ASTM_A_726-18.pdf

A726-183.Terminology5.1.1 ASTM specification number and date of issue.3.1 Definitions-See Terminology A340.5.1.2 Core-loss type number.5.1.3 Surface texture(indicate typical profilometer range,as3.2 Definitions of Terms Specific to This Standard:required)(see 11.2).3.2.1 cold-rolled sheet-sheet manufactured from hot-rolled5.1.4 Specify not oiled or oiled,as required(see 11.4).descaled coils by cold reducing to the desired thickness,5.1.5 Dimensions(nominal thickness and coil width)andgenerally followed by annealing to recrystallize the graintolerances,if not standard(see 10.1).structure.In the case of magnetic lamination steels,particularly5.1.6 Coil size(must include limitations on inside diametersemiprocessed lamination steels,temper rolling is used afterand maximum weight).annealing to enhance flatness and optimize magnetic properties5.1.7 Application(the user shall disclose as much pertinentduring the users lamination anneal.information as possible about the intended application to3.2.2 magnetic lamination steels-specialty cold-rolled car-enable the producer to provide material characteristics mostbon sheet steel melted to controlled levels of carbon withsuitable for specific fabricating practices).additions of manganese,phosphorus,silicon,and aluminum.5.1.8 Special requirements or exceptions to the provisionsResidual elements are generally held as low as possible.Theof this specification.appropriate chemical composition combined with controlled5.1.9 Cast or heat analysis and magnetic test report(requestmill processing results in a carbon sheet steel having mechani-if required).cal properties and magnetic properties(after a quality devel-opment anneal)desired for electrical applications.NorE 1-A typical description is as follows:Cold-Rolled Sheet.Magnetic Lamination Steel,ASTM A726 64D480.Surface Roughness4.Classification1.3-to 2.0-um(50-to 80-uin.)arithmetic average(R).Not Oiled,0.64 by1245 mm(0.025 by 49 in.)by coil.610-mm(24-in.)inside diameter.90004.1 The cold-rolled magnetic lamination steel types de-kg(20 000 Ib)maximum,for fractional horsepower motors.scribed by this specification are shown in Table 1.6.Materials and Manufacture5.Ordering Information6.1 Melting Practice-These steels are typically made by5.1 Orders for material under this specification shall includethe basic-oxygen or electric-furnace process.the following information,as required,to describe the required6.1.1 These steels are characterized by low carbon,usuallymaterial adequately:less than 0.060%For higher quality core-loss types,theTABLE 1 Core-Loss Types and Maximum Specific Core-Loss Values at 1.5 T(15 Kilogauss)and 60 HzNorE 1-Specific core-loss values are developed after quality development anneal(QDA)per the recommended practices in 13.3 of this specificationEpstein test specimens(with one half cut parallel and the other half cut perpendicular to the direction of rolling).NorE 2-Maximum specific core-loss values at 50 Hz are 0.79 x maximum core-loss values at 60 Hz.SheetCore-MaximumMaximumThickness.LossCore LossCore Loss,mm(in.)TypeW/kgw/Ib0.36(0.0140j36D1453.201.4536D1553.421.550.47(0.018547D1653.6447D1753.8647D1904.191.9047D215692.1547D2702.7047D33047D380880.56(0.022)56D2305.072.3056D2602.6056D3103.1056D3803.8056D4404.400.64(0.025)64D26064D29028964D36064D43064D49010.84.900.71(0.028)71D4109.041071D48071D55019680.79(0.031)79D4509.924.5079D54011.95.4079D61013.56.104A726-18carbon content is typically less than 0.04 and may bebusted natural gas atmosphere with suitable dew point is oftenreduced to less than 0.02%by means of vacuum degassingused.Also,some users of lamination steels use a hydrogen-argon stirring.or other steel refining practices when suchnitrogen gas mixture with a suitable dew point.For steellow-carbon contents are required to facilitate decarburizingcontaining manganese,silicon,and aluminum.annealing con-during annealing.Some magnetic lamination steels are pro-ditions shall be such that subsurface oxidation of these ele-duced to carbon contents less than 0.005%.In these steels.ments is minimized.decarburization during annealing may not be required.Theprinciple alloying element is commonly silicon,but aluminum7.2 Specific Core Loss-Each core loss type is identified byup to about 0.8 is sometimes used instead of,or in additionmaximum specific core-loss limits as shown in Table 1.to silicon.depending on mill processing practice for the desired7.3 Permeability-The permeability at all magnetic fluxmagnetic grade.Individual producers will often have differentdensity levels shall be as high as possible consistent with thesilicon or aluminum contents for a particular grade as a resultrequired maximum specific core-loss limits that govern theof intrinsic mill processing procedures.Manganese or phos-phorus may also be added to enhance punchability and improvegrade.The typical values of relative peak permeability forhigher quality core-loss types are given in Appendix X1.magnetic characteristics.6.1.2 Residual elements found in steels are generally held as8.Surface Insulation Characteristicslow as practical.6.1.3 In the past,the alloy additions to magnetic lamination8.1 Unless otherwise specified,cold-rolled magnetic lami-steels have been restricted such that the density of the steel wasnation steels are supplied with no mill-applied coating.Amaintained above 7825 kg/m(7.825 g/cm).However,higheruser-formed oxide(coating Type C-1 in Classification A976)quality core-loss type magnetic lamination steels may havecan be created at the end of the heat treating cycle and providesalloy contents with density values less than 7825 kg/m3(7.825adequate insulation for most applications.g/cm)and subsequent testing for magnetic properties shall bein accordance with the procedure of Test Method A343/8.2 Applied Coatings:A343M(see Section 12)8.2.1 Several types of thin,tightly adherent applied coatings6.1.4 The producer is not required to report chemicalcan be applied to magnetic lamination steels.If a coating willcomposition of each lot except where a clear need for suchbe applied,the surface finish(see 10.2)may be altered toinformation has