焊接过程热传导系数反演法

由传热学基本方程，推导出了由温度场全场信息反演热传导系数的数学模型。证明了焊接过程热传导系数反演法的可行性。结合红外热象法与热电偶测量了LY2铝合金固定TIG点焊过程的焊接温度场。参照温度场全场信息，通过计算分别获得了加热和冷却过程热传导系数随温度变化曲线。结果表明，焊接过程中温度变化方向对热传导系数的影响是显著的，即出现“滞后”现象。此方法可为准确模拟焊接温度场、应力应变场奠定基础。

Computation of thermal conductivity during welding by inversion method

On the basis of heat transfer function, the mathematical model of thermal conductivity inversion by full-field temperature information is deduced, and the feasibility of thermal conductivity inversion during welding is proved. Infrared thermography and thermocouple were combined to measure the welding temperature field during a fixed-point tungsten inert-gas arc welding on a LY2 piece. By full-field temperature information, the variation curves of thermal conductivity with temperature during heating and cooling were obtained. The results show that thermal conductivity values during welding are different with those under stable condition, and the temperature variation direction has a distinct effect on thermal conductivity, viz. thermal conductivity shows delay phenomenon during welding.