废热锅炉的焊缝热处理及泄漏原因分析与修复

316201012RECHULIJISHUYUZHUANGBEIVo.l31,No.6Dec,2010:2010-07-20:(1953-),,:13685562654;E-mai:[e-mail]潮道明(安徽盈创石化检修安装有限责任公司安徽安庆246001):E-406废热锅炉,是安庆石化炼油厂硫磺回收设备之一,三类压力容器锅炉主体的壳体材料为20g26mm钢板,换热管为45mm5mm的20钢管加表面扩散型渗铝经过整体焊后热处理最后管子和壳体的气密性及水压试验完全合格开车几天后,炉管产生严重泄漏打开箱体,发现管口焊缝多处有微裂纹经打磨焊缝发现:管子和管板间角焊缝的根部有未焊透和少量气孔与金属夹杂物,造成局部缝隙高温高压汽体膨胀隔热与泡沫腐蚀而未去除干净的少量渗铝层,在氩弧焊接时有形成焊接气孔金属夹杂物和结晶裂纹的倾向,以及出口尾气中H2SSO2等气体腐蚀而加速管子和管板间焊缝的开裂经现场打磨并重新采用电弧焊接修复后,使用至今一年多,一切工况正常完好:废热锅炉;焊缝;泄漏;修复:TG404:A:1673-4971(2010)06-0059-06HeatTreatmentofWeldedSeamandAnalysisandRepairofLeakageaboutWasteHeatBoilerCHAODaoming(AnhuiYingchuangPetrochemicalMaintenanceandInstallationCo.,Ltd.,AnqingAnhui246001,Chuna)Abstract:E406wasteheatboilersisoneofsulfurrecoveryequipmen,tthethirdtypeofpressurevesse,linAnqingPetrochemicalRefinery.Theheatexchangepipeis20steelpipe(45mm5mm),andthematerialofboilerbody(shell)is20g26mmsteelplatewhichisaluminiziedwithdiffusiontypeinsurface,andisheattreatedafterwholewelding.Finally,airtightnesstestingandhydraulicpressuretestingarefullyqualified.Runningafewdayslaterthefurnacetubecausesseriousleakage.Openingthecabine,ttherearemanymicrocracksatthenozzleofweldseam.Polishedweldseam,therearepartofnotweldingfullyandsmallamountofmetalinclusionsandairholesatangularweldseambetweentubeandplate,bringaboutinsulationexpansionandfoamcorrosionofhighpressureandhightemperaturevaporinthelocalaperture.Therearethetendencyofformingweldingairholes,metalinclusionsandcrystalcracksinnotcleanedsmallamountofaluminizinglayerwhenTIGwelding,aswellastheweldseamsarecorrodedbyH2S,SO2etcintailgasofexpor,ttoacceleratecrackingofweldseambetweentubeandshee.tTheboilerhavebeenallconditionnormalintactafterrepairedbyonsiteburnishingandarcweldingagainformorethanoneyear.Keywords:wasteheatboilers;weldseam;leakage;repaire310E40620088;,,,,,;,,;,;,,,1E4061.11Fig.1Structureofwasteheatboilerdrum1,1.220g,20,20(1)1.31Table1Size,compositionandperformanceofthemainbodymaterialofwasteheatboilerdrum()%CMnSiSPRm/MPaRel/MPaA/%/!(V)/J/∀/mm20g=26mm0.170.630.220.0080.01044529532.5201741601821801.5a20g=16mm0.170.600.200.0200.01346031031.501841941901801.5a20g=22mm0.190.650.250.0090.01846528533.5202281561921801.5a2045mm5mm0.180.520.230.0130.01746030032.0----20=26mm0.200.640.350.0200.01549529527201161661401802a1.3.1(2)2Table2Designparamenersofwasteheatboilerdrum/MPa2.00.1/!220380/mm1.5311H2SSO2H2OH2O2Co1.3.2H2SSO2H2OH2O2Co,,,20,3606:320Table3Diffusionaluminizedlayerparametersof20steelpipe/mm0.19~0.237~8/HV0.18708508351.3.3(4)4#∃4Table4Mechanicalpropertiesofsteelpipebeforeandafterdiffusionaluminized/MPa/MPa/%1-1525355322-147033531.52Fig.2Photoofaluminizedlayer3Fig.3Microstructureofgrassrootsorganizations23#∃22.1AB4(AC),+C1(D)*D1B,D2D,5*D1,2.2,4Fig.4Schematicdrawingofgrooveformpressuredweldseamofbolilerdrumbody61315Table5Weldingparametersofthemainweldedseamofwasteheatboilerdrum/mmAVAB20g=26SMAWSAWJ427J427H08A/HJ4313.244DCRP90~110145~170500~65020~2620~2632~38100%RT%C120g=22SMAWJ427J4273.24DCRP90~110145~17020~2620~26100%MT&*D120g53030/26SMAWJ427J4273.24DCRP90~110145~17020~2620~26100%MT&D220/20g455/22GTAWH08MnA2.5DCSP80~11010~20100%PT&+,,5mm2.3100%RT%,95%,;100%MT&;100%PT&,33.15m20m3.25Fig.5Heattreatmentcurveofdrumafteroverallwelding6Table6Heattreatmentprocessparametersofdrumafteralloverwelding/mm(V)/!h-1/!/h(V)/!h-1/HB20g26400!∋150620(102∋200400!∋2003.3(7)42.5MPa0.1Mpa,,,,:(8)55.120088E-406,,66Fig.6Diagramofweldedseamdefectatleakagenozzle626:7Table7MechanicalpropertiesofweldingtestplateofdrumafteroverallheattreatmentRM/MPaREL/MPaA/%Akv/!J/HB/∀45527031.0201101121061441501551804a8Table8DataandconclusionsofdrumpipeshelltightnessandhydaulicpressuretestP/MPa/MPamin-1//!2.5MPa2.5/302.0/3033/250.1MPa0.1/300.08/3030/24-0.1MPa0.1/3028/280.1MPa0.1/3022/22-;:(1),,(2);(Al2O3),,(3.85g/cm3)(2.6~2.8g/cm3),;,,[1][2],(3),[3](4)[4][5]:220!,380!;2.0MPa;:1.5mm,,,,;:(5):380!,0.1MPa;3mm;(),H2SSO2H2OH2O2Co:H2S+O)H2O+S∗,SO2+H2O)H2SO4,;,,(6),,(S)(7),,,.(8)2m,22mm26mm,70045+0.5,14-0.5mm;,:380-220=160!,:2.0MPa-0.1MPa=1.9MPa700,,,;∋160!∋1.9MPa,,,,5.2,,;,,700,J4273.2mm,2.5MPa63310.1MPa,6(1)E-406:+,,,−H2S,SO2,.,,/(2):+6mm;,,,−J4272.5mm3.2mm,,25mm2.5mm,1.6().30∀;()/(600(10)!,2h0,;:+,;,[1].,12,,1997.5.528.[2]..,1989.[3].().,2006.[4].[],1988.[5].H1201[J].,2008,29(2):74-78.[6].20#.,1995.(上接第58页)320084,,,:(1)(2)1%(3)(4)312500,32500(),(5):(5!,(5!,(5!(6),,42008420105,31.78,10.36,2008,,60%,8000,20091700,89%2009,100,100%,,,,[1].[J].,2006,28(3):12.64