摘要
GMAW自动打底焊易出现未焊透及焊漏现象,成为焊接自动化的瓶颈问题。以焊缝背面熔宽作为表征熔透状态的参考信息,探究对打底焊接质量影响较大的焊接电流、焊接速度、坡口间隙及坡口角度4个焊接工艺参数对背面熔宽的影响规律。开展GMAW打底焊接试验研究,分析背面熔宽随上述焊接参数的变化趋势。试验结果及分析表明:随着焊接电流的增大,背面熔宽呈上升趋势,熔透状态由'未熔透'过渡到'过熔透';随着焊接速度的增大,背面熔宽呈下降趋势,熔透状态由'过熔透'过渡到'未熔透';背面熔宽随着坡口间隙与坡口角度的增大而增大,过小的坡口间隙与角度易产生'未熔透'。鉴于背面熔宽随4个焊接工艺参数增加而单调增加或单调减少,采用多元线性回归方法建立4个参数与焊缝背面熔宽的数学模型,该模型通过了回归模型的拟合优度检验、整体检验及回归系数检验。通过GMAW试验对数学模型进行了验证,结果表明建立的回归模型数学表达式能够对焊缝背面熔宽尺寸进行较为准确的预测,为GMAW自动打底焊参数调节提供指导。
'No penetration' and 'Excessive penetration' are easy to appear in automatic backing GMAW, which becomes the bottleneck of welding automation. Taking the back-bead width as the reference information characterizing the penetration state, the influences of the 4 welding parameters of welding current, welding speed, groove gap and angle on the back-bead width are studied. The backing GMAW tests are carried out, and the data analysis of the results show that, with the increase of the welding current, the back-bead width increases, and the penetration state changes from 'No penetration' to 'Excessive penetration'; with the increase of the welding speed, the back-bead width decreases, and the penetration state changes from 'Excessive penetration' to 'No penetration'; the back-bead width increases with the groove gap or angle, and the small gap and angle are easy to cause 'No penetration'. Since the back-bead width increases or decreases monotonously with the increase of each welding parameter, a mathematical model of the 4 welding parameters and back-bead width is established by the multivariable linear regression, which passed tests of Goodness of Fit, Overall Significance of Regression and Significance of Variables. The mathematical model is verified by GMAW tests, and the results showed that the mathematical expression of the regression model can predict the back-bead width accurately. The study provides guidance for the parameters adjustment of automatic backing GMAW.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2018年第18期55-61,共7页
Journal of Mechanical Engineering
基金
国家自然科学基金(51505035)
北京市教委科技计划重点(KZ201810017022)
北京市科技计划课题重点(Z171100000817008)资助项目
关键词
打底焊
背面熔宽预测
多元回归模型
熔化极气体保护焊
自动焊
backing welding
back-bead width prediction
multivariable regression model
gas metal arc welding
automatic welding1
