镁合金激光-TIG焊接温度场的红外测量与数值模拟

以变形镁合金AZ31B为研究对象,采用红外热像仪拍摄镁合金激光-TIG复合热源焊接过程中的焊接温度场,提出一种基于红外辐射测温原理.并针对红外热像仪的焊接温度场校正方法,采用热电偶验证该校正方法的准确性.利用数值模拟方法模拟整体温度场.试验结果表明,实温校正可准确校正试件表面状态一致区域的温度场,而表面校正可消除试件表面状态改变而引起的对温度场分布的影响,结合实温与表面校正方法能准确地校正镁合金激光-TIG复合热源焊接过程中电弧覆盖范围外的温度场,焊接温度场数值模拟可以比较准确预测并反映整体焊接温度场实际分布.

Infrared measurement and numerical simulation of temperature field in hybrid laser-TIG welding process of magnesium alloys

The infrared thermal imaging system was used as a sensor to measure the temperature field of wrought magnesium alloy AZ31B during the laser-TIG hybrid welding process. And a method for calibrating the welding temperature field was proposed, that was based on the infrared temperature measurement theory and was directed toward the infrared thermal imaging system. Thermocouple was applied to verify the accuracy of the calibrated method. And numerical simulation method was used to simulate the whole welding temperature field. The experiment results showed that real temperature calibrated method was able to calibrate the temperature field accurately when the plate surface condition was uniform, and surface calibrated method was able to keep the influence caused by the plate surface condition alternation from the temperature field distribution. With the combination of real temperature calibrated method and surface calibrated method, exact temperature field of magnesium alloy outside the arc covering area during laser-TIG hybrid welding process was obtained. Welding temperature field numerical simulation method was able to forecast and reflect the real distribution of whole welding temperature field accurately.