锁底结构VP-TIG焊缝未焊透缺陷返修工艺

摘要

For the incomplete penetration defect of circumferential weld on the VP-TIG lack,a repair technology program is designed,and the optimal welding technology and welding parameters are confirmed by analyzing the internal quality,external quality,mechanical property at normal temperature and microstructure of the welds after repair.The result shows that for the incomplete penetration defect of 3～8 mm VP-TIG lock welds,promoting the ratio of He from 30％ to 70％,current frequency from 120 Hz to 200 Hz,duty cycle from 75％ to 82％ can improve the penetrability and realize the complete penetration.Meanwhile the welding current decreases from 220 A to 160 A to reduce the influence of welding heat input on the welding deformation and weld performance.The repair welds pass the X-ray test and their mechanical properties are good.%针对VP-TIG锁底环焊缝未焊透缺陷,设计返修工艺方案,分析返修后焊缝的内外部质量、常温力学性能和微观组织,确认最优返修工艺方式及对应工艺参数.结果表明,针对3～8 mm锁底焊缝未焊透缺陷,保护气中氦气比例由30％提升至70％、频率由120 Hz提升至200 Hz、占空比由75％提升至82％,可增大焊接电弧的穿透性,实现未焊透区域的焊透;同时焊接电流由220 A降低至160 A,以降低焊接热输入对焊接变形及焊缝性能的影响.补焊后的焊缝检测合格,力学性能良好.