摘要
以0Cr13Ni5Mo水轮机转轮用低碳马氏体不锈钢为母材,开展了内层为氦,外层为He+CO2的双层气流保护TIG焊工艺研究.内层通纯氦避免电极直接接触外层CO2而氧化烧损,外层添加活性气体CO2向熔池溶解活性元素氧改变熔池表面张力对流模式,进而增加熔深和焊缝深宽比.研究了外层气体中CO2含量的变化对电极保护和焊缝形貌的影响.结果表明,在双层气流保护TIG焊工艺下,电极氧化烧损得到有效抑制,焊接效率是传统TIG焊工艺的两倍以上;当焊缝氧含量在0.007 6%～0.012%(质量分数)范围时,表面张力对流由外对流改变为内对流,焊缝形貌迅速由浅宽型变为深窄型.
He and He+CO2 double shielded TIG welding process was proposed to study the electrode protection and weld shape variations of 0Cr13Ni5Mo low carbon martensite stainless steel used for hydraulic turbine runners.Pure inert gas(He) as inner layer,avoids the electrode directly contacting the outer layer active gas(CO2) and being oxidized.Addition CO2 to the outer layer shielding gas provides a surface active element(oxygen) which dissolves into the weld pool to change the Marangoni convection mode and weld shape.The results show that the electrode is successfully protected,and Marangoni convection changes from outward to inward to produce a deep and narrow weld when the weld oxygen content is between 0.007 6%~0.012% in weld metal.The double shielded TIG welding is more than twice the welding efficiency of the conventional TIG welding.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2011年第11期49-52,115,共4页
Transactions of The China Welding Institution
基金
国家自然科学基金资助项目(50874101)
关键词
电极保护
焊缝形貌
氧含量
表面张力对流
electrode protection
weld shape
oxygen content
marangoni convection
