摘要
采用富Ar混合气体TIG焊焊接了镁合金板材,分析了Ar、He、CO2和N2不同配比混合气体的电弧特性及其对焊缝成形、熔深、显微硬度和抗拉强度的影响。结果表明:富Ar混合气体加入一定比例CO2会造成镁元素蒸发,焊接过程中有飞溅现象,加入一定比例N2会在焊缝表面生成Mg3N2膜,影响焊缝质量。He-Ar混合气体随着氦气体积分数的增大,电弧稳定性增强,阴极热功率所占电弧总功率的比例减少。当He体积比等于50%时,电弧阴极区域明显收缩而阳极区域发散扩展,可获得外形美观、熔透率高、焊缝区组织均匀细小的镁合金焊接接头。焊缝的平均显微硬度为60HV,达到母材的82.6%,抗拉强度为186MPa,是母材的76%,断裂发生在热影响区,属于韧-脆混合断裂。
The magnesium alloy plates were welded by mixed gas of wealthy argon TIG welding. The arc physical characteristic and its influence on the welding quality were analysed under various volume ratio gas mixtures of At, He, CO2 and N2. The results indicate that mixed gas of wealthy argon by adding certain percentage of CO2 course evaporation of magnesium element and spattering, the quality of welding is affected by the membrane Mg3N2 gengerated in the surface of weldment by adding certain percentage of N2. The arc stability improves with the He volume ratio increasing, while the proportion of cathode hot power to the total arc capacity decrease. The cathode zone of electric are shrinks evidently and the anodic zone expands when the volume ratio of He gas is less than 50%, in addition, the good appearance weld of magnesium alloy with high penetration and homogeneous fine e- quiaxial grain was obtained. The average microhardnass of weldment reach 60HV which is 82.6% of the base plate, the tensile strength of weldment reach 186MPa which is 76% of the base plate and the fracture occurred in the heataffected zone, belonging to tough- brittle mixed morphology.
出处
《轻金属》
CSCD
北大核心
2009年第6期59-63,共5页
Light Metals
基金
郑州大学研究生科学研究基金项目(A154)
中国博士后科学基金资助项目(20070410875)
