铝合金电阻点焊热声场研究

Study on aluminum alloy resistance spot welding thermoacoustic field

电阻点焊是电阻焊技术的重要组成之一,该工艺具有能量集中、生产效率高、易于实现自动化等特点,是一种不可或缺的材料加工方法,被广泛应用于多个领域。点焊工艺又是一个电、热、力等多因素耦合的复杂过程,工艺过程非常短,而且熔核无法直接观测,增加了对其进行有效地质量检测的难度。目前,超声波等多种检测技术取得了一定的效果,但仍存在诸多不足。本文依据热声理论,研究铝合金电阻点焊的熔核尺寸与热声场规律,为进一步利用热声效应反演熔核尺寸信息做好铺垫,从而可以以此熔核信息来判断焊点质量,为电阻点焊质量检测提供新的途径。在热声理论的基础上研究了铝合金电阻点焊熔核尺寸与热声发射之间的关系,并且利用Matlab软件编程计算,模拟了不同形状尺寸点焊熔核的热声发射情况。结果表明:随着熔核半径的整体增加,工件表面热声压幅值呈上升趋势;熔核不同方向的热声压幅值随着该方向上熔核半径的增大而逐渐降低。

Resistance spot welding(RSW) is an important component of resistance welding technology,and this process has the advantages of energy concentration,efficiency and easy to automate,which is an indispensable material processing method.It is widely used in various fields.RSW is a process with many factors coupling impact,for example,electric,heat,power,and so on.This process is very short,and the nugget cannot be directly observed,these factors bring more difficult to its quality control effectively.Currently,ultrasound and other testing techniques have done a good job;however,there are still many deficiencies of them.According to the study of resistance spot welding nugget size and the thermoacoustic field law based on thermoacoustic theory,it will pave the way for inversion of nugget size in the further by using of the thermoacoustic effect,which can also be used to judge the quality of solder joints nugget for resistance spot welding quality testing.In this article,it has been interviewed that the relationship between nugget size and thermal acoustic emission based on thermoacoustic theory,and different shape and size nugget thermal acoustic emission has been calculated and simulated using Matlab software program.The results show that: with the overall increase of the nugget radius,the sound pressure of workpiece surface thermal amplitude is rising;the sound pressure of thermal amplitude of nugget different direction gradually reduce with the increase of the direction nugget radius.