焊剂片约束电弧焊接制造高强钢三明治板研究

Sandwich plates, kinds of lightweight structure, have been widely accepted and used. A new method of welding T joint, plug welding by constricting arc with flux band, will be suggested in order to improve the manufacturing processes of Sandwich plates, which cause high cost of producting Sandwich plates and low joint performance. This method will offer a possibility of the special configuration, flexible design and cost saving in Sandwich structure. It is also meaningful in riching theory of welding arc and welding structure. This research bases on the consideration for the processes of flux band acting on arc contraction with the purpose of manufacturing Sandwich plates, therefore it is mainly focus on the following scientific issues: (1)The arc behavior in the special ultra-narrow gap with considering the effect of the assembly accuracy, welding process, the different components of flux, revealed the key point of principles of flux band constricting arc and weld penetration control on three sides and weld performance control; (2)The rules and control of Welding stress and strain of the structure and joint after periodic intensive flux band constricting arc weld; (3)Service behavior of structure taking into account the joint organization evolution and the joint performance under the complex heat source of flux band constricting arc welding and flux composition. The completion of this study can provide an effective T structure welding method, a new type of high efficient manufacturing method of Sandwich plates. It can also provide evidence of structural optimization to ensure quality, expand the basic theory of arc welding method.

三明治板作为轻量化结构已被广泛认可和使用，为改进由于制造方法制约的三明治板成本及接头性能问题，提出一种新的T型接头焊接方法：焊剂片约束电弧塞焊法，为三明治板特殊构型、灵活设计、节约成本提供可能。在丰富焊接电弧理论和焊接结构上具有重要意义。本课题围绕基于考虑焊剂带约束电弧问题的三明治板制造过程主要研究以下科学问题：（1）考虑装配精度、焊接工艺、不同焊剂带成分的超窄间隙焊道内焊剂片约束下的电弧行为、揭示焊剂片约束电弧本质及焊缝三面熔深控制与控性；（2）周期性密集焊缝下结构的应力应变规律及焊剂片约束电弧焊接的接头应力应变规律及有效预控；（3）考虑焊剂带约束电弧方法复杂热源形态和焊剂带成分的接头组织演变及接头性能的结构件服役行为研究。本课题的完成可提供一种有效的T型结构焊接方法，提供一种新型高效的三明治板制造方法，为保证结构质量提供优化依据，扩展弧焊方法的基础理论。

高效、可靠和性能优良的焊接方法是金属三明治板轻量化设计与制造的关键技术问题，国内外现有研究成果多存在理论和技术上的局限，尤其是针对高强钢三明治板焊接，现有激光加工往往存在接头连接宽度不足和气孔缺陷等问题，影响整板结构性能。本研究针对高强钢三明治板T形接头的加工难题，提出一种新型的“焊剂片约束电弧焊接方法”用于高强钢三明治板的制造。围绕该焊接方法从焊接工艺设备、焊剂片约束电弧机理、及不同工艺下（焊接电流，焊接电压，焊道间隙）的约束电弧行为、熔滴过渡特性、焊缝成形与缺陷控制及焊接变形与残余应力调控等焊接关键技术问题进行了系统的研究。建立了焊剂片燃烧作用下物理冶金反应模型和电弧攀升物理模型，揭示了焊剂片对于电弧的固壁约束作用和能量分配调控机制。通过分析焊接电流及电压的频谱特性结合对焊接过程的高速摄像观测，直观表达了焊剂片约束电弧焊接T形接头过程中不同熔滴过渡模式和熔池流动行为，并发现弧桥并存过渡和细滴过渡下的电弧稳定性最高，而成“桥”条件为焊剂片熔滴与金属熔滴接触，且金属熔滴体积需大于焊剂片熔滴体积。在理解电弧约束原理基础上，提出了整套焊剂片约束电弧焊接T形接头的设备，方法及工艺。并建立了焊接变形与应力分析数值模型，建立了复杂应力条件下的焊接接头变形与失效断裂模型，以此优化焊接工艺，获得性能优于激光焊接的T形接头及三明治板最基本长焊缝单元件，为高效制造高强钢三明治提供了新的工艺与技术选择。