DP780高强钢胶接点焊过程声发射信号特征及接头强度预测

Acoustic Emission Signals Characteristics and Joints Strength Prediction During Weld Bonding of DP780 High-strength Steel

针对1.2 mm厚的DP780高强钢板进行胶接点焊正交实验,采集胶焊过程的声发射信号,辨析其信号特征,建立接头强度与声发射信号特征参数之间的关系。结果表明:胶焊过程的电极加载、熔核形核和电极卸载三个物理阶段产生三段声发射信号;相比电阻点焊过程,由于胶焊过程存在胶层的烧灼与气化,其熔核形核阶段前段产生的声发射信号的振铃计数和幅值大于电阻点焊,并且飞溅出现时,声发射信号幅值增大;对于未发生飞溅的胶焊过程,焊接接头的失效载荷与熔核形核阶段声发射信号特征参数的振铃计数和正峰值具有较好的线性正相关性,据此可为胶接点焊过程焊接质量的在线检测与控制提供依据。

The orthogonal experiment of weld bonding was carried out for 1.2 mm thick DP780 high-strength steel sheet.The acoustic emission(AE)signals during the welding process were collected and analyzed.The relationship between strength of joints and characteristic parameters of AE signals was established.The results show that the three physical stages that are electrode loading,nugget nucleation and electrode unloading produce AE signals of three stages in the weld bonding process.Due to the burning and gasification of the adhesive layer in the weld bonding process,the AE count and positive peak are generated in the front stage of the nugget nucleation stage,which are greater than those generated in the resistance spot welding process.And the amplitude of AE signals increases with the spatter appearance;there is a good linear positive correlation between failure load and the AE count and positive peak without spatter,which can provide a basis for on-line inspection and control of welding quality during weld bonding.