铝合金激光焊接工艺特性研究

结合近年铝合金激光焊接的研究情况,阐述了铝合金激光焊接与复合焊接的特点以及研究现状,分析了铝合金的焊接特性以及焊接工艺参数对焊接质量的影响,讨论了激光焊接时存在的问题和解决措施。     

铝合金激光焊接技术的发展现状

介绍了近年发展起来的基于激光热源的铝合金焊接技术。它主要包括5种方法：激光辉、电孤强化激光焊、双束激光焊、顺序电弧激光焊、激光辅助焊接，讨论了每种方法的特点和作用机理。     

铝合金激光焊接

概述了铝合金的焊接特性以及焊接过程中的难点,由于铝高反射、导热快的特点,激光焊接也不可避免地存在一般熔焊常遇到的焊缝气孔、焊接热裂纹等问题。鉴于铝合金自身特点,也使激光焊接工艺更加复杂,亟待改进和完善。提出了相关改进措施,通过表面处理、改善焊接接头、调整焊接波型参数等来改善铝合金焊接性能。     

铝合金激光焊接技术研究进展

综述铝合金激光焊接技术特点及研究现状,开展3 mm厚LF6铝合金激光-MIG电弧复合焊接工艺研究。文献综述表明,铝合金激光自熔焊接表面成形不好,且易于产生气孔缺陷,激光填丝焊、激光-电弧复合焊以及双光束激光焊等能够有效地解决上述铝合金激光焊接问题。试验研究表明,激光-MIG电弧复合焊接LF6铝合金可获得良好的焊缝成形,内部质量达到QJ1666A-2011Ⅰ级焊缝质量要求,接头强度达到母材的90%以上,具备较为优异的力学性能。     

铝合金激光焊接研究现状

概述了铝合金激光焊接的难点,分析了铝合金激光焊接的质量问题。针对质量问题提出了解决措施,并论述了铝合金激光焊接在国内外的应用。     

铝合金激光焊接的工艺特性及其发展现状

概述了铝合金激光焊接的工艺特性及难点,指出了铝合金激光焊接技术的研究现状及发展方向。     

铝合金激光扫描焊接工艺特性

为减少6061铝合金激光焊接缺陷,提高焊接过程稳定性,采用大功率固体激光光束扫描焊接的方法进行焊接工艺开发. 结果表明,当工艺参数在扫描幅度为0.5 ~ 0.7 mm,扫描频率为100 ~ 200 Hz范围内时可以获得质量较高的焊缝. 激光扫描焊接可以明显抑制等离子体的生成,其尺寸相对于常规激光焊接的2/3,其面积变化标准差约为常规激光焊接的1/2. 相对于常规激光焊接技术,激光扫描焊接过程中熔池形状稳定保持圆状,匙孔在其中沿逆时针方向稳定运动,其面积约为常规激光焊接中匙孔面积的2倍.     

激光在铝合金焊接中的应用研究进展

近年来,随着激光器技术的进步,激光在铝合金焊接中的应用研究日益受到关注.本文综述了国内外研究者为提高铝合金焊接过程中激光能量的耦合效率所做的各种努力和尝试,总结了激光复合焊接、铝合金激光焊接模拟及其焊接过程稳定性的研究进展,最后对今后铝合金激光焊接技术的研究热点和发展趋势做出了预测.     

激光焊接铝合金电视机面框

简述铝合金电视面框工艺现状,详细分析激光焊接工艺在铝合金电视机面框上应用的具体工艺实施过程,为激光焊接技术在家电产品上的应用提供案例参考。     

铝合金激光双光点焊接工艺特性

对铝合金薄板激光单光点和双光点焊接(包括不填丝和填丝)的焊缝成形、对接间隙和准直度容许裕度以及气孔状况进行了比较,并分析了双光点能量分布的激光对铝合金焊接的影响.结果表明,与激光单光点焊接相比,激光双光点焊接铝合金所得焊缝表面质量更好,焊缝熔宽更大,对接间隙和准直度容许裕度明显放宽.激光双光点焊接铝合金可以显著减少焊缝中大气孔的数量,但对焊缝中小气孔数量的影响不明显.此外,填加焊丝可以进一步改善焊缝表面质量并放宽对接间隙和准直度容许裕度,但将增大焊缝产生大气孔的倾向,采用激光双光点焊接仍可使焊缝中大气孔的数量明显减少.     

Resistance welding of aluminium and aluminium alloys

Special features of the process of resistance welding of aluminium and its alloys and also equipment manufactured by the CEA and supplied by Weber Comechanics are described.     

