钢球表面裂纹正反方向处的异常漏磁场

(,210037):,,,(180):;;;:TG115.28:A:100026656(2003)0820407203ABNORMALMAGNETICLEAKAGEFIELDOVERTHESTEELBALLSURFACEWITHCRACKANDITSOPPOSITEZHONGWei2chang(NanjingGasTurbineResearchInstitute,Nanjing210037,China)Abstract:Onthebasisofthefactthattherearealwayssmallpeaksandvalleysonmachinedsurfaces,theexperimen2talresultsofdetectingthecrackonasteelballsurfacehavebeenexplainedbymagneticdipoletheoryasthatthemagneticleakagefieldstrengthoverasteelballsurfaceishigherthanthebackgroundofthegeomagneticfieldthere;themagneticleakagefieldstrengthoverthesurfacecrackishigherthanthatoverthesmoothballsurface;onthecontrary,themagnet2icleakagefieldovertheballsurfacewithcrackanditsopposite(180)arelowerthanthebackgroundofthegeomagneticfield.Keywords:Electromagnetictesting;Magneticfield;Steelball;Crack[1],,1[1],310-5T3.7510-5T,(3.73.8)10-5T(4.24.8)10-5T[1],:2002208212:(50001006),(180),,7.610-6T,[1](36)10-5T,,,,2()[2]:(1),,,,(2),,70425820038NDTVol.25No.8Aug.2003©1995-2004TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.(3),()[3,4](4),,,,,,[2]3[57],,(1a),(1b)(a)(b)1[8,9],,(2)2,,(),,(3),,34,,(4)[10],()4[10]4,He,Hl,HlHe,(5a),HH=He+Hl(1)HHe(2),Hl[1],He=310-5T,H=(3.73.8)10-5T(a)Hl(b)Hs804:©1995-2004TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.,,Hs(5b)Hl,HsHl(3)[1]Hl+He=(3.73.8)10-5THs+He=(4.24.8)10-5T5(5a)[2](),(5b),,,,(180)(5c)[11,12],H¨,H¨HeHl(5c),HH=He+Hl-H¨(4),,[12],H¨,HHe(5)[1],H=7.610-6T6(1)(2)(3)(180),,(4)(180):[1],.[J].,2001,23(8):330-333.[2],.[M].:,1978.[3].[M].:,1985.[4],.[M].:,1987.[5].[J].,2000,22(3):116-118.[6].[J].,1997,19(4):95-98.[7]Wei2ChangZhong.Theoreticalfundamentalsofmagneticdipoleforlongitudinalmagnetizationofasquaresteelcomponent[J].MaterialsEvaluation,1999,57(9):937-939.[8].[A].MT,PT()[C].:1996.[9]Wei2ChangZhong.Non2relevantmagneticparticleindi2cationsalongthebaseapexlinesofworkpiecesmagne2tizedcircumferentiallyprincipleofMPI[A].Pro2ceedingsof10thA2PCNDT[M/CD].BrisbaneAustrali2a:2001.[10].[M].2,:,1996.[11].[A].[C].:2002.248-254.[12].[A].[M/CD].:2003.2003,,42237,13904:©1995-2004TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.