X80钢级厚壁螺旋缝埋弧焊管导向弯曲不合格原因分析.pdfVIP

26 。茸验与研穷 X80钢级厚壁螺旋缝埋弧焊管导向弯曲不合格原因分析 牛爱军z～，牛 辉 ～，黄晓辉t～，刘海璋 ～，赵红波t，z (1．国家石油天然气管材工程技术研究中心，陕西 宝鸡 721008： 2．宝鸡石油钢管有限责任公司，陕西 宝鸡 721008) 摘 要 ：针对X80钢级 1219mmx22mm大直径厚壁螺旋缝焊管试制过程中连续出现的导向弯曲试验不合 格问题 ，通过化学成分分析、力学性能试验 、显微组织及开裂断El形貌观察等方法，对导向弯曲开裂原因进行了 分析。结果表明：开裂钢管焊接接头热影响区存在明显软化；在断口上多处存在的夹渣和气孔等焊接缺陷诱发了 断裂的裂纹源；弯曲塑性变形引起熔合线附近粗晶区中硬而脆的M／A岛与板条铁素体基体间的界面产生较大的应 力集中，导致弯曲开裂。提出了有针对性的建议。 关键词：厚壁螺旋缝埋弧焊管；X80钢级；导向弯曲试验；气孔 ；夹渣；热影响区；软化；MA／岛 中图分类号：TG115．5 文献标志码：B 文章编号：1001—2311(2015)06—0026-06 AnalysisofCausesforNonconformance ofHeavy—wallX80SAWH PipetoGuideBendingTest NIUAijun一，NIUHui～，HUANGXiaohui～，LIUHaizhang～，ZHAOHongbo’ (1．NationalPetroleumandGasTubularGoodsEngineeringTechnologyResearchCenter，Baoji721008，China； 2．SteelPipeResearchInstitute，BaojiPetroleumSteelPipeCo．，Ltd．，Baoji721008，China) Abstract：Addressingtheproblem offrequentoccurrenceofnonconformanceofthe 1219mmx22mm large— sized， heavy-wallX80 SAWH pipe to theguidebendingtestas identified duringthe trialproduction process， investigation into thecausesforcrackingofthe guidebendingtestspecimen isconducted bymeansofchemical compositionanalysis，mechanicalpropertytesting，andobservationofmicrostruetureandrupturemorphologyofthe specimen，etc．Asaresult，itisfoundthatthesaidspecimen’Scrackingiscausedbythecircumstancesasfollows． ThereexistsobvioussofteningoftheHAZofthepipe’Sweldjoint．A lotofweldingdefectslikeslaginclusionsand porositiesasstayingintheruptureareainducethecracksourceoftherupture．Andthebendingplasticdeformation leadstoremarkablestressconcentration attheinterfacebetweenthehardandbrittleM ／A islandinthecoarsegrain zoueneartheweldbondandthelathferritematrix．Accordingly，relevantsuggestionsareputforward． Keywords：heavy—wallSAWH pipe；St．G．XS0；guidebendingtest；porosity；slaginclusions；HAZ；soften—