摘要
Abstract
To deeply investigate the forming rules of narrow gap laser-MAG hybrid welding seams of high-strength steel,25 mm thick Q690 high-strength steel was taken as the research object.The Box-Behnken Design(BBD)in the Response Sur-face Methodology(RSM)was used to design a three-factor and three-level experiment,systematically exploring the effects of laser power(P),welding current(I),and welding speed(V)on the forming of backing,filling,and cover seams.For differ-ent functional requirements of the seams,the melt depth and fusion ratio(backing seam),melt width and sidewall fusion ra-tio(filling seam),and width-to-height ratio and fusion ratio(cover seam)were selected as response indicators respectively.A quadratic regression prediction model for each forming parameter was constructed,the significance of the model was veri-fied through Analysis of Variance(ANOVA),and the relationship between process parameters and seam forming was quanti-fied using 3D response surfaces and contour plots.The results showed that in the backing seam,the laser power had the great-est impact on the melt depth,with optimal parameters being 3,800 W,240 A,and 0.7 m/min,achieving a stable melt depth of 5.6～5.7 mm;in the filling seam,the welding current had the greatest impact on the melt width,with optimal parameters be-ing 2,200 W,260 A,and 0.7 m/min,achieving a sidewall fusion ratio of more than 0.60,and it could be dynamically adjusted according to the groove spacing;in the cover seam,the welding speed had the greatest impact on the width-to-height ratio,with optimal parameters being 2,000 W,280 A,and 0.48 m/min,achieving a width-to-height ratio of more than 7.0 for smooth forming.Welding experiments were carried out using optimized process parameters,resulting in aesthetically pleas-ing seam formations without defects such as porosity or lack of fusion,and the radiographic inspection results met the stan-dards.Compared with traditional arc welding,this process reduced the groove filling area by 50.4%,decreased the welding heat input by 48.4%,and increased the welding efficiency by 47.8%,providing a reliable process plan and theoretical support for the efficient and high-quality welding of Q690 high-strength steel thick plate structures.关键词
Q690高强钢/窄间隙激光-MAG复合焊接/响应曲面法/焊缝成形规律/工艺优化Key words
Q690 high-strength steel/narrow-gap laser-MAG hybrid welding/response surface method/weld formation rules/process optimization分类
矿业与冶金
