spot welding (RSW) is the dominant sheet metal joining method in automobile industry, whereas the weldability of dual-phase steel using conventional air gun is not so excellent for the weld lobe diagram under constant electrode force is too narrow. However, this disadvantage can be easily overcome by servo gun's electrode force control function. This paper mainly relates how to improve weldability of dual-phase steel by adjusting electrode force during spot welding process. By modifying the electrode force using an orthogonal experimental design method, the result shows that the width of weld lobe diagram of dual-phase steel can be nearly doubled. 相似文献
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《Science & Technology of Welding & Joining》2013,18(6):530-535
AbstractTo reduce weight and improve performance, hydroformed tubes are being widely used in automotive structure fabrication and the single sided sheet to tube resistance spot welding (SSRSW) is considered as a feasible method for joining a tube to other parts. However, in the sheet to tube SSRSW process, it is difficult to assure welding quality because of large welding deformation due to a lack of support inside the tube. The present paper investigates the influences of welding parameters, such as electrode force and welding current, on the welding deformation and quality of the sheet to tube SSRSW using electrode displacement and tensile shear tests. The effects of different electrode force patterns on the welding quality are investigated utilising the force characteristics of a servo gun. It is found that the welding deformation is influenced by both the electrode force and the welding current, and the tensile shear strength declines with larger electrode force and higher welding current. However, the tensile strength could be enhanced significantly and the welding deformation decreased greatly by reducing the electrode force in the welding stage or holding stage. In order to decrease manufacturing cost and improve weld quality, the reduced electrode force is recommended for the sheet to tube SSRSW process. 相似文献
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以不锈钢201和铝合金5052作为试验材料,添加镍箔作为中间层,配合钢上铝下的搭接接头形式,采用激光深熔焊方法进行了焊接试验,分析了热输入对焊缝成形的影响以及添加镍箔后接头力学性能与不锈钢/铝合金焊接性的变化,并提出了焊缝下凹深宽比r以表征焊缝对应力集中的敏感程度.结果表明,热输入升高会导致焊接过程中飞溅增加,焊缝宽度与下凹程度增大,熔穿深度升高;不锈钢焊缝金属嵌入到铝合金内的熔穿深度对焊缝的力学性能有着重要的影响;镍中间层的添加有效地改善了接头力学性能,扩大了可用的工艺参数范围. 相似文献