钢板表面纵向裂纹的金相检验和分析

PTCA(PART:APHYS.TEST.)20064212,,,(,115005):在连铸轧制的钢板表面有沿轧制方向的裂纹采用化学成分分析,宏微观检验等方法对裂纹进行了分析结果表明,裂纹中存在氧化物及其脱碳等缺陷,这说明连铸坯表面在轧制前已存在裂纹并在轧前加热中裂纹内发生氧化和脱碳,导致轧制后的钢板表面出现裂纹:表面纵裂;金相检验;连铸板坯:TG335.5:A:10014012(2006)12063403METALLOGRAPHICALEXAMINATIONANDANALYSISOFLONGITUDINALCRACKONSTEELPLATEXUQingtai,WEIBo,ZHAOXiaofei,SUNWei(MinmetalsYingkouMediumPlateCO.Ltd.,Yingkou115005,China)Abstract:Therearesomelongitudinalsurfacecracksappearonthecontinuouscastingslabandconsequentlyontherollingsteelplate.Bymeansofthechemicalcompositionanalysis,macroscopicobservationandmicrostructureexamination,theresultsshowedthatthereisoxideinthecrack,andthedecarburizingandthepitoxideareexsitedinthecontinuouscastingandrollingprocess.Allthesefactorscausedthelongitudinalsurfacecracksappearedonthesteelplateafterrolling.Keywords:Thelongitudinalsurfacecarcks;Metallographicalexamination;Continuouscastingslab1Q235B,():250mm1500mm,1546300.9m/min100mm130mm22.1,1/420~1500mm,0.5~5mm(100~160mm),;(12~22mm),:20060314:(1937-),,,,;,60%,12.2,,,,23,();1.2mm,0.75mm,,(a)100mm1634许庆太等:钢板表面纵向裂纹的金相检验和分析(b)130mm11()Fig.1Theappearanceofsurfacelongitudinalcracksofdifferentthicknesssteelplate2()40Fig.2Theappearanceofoxideincrackanddecarburizingaroundthe(crosssection)crackonthesurfaceofthicksteelplate2.3,():0.143%C,0.203%Si,0.53%Mn,0.020%P0.009%S,():13.26%O,4.35%Si,10.73%Mn71.66%Fe3[1,2],,,,,:(700~800);,COCO2,,,950~1200,(a)400(b)1003()Fig.3Theappearanceofthepitoxidearoundthecracksinsurfaceofthethicksteelplate(crosssectun)0.5h,(Fe,Mn)OSiO2[2],0.05%,,0.25%,0.203%,[3],,,,(12~22mm),,,,,,635PTCA(PART:APHYS.TEST.)20064212(,200437)::A:10014012(2006)12063601CONTENTSOFNATIONALANDINDUSTRYSTANDARDINCURRENTEDITIONQJ2136.3-1991QJ2337-1992SJ/Z330-1972TB/T2576-1995TB/T2786-1997TB/T2787-1997TB/T2816.1-1997TB/T2816.2-1997TB/T2908-1998TB/T3031-2002YB/T153-1999YB/T169-2000YB/T4002-1991YB/T4003-1997YB/T4052-1991YS/T335-1994YS/T370-2006YS/T448-2002YS/T449-2002,,,,[4],,,,,,4,,:,Q235B,(),;,:[1].[M].:,2000,6:150-154.[2].[M].:,1989.206-210.[3].[J].,2003,(3):27-29.[4].[M].:,1994,12:310-320.[5].[J].,2005,(1):37-38.636