Generation of a fine-grained microstructure in GMA-welded aluminium by modified filler materials for a reduction of solification cracks

通过改性填充材料在 GMA 焊接铝中生成细晶粒微观结构，以减少固结裂纹

• 批准号: 413693695
• 负责人: Professor Dr.-Ing. Volker Wesling
• 金额: --
• 依托单位: Institut für Schweißtechnik und Trennende Fertigungsverfahren
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/413693695?language=en
• 关键词: Generation; fine; grained; microstructure; GMA

The aim of the research project is to transfer the known grain-refining effect of certain elements during the solidification of aluminum alloys onto the weld metal during GMA-welding. By the coating of the welding wires with nuclei-forming elements, such as titanium, they are transported into the weld metal and thus contribute to grain refinement. Due to the fine grain formation in the weld metal, it is possible to significantly reduce solidification cracks. Furthermore, it will be investigated whether the grain refinement can be transferred to the self-hardening and extremely hot-crack-sensitive alloy types. In addition, a hardening of the weld material is to be realized in order to achieve a positive effect on the mechanical strength of the weld metal and partly to compensate the strength drop in the heat-affected zone by a supporting effect of the now stronger weld metal.The metal-glass technology is to be used to investigate the nucleation mechanisms of the coating elements in the weld metal. This makes it possible to virtually freeze the state of the melt and to make the distribution of the solidification nuclei visible in the scanning electron microscope by means of energy-dispersive X-ray radiation. This technology is intended to extend the level of knowledge about the formation of the weld metal during the GMA-welding of aluminum materials. In addition to the coating elements, other solidification nuclei occurring as a result of the welding process can also be made visible as well. A further object is the derivation of functional relationships for the formation of the micro-structure in the weld metal by the layer of grain-refining elements on the modified filler materials. Here, general relationships between grain size, mechanical properties, coating thickness and / or composition are to be developed.As a by-product of the investigations, the influence of the coatings on the welding process can be determined. This includes the influence on the arc length, the droplet transition and the penetration behavior. Here, too, the derivation of general principles is striven for.

该研究项目的目的是将铝合金凝固过程中某些元素的已知晶粒细化效果转移到GMA焊接过程中的焊缝金属上。通过用成核元素如钛涂覆焊丝，它们被输送到焊缝金属中，从而有助于晶粒细化。由于在焊缝金属中形成细晶粒，因此可以显著减少凝固裂纹。此外，将研究晶粒细化是否可以转移到自硬化和热裂纹敏感性极高的合金类型。此外，为了对焊缝金属的机械强度产生积极影响，并通过现在更强的焊缝金属的支撑作用部分补偿热影响区的强度下降，将实现焊接材料的硬化。金属玻璃技术将用于研究焊缝金属中涂层元素的成核机制。这使得可以通过能量色散X射线辐射在扫描电子显微镜中实质上冻结熔体的状态并使凝固核的分布可见。该技术旨在扩展铝材料GMA焊接过程中焊缝金属形成的知识水平。除了涂层元件之外，由于焊接过程而出现的其他凝固核也可以被显示。另一个目的是推导出通过改性填充材料上的晶粒细化元素层在焊接金属中形成微观结构的函数关系。在这里，需要研究晶粒尺寸、机械性能、涂层厚度和/或成分之间的一般关系。作为研究的副产品，可以确定涂层对焊接过程的影响。这包括对电弧长度、熔滴过渡和熔深行为的影响。在这里，也力求推导出一般原理。