一种便携高精度超声应力设备及焊缝残余应力研究

A portable high precision ultrasonic stress equipment and research on residual stress in welds

相比于XRD、盲孔法、磁弹性法,采用超声法对在役压力容器、钢结构件的残余应力、在线应力进行检测具有明显优势,但现有超声应力设备普遍稳定性不高、便携性差。文章介绍了一种自主研发的基于WiFi通信的高精度便携分体式超声应力检测设备,其硬件包括超声采集模块、超声探头、microPC上位机,软件包括设置、信号采集、信号优化、应力求解及标定等模块,并可通过快拆式通用滑动电池组供电。同时研究了Q235焊板平行和垂直焊缝方向的不同位置焊接残余应力。研究结果表明:平行焊缝方向残余应力保持稳定,且距离焊缝位置增大,残余应力减小;焊前预热可以降低残余应力;垂直焊缝残余应力小于平行焊缝残余应力值,其应力值等于检测位置平行焊缝残余应力值的平均值。

Compared with XRD,blind-hole method,and magnetic elasticity method,the use of ultrasonic testing has significant advantages in residual stress and online stress detection for in-service pressure vessels and steel structures.However,the existing ultrasonic stress equipment generally has poor stability and portability.This paper introduces a self-developed high-precision portable split-type ultrasonic stress testing equipment based on Wi Fi communication technology.The hardware includes an ultrasonic acquisition module,ultrasonic probe,and micro PC upper computer,while the software includes setting,signal acquisition,signal optimization,stress solution,and calibration modules.It can also be powered by a fast-detachable universal sliding battery pack.At the same time,the residual welding stress in different positions of Q235 welded plates in parallel and perpendicular to the weld direction was studied.The results show that the residual stress in the parallel weld direction remains stable,and the residual stress gradually decreases as the distance from the weld position increases.Preheating before welding can effectively reduce the residual stress.The residual stress of the perpendicular weld is smaller than that of the parallel weld,with its stress value equal to the average value of the residual stress of the parallel weld detected in the same position.