摘要
钛合金铸件在铸造过程中不可避免的产生夹渣、气孔和缩孔等内部缺陷,在缺陷挖除后采用TIG焊修复,形成与母材相异的焊接和热影响区组织。从ZTC4钛合金铸件的母材、焊接和热影响区等部位切取偶联试样和对比试样,在人工海水中进行电偶腐蚀和全浸腐蚀试验,测量电偶电流、腐蚀电位以及失重和腐蚀速率,同时进行金相组织和表面氧化层检测。结果表明,ZTC4钛合金铸件母材、焊接及热影响区的组织和表面氧化层厚度有较大差异,腐蚀电位相近,电偶电流接近0,失重和腐蚀速率很小,相互之间无明显电偶腐蚀倾向,具有良好的耐腐蚀性;表面粗糙度不影响腐蚀电位和腐蚀速率;表面氧化层具有较强钝化和自愈能力,遭破坏后可迅速修复,无明显腐蚀迹象。
During the casting process,titanium alloy castings inevitably have internal defects such as slag inclusion,porosity and shrinkage cavity.After the defects were removed,TIG welding was used to repair them,forming the structure of welding and heat affected zone different from the base metal.The coupling samples and comparison samples were cut from the base metal,welding and heat affected zone of ZTC4 titanium alloy castings.The galvanic corrosion and full immersion corrosion tests were carried out in artificial seawater.The galvanic current,corrosion potential,weight loss and corrosion rate were measured,and the metallographic structure and surface oxide layer were detected.The results show that the microstructure and surface oxide layer thickness of base metal,welding and heat affected zone of ZTC4 titanium alloy casting are quite different,the corrosion potential is similar,the galvanic current is close to 0,the weight loss and corrosion rate are very small,and there is no obvious galvanic corrosion tendency between them,and it has good corrosion resistance.Surface roughness has no effects on the corrosion potential and corrosion rate.The surface oxide layer has strong passivation and self-healing ability,which can be quickly repaired after being damaged without obvious corrosion signs.
作者
韩云飞
乔海滨
孙宏喆
侯佩华
李渤渤
刘茵琪
杨学东
HANYunfei;QIAOHaibin;SUNHongzhe;HOUPeihua;LIBobo;LIUYinqi;YANGXuedong(Luoyang Sunrui Titanium Precision Casting Co.,Ltd.,Luoyang 47100,China;Luoyang Ship Material Research Institute,Luoyang 471000,China)
出处
《热加工工艺》
北大核心
2024年第14期142-146,共5页
Hot Working Technology
基金
国家重点研发计划项目(2020YFB2008300,2020YFB2008301)。
关键词
ZTC4钛合金铸件
电偶腐蚀
人工海水
焊接组织
ZTC4 titanium alloy casting
galvanic corrosion
artificial seawater
welding structure
