基于三维熔池形态的高速GMAW焊缝咬边缺陷产生机理与抑制措施的研究

项目名称： 基于三维熔池形态的高速GMAW焊缝咬边缺陷产生机理与抑制措施的研究

项目编号： No.51305235

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 机械、仪表工业

项目作者： 陈姬

作者单位： 山东大学

项目金额： 28万元

中文摘要： 制造业市场竞争的加剧，迫切要求企业通过提高焊接速度来提高生产率。但当GMAW焊接速度超过1m/min时，焊缝成形变差，产生焊道咬边缺陷，严重影响焊接质量和接头承受动载荷的能力。迄今，高速GMAW焊缝咬边缺陷的形成机制，尚未得到较全面和深入的揭示。本项目基于三维熔池流体动力学形态的分析与测试，深入研究高速GMAW熔池内液态金属的受力状态、温度分布和流动情况，定量分析不同工艺条件下熔池纵/横向受力特性及其对熔池表面变形、后向液体流流态和尾部液态金属堆积等的影响，建立高速GMAW熔池形态与焊道咬边的相关性模型。从三维熔池形态与纵/横向整体受力特性的角度，揭示和阐明高速GMAW焊缝咬边缺陷的产生机制及主要影响因素。采用小电流TIG电弧调控熔化极电弧行为，改善熔池的受力受热与流动形态，抑制焊缝咬边缺陷的产生倾向。为大幅度提高GMAW焊接速度、实现高适应性而低成本的高速GMAW焊接成形奠定坚实基础。

中文关键词： 咬边缺陷；高速GMAW；熔池流态；形成机理；抑制措施

英文摘要： With the unceasing intensification of manufacturing competition, the enterprise's demand for development of productivity with increased welding speed is becoming more and more urgent. However, if the welding speed is higher than 1m/min, the appearance of undercut defects will invoke worse weld formation. Desipite this phenomenon will severly affect welding quality and dynamic loading capacity of weld bead, the undercut formatin mechanism during high speed GMAW has not been comprehensively and profoundly revealed yet. Thus this project is aimed at studying the stress state, temperature distribution and convection flow of the liquid metal in the pool for high speed GMAW based on investigation and analysis of 3D weld pool dynamic behaviors. Then the force characteristics in weld pool on transverse/longitudinal direction are analyzed quantitatively under different welding processes, and its effects on weld pool deformation, backward molten flow behavior, and molten metal accumulation at rear are also studied. Hence 3D numberical models which reflect the correlation between molten pool behavior of high speed GMAW and undercut deffects are estabilished. The undercut forming mechanism and its influence factors are revealed and illustrated by the perspective of 3D welding pool behaviors and characterists of force in wel

英文关键词： undercut；high speed GMAW；weld pool dynamic；formation mechanism；suppression method