焊枪喷嘴结构对保护气体流场的影响

1.中国石油天然气管道科学研究院有限公司;2.中国石油管道局工程有限公司国际分公司

管道焊接;模拟仿真;焊枪喷嘴;保护气体

Influence of welding torch nozzle structures on shielding gas flow field
LIANG Mingming1,LIU Xiaowen1,HOU Hao2,CHEN Jiaming1,NIU Lianshan1,JIANG Yanpeng1

1.China Petroleum Pipeline Research Institute Co. Ltd.; 2.China Petroleum Pipeline Engineering Co. Ltd. International Branch

pipe welding, simulation, welding torch nozzle, shielding gas

DOI: 10.6047/j.issn.1000-8241.2024.04.010

备注

【目的】传统焊枪喷嘴结构设计中存在开发周期长、成本高、保护气体流场保护效果不明确的问题,优化焊枪喷嘴结构、控制保护气体流场等显得尤为必要。【方法】采用计算流体动力学软件Fluent,针对保护气体流量、焊枪喷嘴结构、喷嘴与坡口的间距等关键参数进行数值模拟,并通过气体染色试验与焊接试验,对模拟结果进行验证。【结果】在管道窄间隙坡口熔化极气体保护电弧焊(Gas Metal ArcWelding,GMAW)工艺中,选用20L/min的保护气体流量可以获得良好的保护效果;锥形与扁锥喷嘴效果较为理想,其中扁锥喷嘴结构使得保护气体的流场呈现较小的圆锥度且流动更为挺直,在相对较低的保护气体流量下即可有效抵抗侧风干扰,保持稳定的焊接环境;当焊枪喷嘴与坡口的间距控制在15mm以内时,保护气体的流场具有良好的保护效果。采用气体染色试验及焊接试验对锥形与扁锥喷嘴的模拟结果进行验证,流场及焊接质量与模拟结果相符,表明采用数值模拟方法对保护气体流场的优化设计是切实可行的。【结论】计算流体动力学模拟技术能有效优化焊枪喷嘴的结构设计、缩短研发周期、增强焊接质量的稳定性,并显著提高窄间隙坡口GMAW工艺中保护气体的利用效率,可为焊枪喷嘴结构设计及保护气体流场的调控提供新的思路与技术参考。(图9表1,参[22]
[Objective] This paper seeks to address shortcomings in the conventional structural design of welding torch nozzles, such as prolonged development cycles, high costs, and uncertainty regarding the efficacy of shielding gas flow field protection. [Methods] The fluid dynamics computational software Fluent was utilized for numerical simulations, concentrating on critical parameters like shielding gas flow rates, welding torch nozzle structures, and nozzle-to-bevel spacings. The simulation results were subsequently verified and analyzed through gas dyeing experiments and practical welding operations. [Results] In the gas metal arc welding (GMAW) process context involving narrow-gap bevels, a shielding gas flow rate of 20 L/min yielded effective protection to pipes. The conical nozzle and the flat conical nozzle presented ideal results in which the flat conical nozzle structure helped the shielding gas flow field obtain minimal conicity and straighter flow, fostering stable welding conditions by efficiently resisting crosswind disturbances at lower flow rates. Ensuring a nozzle-to-bevel spacing of less than 15 mm produced a shielding gas flow field with enhanced protection. The subsequent gas dyeing experiment and welding operations mirrored the simulation results on the flow field and welding performance of the conical nozzle and flat conical nozzle, affirming the feasibility of simulation methods for optimizing shielding gas flow fields. [Conclusion] The study findings showcase the effectiveness of fluid dynamic computation simulation technology in optimizing the structural design of welding torch nozzles and accelerating the development cycles, significantly improving the utilization efficiency of shielding gas in the GMAW welding process with narrow-gap bevels, and enhancing the stability of welding quality. By emphasizing the important role of simulation in welding process improvement, this paper offers new insights and technical references for the structural design of welding torch nozzles and the regulation of shielding gas flow fields. (9 Figures, 1 Table, 22 References)
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