激光热丝焊电阻热控制及送丝参数优化

Control of resistance heat and optimization of wire feeding parameters in laser hot wire welding

关键词:  激光热丝焊  电阻热优化  高速摄像  红外双色测温  数值模拟

Key words:  laser hot wire welding  resistance heat  high speed imaging  infrared ratio temperature measurement  numerical simulation

摘要:

如何选择送丝参数从而获得合适电阻热是确保焊丝稳定过渡和高效熔覆的必要条件. 文中通过高速摄像观察电阻热对焊丝过渡行为的影响,采用红外双色测温对焊丝温度进行测量. 结果表明,导电嘴以下30 mm处焊丝的温度可作为最优电阻热的判据;利用数值模拟方法建立了焊丝非稳态导热模型,计算了导电嘴以下30 mm处焊丝的温度,从而可以预测最优电阻热对应的送丝参数. 对不同送丝速度下最优电流比较发现,一定电阻热下加热电流的平方与送丝速度的比值为常数,可用于快速选择最优电阻热的送丝参数.

Abstract:

In laser hot wire welding process, it is necessary to choose wire feeding parameters to guarantee proper resistance heat for stable metal transfer and high-efficiency deposition. In this paper, the influence of resistance heat on wire transfer was observed by high speed imaging, and the wire temperature under the optimal resistance heat was measured by the infrared ratio temperature measure. The experimental results show that the position 30 mm away from the contact tube end could be used as characteristic point, whose temperature was measured as the criterion of the optimal resistance heat. A transient heat conduction model of the wire was established and the characteristic point temperatures under different feeding wire parameters were calculated by numerical simulation. The wire feeding parameters for the optimal resistance heat were predicted based on the simulated results. By comparing the optimal currents under different wire feeding rates, it was found that the ratio of the square of current and wire feeding rate kept constant, which was helpful to choose wire feeding parameters rapidly.