钢-铝合金薄壁管压缩塑性连接成形性分析

Formability Analysis of Steel-Aluminum Alloy Thin-Walled Tubes inPlastic Compression Joining Processes

摘要:

以St16钢管和6061铝合金管为对象，分析了一种新的薄壁管塑性连接方法连接这2种金属薄壁管的可行性。基于Abaqus软件建立了压缩塑性连接仿真模型，设计了薄壁管塑性连接专用模具，通过实验对仿真模型进行了验证。重点讨论了压缩塑性连接过程中管坯的相对自由长度、模具与管坯间隙、芯棒与管坯间隙对成形性的影响规律。结果表明，基于压缩形成褶皱的塑性连接方法适合于异质金属薄壁管的连接；压缩塑性连接的关键技术在于正确设计管坯自由长度、管坯与芯棒、管坯与模具间隙量，使被连接两管在压缩失稳之后的塑性变形量和变形方向协调，确保内外褶皱的波形轮廓接触紧密。对研究的St16/AA6061薄壁管，管坯相对自由长度满足1.250<l_g/r₀<1.625、模具与管坯外表面间隙为0.07~0.20倍的壁厚、芯棒与管坯间隙为0.07~0.27倍的壁厚是压缩塑性连接成功的前提条件。

关键词:薄壁管;塑性连接;压缩失稳;异质金属;成形性

Abstract:

TakingSt16 and 6061 aluminum alloy tubes as objects, the feasibility of using a novel plastic joining method to connect these two thin-walltubes was investigated. A finite element model was built using the Abaqus software, and a special moldfor plastic joining of thin-walled tubes was presented. Experiments of tubes plastic joining were performed to verify the precision of the finite element model. The influence of the relative free length of the tube endgap between the die and the tube, and the gap between the mandrel and the tube on the formability of the joint adopted in the plastic compressionjoiningprocess was emphasized. The results demonstrated that the method of plastic joining by compression was a suitable approach for thin-walled tubesof dissimilar materials. The key technology was that the free length of the tubes and the gap between molds and tubes should be correctly designed.The plastic deformation of the two tubes in the compression instability was compatible.Theamountof deformation and the directionof the movement of the wrinkles should be compatible so that the two wrinkles could contact tightly. For the St16/AA6061 tubesinvestigated,the prerequisite condition for a success joining was that the relative free length should located between 1.250 and 1.625. The gap between the tube and the dieshould be between 0.07 and 0.20 times of the thickness of the tube while that between the tube and the mandrel should be between 0.07 and 0.27 times of the thickness of the tube.

Key words:thin-walled tubes;plastic joining;compression instability;dissimilar metals;formability