■■■■■■■■■■■■■■失效分析DOI:10.11973/fsyfh-202302016不锈钢换热管泄漏失效的原因刘海波1,王君2,王安友1,徐鑫1,沈赵琴1,蒋达磊1(1.浙江国检检测技术股份有限公司,海盐314300;2.海盐县三地自来水有限公司,海盐314300)摘要:某化工企业多台管壳式换热器在服役3~4a后陆续发生泄漏,拆卸后检查发现换热器内部大量304不锈钢换热管存在开裂或穿孔现象。通过宏观形貌分析,扫描电镜及能谱分析,金相检测,化学成分分析、晶间腐蚀试验、残余应力测试等手段对不锈钢管失效原因进行分析。结果表明:换热管出现穿孔和开裂失效的主要原因是材料发生了晶间腐蚀及应力腐蚀。换热管材料304不锈钢具有晶间腐蚀敏感性,换热管内外壁都存在明显的残余拉应力,且介质中存在S、Cl等腐蚀性元素,换热管材料同时具备以上3种应力腐蚀开裂的必要条件而发生应力腐蚀开裂。关键词:304不锈钢管;孔洞;裂纹;晶间腐蚀;应力腐蚀中图分类号:TG172文献标志码:B文章编号:1005-748X(2023)02-0094-07ReasonsforLeakageFailureofStainlessSteelHeatExchangeTubesLIUHaibo1,WANGJun2,WANGAnyou1,XUXin1,SHENZhaoqin1,JIANGDalei1(1.ZhejiangNationalInspectionandTestingTechnologyCo.,Ltd.,Haiyan314300,China;2.HaiyanSandiCityWaterCo.,Ltd.,Haiyan314300,China)Abstract:Anumberofshellandtubeheatexchangersinachemicalenterpriseleakedoneafteranotherafter3-4yearsofservice.Afterdisassembly,alargenumberof304stainlesssteelheatexchangetubeswerefoundtobecrackedorperforated.Thefailurereasonsofstainlesssteeltubeswereanalyzedbymeansofmacroscopicmorphologyanalysis,scanningelectronmicroscopyandenergyspectrumanalysis,metallographicexamination,chemicalcompositionanalysis,intergranularcorrosiontestandresidualstressmeasurement.Theresultsshowedthatintergranularcorrosionandstresscorrosionwerethemainreasonsforthecrackingandperforationoftheheatexchangetubes.Theheatexchangetubematerial304stainlesssteelwassensitivetointergranularcorrosion.Therewasobviousresidualtensilestressonboththeinnerandouterwallsoftheheatexchangetubes.AndtherewerecorrosiveelementssuchasSandClinthemedium.Stresscorrosioncrackinghappenedintheheatexchangetubematerialduetothecoexistanceoftheabovethreenecessaryconditionsforstresscorrosioncrackingat...
