304不锈钢电水壶壶嘴腐蚀分析  

Analysis on corrosion of 304 stainless steel electric kettle spout

作　　者：杨玲 曹达华 万鹏 周瑜杰 YANG Ling;CAO Dahua;WAN Peng;ZHOU Yujie(Guangdong Midea Consumer Electric Manufacturing Co.,Ltd.,Foshan 528311,China)

机构地区：[1]佛山市顺德区美的电热电器制造有限公司,广东佛山528311

出　　处：《电镀与涂饰》2024年第12期92-102,共11页Electroplating & Finishing

摘　　要：[目的]304不锈钢电水壶壶嘴发生腐蚀的原因需要探明。[方法]选取从原材料到水壶制造不同阶段的样品,借助台式真空火花发射光谱仪、扫描电子显微镜、金相显微镜、X射线衍射仪、振动样品磁强计等仪器,从原始板材的成分、表面形貌与显微组织,壶嘴焊缝腐蚀前后的表面形貌与成分,壶嘴密集点焊后Cu残留的检测,以及诱发马氏体相变的可能性等方面进行分析。[结果]原始板材的化学成分基本符合304不锈钢的成分标准,其金相组织为正常的单一奥氏体组织。部分原始板材表面存在大小不一的凹坑,晶界上普遍存在连续沟壑,易导致壶嘴生锈。壶嘴焊缝处存在Al的氧化物,应源自磨料。在壶嘴焊接过程中,由于焊接压力过大,一方面引起基体形变,存在局部应力集中,使得该区域活性较大,导致使用过程中这些地方容易生锈;另一方面焊缝处局部应变诱发了马氏体相变,马氏体与奥氏体构成了腐蚀微电池,发生局部微电池腐蚀。[结论]提高对原始板材表面品质的要求,以及采用压力更小、受力更均匀的焊接方式代替密集点焊工艺,有助于解决上述问题。[Introduction]The reasons of corrosion of the spout of 304 stainless steel electric kettle need to be found out.[Method]The raw material and the samples selected from different phases of the electric kettle manufacturing were characterized by using desktop vacuum spark emission spectrometer,scanning electron microscope,metallographic microscope,X-ray diffractometer,and vibrating sample magnetometer.The composition,surface morphology,and microstructure of the original steel sheet,the surface morphology and composition of the spout weld before and after corrosion,the residue of Cu after intensive spot welding of the spout,and the possibility of martensitic phase transformation were analyzed.[Result]The chemical composition of the original steel sheet basically conformed to the standard of 304 stainless steel,and its metallographic structure was a single austenite,which is the same as the normal microstructure of 304 austenitic stainless steel.There were pits of different sizes on the surface of some original steel sheets,and existed continuous gullies on the grain boundaries,which tends to induce the corrosion of the spout.There was oxide of Al in the spout weld,which was probably introduced by the abrasive.During the spout welding process,the excessive welding pressure caused the deformation of the substrate.The local stress concentration made some local areas more active,where corrosion would tend to occur during the use of the kettle.Moreover,the local strain at the weld induced martensitic phase transformation,and then corrosion microcells were formed with martensite and austenite,leading to local microcell corrosion.[Conclusion]To solve the said spout corrosion problem,the surface quality of the original steel sheet should be improved,and a welding method with less pressure and more uniform force should be used instead of the intensive spot welding process.

关 键 词：奥氏体不锈钢 壶嘴 焊缝 腐蚀 马氏体相变 

分 类 号：TG172[金属学及工艺—金属表面处理]