304不锈钢与聚对苯二甲酸乙二醇酯（PET）异种材料的焊接工艺研究

发布时间：2018-04-26 13:22

本文选题：304不锈钢 + 聚对苯二甲酸乙二醇酯　；参考：《江苏大学》2017年硕士论文

【摘要】：随着现代工业的迅猛发展,人们对材料和结构的性能要求越来越高。许多工程结构和高端产品往往要求具有多种材料的性能,而这需要多种材料的共同作用来实现,采用的方式便涉及到异种材料的连接问题。作为工业和生活中应用最广泛的材料,金属和塑料具有各自独特的优良性能,对二者进行连接可以获得具有综合性能的结构,因此,对金属和塑料的连接研究具有很高的研究价值和广阔的应用前景。本文以304不锈钢和聚对苯二甲酸乙二醇酯(PET)为研究对象,对金属与塑料的焊接方法进行探索研究,为以后的发展应用提供参考。本文利用6KW光纤激光器对304不锈钢和PET进行激光搭接焊,采用金属侧激光照射焊和透射焊两种方式,在一定条件和参数下进行焊接。实验中发现采用激光透射焊不能获得有效的连接接头,分析是由于所用激光器功率过大,未能实现二者的激光透射焊接。而采用金属侧激光照射焊,则成功获得了具有良好外观和较高连接强度的接头,在最佳工艺参数下焊接获得的接头剪切强度可以达到PET母材的79%。通过不同参数下的焊接结果和接头极限抗拉载荷对比分析,总结了激光功率、焊接速度和离焦量对接头剪切强度的影响规律。然后通过光学显微镜和扫描电镜(SEM)观察分析接头形貌,利用X射线能谱分析(EDS)方法和傅立叶红外光谱分析对接头进行元素和基团检测。对结果进行分析探讨,推测304不锈钢和PET通过激光焊接获得较高连接强度接头的原因是铆接和化学键连接的共同作用。焊接过程中,一方面塑料充满凹槽形成铆接;另一方面金属元素与PET中的CO基团可能发生了反应达到化学键的连接。在金属侧激光照射焊的基础上,使用钨极氩弧焊(TIG)代替激光进行焊接研究。在一定工艺参数下进行搭接焊,实验成功实现了304不锈钢与PET的焊接,在最佳工艺参数下焊接获得的接头剪切强度可以达到母材的100%。接头成形美观,无烧损未焊合区等缺陷。对不同参数下焊接获得的接头进行拉伸试验,对比分析结果数据,总结焊接电流、焊接速度和电弧长度对接头剪切强度的影响规律。接头的形貌通过光学显微镜和扫描电镜进行观察分析,采用X射线能谱分析和傅立叶红外光谱分析对接头元素和基团进行测试分析。对结果数据讨论分析,推测304不锈钢和PET的TIG焊接获得高强度接头的原因是铆接和化学键连接的共同作用。在焊接过程中,一是熔融塑料充满钢板凹槽中形成了铆接机制;二是不锈钢中的金属元素与PET的CO基团可能发生了化学反应而形成化学键的连接。对比激光焊结果,TIG焊获得了更高拉伸剪切强度的接头,原因是激光焊能量大且过于集中,降低了接头连接强度。
[Abstract]:With the rapid development of modern industry, the performance of materials and structures is becoming more and more demanding. Many engineering structures and high-end products often require the performance of many kinds of materials, and this requires the joint action of many kinds of materials. As the most widely used materials in industry and life, metals and plastics have their own unique excellent properties. The study of metal-plastics bonding has high research value and broad application prospect. Taking 304 stainless steel and polyethylene terephthalate (PET) as the research object, the welding method of metal and plastics is studied in this paper, which provides a reference for the future development and application. In this paper, the laser lap welding of 304 stainless steel and PET using 6KW fiber laser is carried out. The laser irradiation welding and transmission welding on the metal side are used to weld the 304 stainless steel and PET under certain conditions and parameters. It is found in the experiment that the laser transmission welding can not obtain the effective joint. The reason is that the laser power used is too large to realize the laser transmission welding. The joints with good appearance and high bonding strength were successfully obtained by using metal side laser irradiation welding. The shear strength of the joints obtained by welding under the best technological parameters can reach 79% of the PET base metal. The effects of laser power, welding speed and defocus on the shear strength of the joints are summarized by comparing the welding results with the ultimate tensile loads of the joints under different parameters. The morphologies of the joints were observed by optical microscope and scanning electron microscope (SEM). The elements and groups of the joints were detected by means of X-ray energy dispersive spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR). The results are analyzed and discussed. It is inferred that the joint of riveting and chemical bonding is the reason of laser welding of 304 stainless steel and PET. In the welding process, on the one hand, the plastic is filled with grooves to form rivets; on the other hand, the metal elements may react with the CO group in PET to reach the chemical bond. On the basis of metal side laser irradiation welding, tungsten argon arc welding (TIG) is used instead of laser welding. The welding of 304 stainless steel and PET was successfully realized by lap welding under certain technological parameters. The shear strength of the joint obtained by welding under the best process parameters can reach 100 parts of the base metal. The joint is beautiful in shape, no burning loss, no welding zone and other defects. The tensile test was carried out on the welded joints with different parameters. The effects of welding current, welding speed and arc length on the shear strength of the joints were summarized. The morphology of the joint was observed and analyzed by optical microscope and scanning electron microscope. The elements and groups of the joint were measured and analyzed by X-ray energy dispersive spectroscopy and Fourier transform infrared spectroscopy. Based on the analysis of the result data, it is inferred that the joint of riveting and chemical bond is the reason of the high strength joint obtained by TIG welding of 304 stainless steel and PET. In the welding process, one is riveting mechanism formed in the groove of molten plastics filled with steel plate, the other is that the metal elements in stainless steel may react with CO group of PET to form chemical bond. Compared with the results of laser welding, the joints with higher tensile and shear strength are obtained by TIG welding, which is due to the high energy and concentration of laser welding, which reduces the joint strength.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG44

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