Application of thermal modelling to laser beam welding of aluminium alloys

Abstract

A thermal model has been developed for laser welding which describes the heat input in terms of point and line sources. The model was used to generate weld profiles which closely matched those found by experiment. Outputs of the model (the thermal gradient G_L and the growth rate R) were used to describe the macroscopic grain structure found along the weld centreline. Columnar structures were predicted at low welding speeds (high G_L/R ratio) and equiaxed structures at high welding speeds (low GL/R ratio). Using the thermal model, cooling rates of ～1500 K s^–1 were estimated for the lowest welding speed, which increased by an order of magnitude for the highest welding speed considered. There was excellent agreement between the dendrite secondary arm spacings measured by experiment and those predicted using the thermal model.     

铝合金激光焊温度场计算及测试

根据二维瞬态温度场模型,针对铝合金激光焊得出温度梯度解析式。对激光焊接工艺参数峰值功率、焊接速度、离焦量三因素进行正交试验,得出最佳工艺参数。在最佳工艺参数条件下,采用Matlab公式,计算出温度梯度曲线。结果表明,随着与焊缝中心距离的增大,瞬态温度逐渐降低。采用温敏试纸对焊缝周围进行温度测试,测试结果与理论计算结果一致。     

Hybrid laser-arc welding of aluminium alloys

Special features of laser welding of aluminium alloys with laser and arc heat sources are investigated. Advantages and shortcomings of these methods are noted. Experiments were carried out to combine laser and arc heat sources for welding aluminium alloys. Equipment for hybrid welding is described. The technological parameters influencing the external formation of the welded joints are determined. Specific conditions for welding 1424 aluminium alloys with a thickness of 4.0 mm are presented. High-quality welded joints were produced by hybrid laser-arc welding in 1424 alloy with a thickness of 4.0 mm.     

Tandem MIG welding of aluminium alloys

Welding processes used in transport system manufacturing, such as the automotive industry, have in recent years seen a pronounced trend towards fabrication of lower-cost welded structures through efficiency enhancement focused on weld quality improvement. In this context, arc welding processes providing sufficient weld reinforcing ability, while allowing higher-speed welding are expected to emerge. In welding of aluminium alloys, MIG welding conferring superior economy and profitability holds out particularly high expectations, in future set to be the mainstream process for fabrication of welded structures. In MIG welding, however, straightforward adoption of higher welding speeds for efficiency enhancement purposes leads to loss of joint quality and weldpool turbulence due to increased current. Welding speeds therefore normally have an upper limit of around 1.5 m/min.¹ More recently, however, further welding speed increases have been sought through improvement of wire feed¹ and power supply² systems.     

Laser beam welding of wrought aluminium alloys

Abstract

Laser beam welding is now a common manufacturing method for a wide range of steel products from automobiles to razor blades. However, the process has only recently been approved for critical applications involving aluminium alloys, notably in the aerospace and automotive industries. The properties of aluminium alloys influence the interaction between the beam and the material to a far greater extent than for steels. The challenge of developing industrial welding procedures has therefore been considerable. The present review describes the effects of CO₂ and Nd–YAG laser beam processing parameters and the properties of the most common wrought aluminium alloys on the characteristics of welded joints. Porosity, solidification cracking, and poor weld bead geometry are shown to be the most frequently encountered imperfections. These can be eliminated through the use of appropriate filler materials, process gases, material preparation, and in some instances, adaptive control systems. Very little work has been reported on the corrosion properties of laser welded aluminium alloys. Experimental processing parameters are presented and compared using an analytical model, which can also be employed for predictive purposes. A number of industrial applications are described. These demonstrate that, for specific alloys, the process is now sufficiently well understood to be approved for high volume production, particularly in the transport industries.     

Friction stir welding of aluminium casting alloys

The results of testing friction stir welding quality in relation to EN AC-43200 (AK9) and EN AC-45000 (AK64) aluminium casting alloys are presented. The test joints were made with the use of a welding machine constructed on the basis of numerically controlled milling machines. The assessment of the joint quality was made based on visual inspection, mechanical testing, weldment structure analysis and hardness tests. The purpose of the investigation was to discover the possibility of friction stir welding of casting alloys and the influence of welding conditions on joint properties and structure. The test results show good weldability of aluminium casting alloys by the FSW method. Sound welds can be obtained in a relatively wide range of welding parameters while the weld strength is satisfactory. In order to obtain the highest quality joints, the workpieces must be pressed onto the other, while the welding process cannot run with excessively high speed. The best mechanical properties of the joints were achieved when the friction process was conducted at a rotational speed of the mixing tool of 900 rpm.