激光与电弧协同调控缆式焊丝GMAW熔滴过渡行为及机理研究

Cable-type welding wire (CWW) gas metal arc welding is an innovative process arc welding with high quality, high efficiency and low consumption. However, it is difficult to meet the requirements of high strength steel welding with large heat input. And the droplet is too large and the metal transfer is unstable when using the small current, it will affects the weld forming and welding quality. This project intends to use instantaneous high density energy to irradiate the target position of droplet, and with the arc coordinated control the metal transfer behavior, to achieve a stable and controllable metal transfer at low current. Through the combination of experiment and theoretical analysis, the interaction behavior between laser and droplet is studied to master the dynamic mechanism of droplet formation, growth and off-wire, and constructing a coupling model of energy-multiple force coordinated control of metal transfer behavior. The dynamic evolution process of metal transfer is obtained by using multi-information acquisition system, the mechanism of droplet heat, force change and metal transfer stability will be analyzed to realize precise coordinated control of metal transfer. The coupling mechanism among multi-parameter, droplet thermal and force will be expound according to the characteristics of arc shape, metal transfer behavior and melting pool flow behavior. The correlation between laser and welding parameters-metal transfer behavior-melting pool flow-welding quality will be established. And the mechanism of metal transfer behavior of laser and arc force coordinated control of CWW GMAW will be revealed, which can provide technical and theoretical basis for the new high efficiency and low consumption, high quality, and refined high strength steel welding.

缆式焊丝GMAW是一种大电流、高效低耗的新型焊接方法，但存在热输入大难以满足高强钢焊接要求，尤其小电流时熔滴过大、过渡不稳定，影响焊缝成形和焊接质量。本项目拟采用激光瞬时高密度能量照射熔滴目标位置，与电弧协同控制熔滴过渡行为，实现低电流稳定、可控的细颗粒过渡。通过试验和理论分析相结合的方法，研究激光与熔滴的交互作用行为，掌握熔滴形成、长大和脱离焊丝的动力学机制，构建能量—多力协同调控熔滴过渡行为的耦合模型；利用多信息融合系统获得熔滴过渡动态演变过程，分析熔滴受热、受力变化和熔滴过渡稳定平衡机制，实现熔滴过渡精确协同调控；研究电弧形态、熔滴过渡和熔池流动行为特征，阐明多参数与熔滴之间热、力行为耦合机制；建立“激光与焊接规范参数—熔滴过渡行为—熔池流动—焊接质量”的相关性，揭示激光与电弧协同调控缆式焊丝GMAW熔滴过渡行为机理，为新型高效低耗、优质和精细化的高强钢焊接提供技术基础和理论依据。

缆式焊丝GMAW是一种大电流、高效低耗的新型焊接方法，但存在热输入大难以满足高强钢焊接要求，尤其小电流时熔滴过大、过渡不稳定，影响焊缝成形和焊接质量，而如何实现大直径缆式焊丝GMAW降低电流后熔滴过和焊接过程不稳定等问题是迫切需要解决的。由于波形控制、磁场、超声和机械等方法可以促进传统GMAW熔滴过渡，但对焊接电弧和熔滴过渡会产生干扰。而激光增强熔滴过渡方法具有可控、干扰小为解决这一问题提供了可行性。因此，本研究通过探究激光瞬时高密度能量照射熔滴目标位置，与电弧协同控制熔滴过渡行为，将试验与理论分析相结合明确了激光与电弧协同调控熔滴过渡的方法。研究结果表明：激光功率、焊接电流与照射位置是影响激光与电弧协同调控缆式焊丝GMAW熔滴过渡的主要因素，通过多信息融合系统对激光作用熔滴前后的电弧形态、熔滴过渡尺寸、熔滴频率和熔滴运动轨迹等信息进行分析，掌握了熔滴形成、长大和脱离焊丝的动力学机制，构建能量—多力协同调控熔滴过渡行为的耦合模型；结合激光蒸发特征、熔滴过渡静力平衡理论和激光作用熔滴上的熔滴运动特点，揭示激光对液态熔滴的作用机制。通过对不同激光功率与焊接工艺参数研究，明确了多参数影响激光与电弧协同调控缆式焊丝GMAW电弧行为、熔滴过渡行为以及熔滴对熔池的作用规律。基于流体动力学，结合重力、表面张力、电磁力和激光蒸发反冲力的情况下，建立熔滴熔池一体化数值模型，揭示了不同工艺参数下激光调控缆式焊丝GMAW熔滴对熔池流动行为、焊缝成形、焊接过程稳定性和焊接质量的影响规律。本项目从激光、缆式焊丝与电弧耦合作用机理、电弧、熔滴过渡与焊缝成形等方面进行研究，建立了“激光与焊接规范参数—熔滴过渡行为—熔池流动—焊接质量”的相关性，揭示了激光与电弧协同调控缆式焊丝GMAW熔滴过渡行为机理。这不仅为缆式焊丝GMAW低热输入控制和应用提供了新方法和新支撑，也为新型高效低耗和精细化的高强钢焊接推广应用奠定理论基础和工艺理论。