been shown.In such cases,the analyses to beensure proper insulating characteristics and coating adherence.reported shall be negotiated between the producer and user.Most suitable for magnetic lamination steels are coatings6.2 Typical Rolling and Annealing-The processing se-designed to withstand the heat treatment performed afterquence for magnetic lamination steel comprises hot rolling.stamping(coating Type C-5 in Classification A976).pickling.cold rolling,annealing.and temper rolling.An8.2.2 The use of coatings as specified in Classificationadditional annealing operation may precede or follow theA976,or other coatings.as well as the test method(Testpickling operation.Methods A717/A717M or A937/A937M).minimum value of6.2.1 Magnetic lamination steels(all types)are cold reducedinsulating ability and other conditions for evaluating theto thickness and are usually temper rolled after box oreffectiveness of the coating,shall be determined by agreementcontinuous annealing to enhance magnetic property develop-between the user and producer.Usage of such coatings shouldment during the users lamination anneal.In addition,thebe approached with great caution since the coatings may havetemper pass is used to improve sheet flatness and punchabilityan inhibiting effect on decarburization and thereby limit theand to obtain the required surface texture.Special emphasisattainment of the lowest specific core losses in the users heatmay be placed on high extensions(2 to 10%)during thetreatment.temper roll after annealing.6.2.2 When changes in the manufacture of the material are9.Mechanical Propertiesbelieved to exert possible significant effects upon the usersfabricating practices and upon the magnetic performance to be9.1 Hardness in the finished product depends on chemicalobtained in the specified end use,the producer shall notify thecomposition and mill processing.For the mill process annealeduser before shipment is made so that user has an opportunity toand temper rolled condition,hardness values typically rangeevaluate the effects.from Rockwell 45 to 85 HRB9.2 Specific ranges of hardness are subject to negotiation7.Magnetic Property Requirementsand should be specified on the order.7.1 The magnetic properties of these steels are optimized9.3 Rockwell hardness measurements are normally deter-when the stamped laminations or assembled core structures aremined by a superficial test(R30T and R15T)and converted toannealed to reduce the carbon content to 0.005 or less.Toa B scale value in accordance with Test Methods E18 andavoid sticking of laminations and assure adequateTables E140.decarburization.the annealing temperature should be in therange from 730 to 845C(1350 to 1500F).Time at tempera-9.4 When mechanical tests are required,test specimensture will vary with lamination dimensions,charge size,surfaceshall be prepared and mechanical tests conducted in accor-finish,and annealing furnace characteristics.A partially com-dance with Test Methods and Definitions A370.A726-1810.Dimensions and Permissible Variationspromote decarburization and minimize sticking during the10.1 Tolerances for thickness,width,and camber applicablelamination anneal.Depending upon the applicationto magnetic lamination steels are shown in Table 2.Table 3.requirements,surface roughness is usually within the rangeand Table 4.from 1.0-to 4.0-um(40-to 160-uin.)arithmetic average(R)at 0.76-mm(0.030-in.)cutoff and 3.2-mm/s(0.125-in./s)trac-10.2 Thickness Variations-The average thickness of theing speed and a minimum 25-mm(1-in.)stroke.material supplied shall be as close as possible to the orderthickness.Measurements made with a contacting micrometer11.3 Cut edges made at the continuous pickler before coldat points no closer than 10 mm(0.375 in.)from the edge of areduction(non-side trimmed last)will be furnished unlesssheet or coil of specified width shall not differ from theotherwise specified.specified thickness by more than the value(which includes11.4 Magnetic lamination steel is customarily furnished nottaper)shown in Table 2.oiled(dry).If it is to be oiled,it must be so specified.10.3 Taper-The rolling of flat rolled sheets inherentlyproduces an edge which is thinner than the rest of the sheet12.SamplingThis characteristic is termed tapered edge or feather or gamma12.1 Tests for magnetic properties,when required,shall beand occurs primarily within 25 or 50 mm(I or 2 in.)from thetaken in a manner to assure representative sampling of the testas-rolled edge of the material.The thickness variation,classi-lot.For quality control purposes,a test lot comprises one heatfied as edge taper,is often the major portion of the total overalland it is usual practice to sample one coil from a cast or heatthickness variation permitted in 10.2.It may be expected thatFrequency of sampling when magnetic properties are guaran-in the case of edge slit coils,the following limits on theteed shall be subject to negotiation.differences in thickness measured within the first 50 mm(2 in.)or less from either edge of the ordered width will apply:13.Test MethodsOrdered ThicknessMaximum Taper13.1 Tests shall be conducted for magnetic properties inmm(in.)mm(in.)accordance with the procedure of Test Method A343/A343M.0.36(0.014)0.025(0.0010)0.47(0.01850.030(0.0012)13.2 Prepare test specimens from lengths cut from one or0.56(0.0220.035(0.0014)both ends of a coil with one half of the specimens cut parallel0.64(0.0250.0350.00141and the other half perpendicular to the direction of rolling.Over0.71(0.028)0.040(0.0016)More restricted cross-width thickness tolerances may be13.3 For quality control purposes and grading in accordancenegotiated between the producer and the user.with maximum core-loss specifications,give the specimenstrips to be tested a controlled quality development anneal10.4 Because of the special processing treatments used for(QDA)in a decarburizing atmosphere.The anneal shall bethese steels,ordinary flattening operations used for other steelmade under conditions that ensure that the specimen stripsproducts may not be used due to their effects on magneticreach a temperature of 790C(1450F)for approximately 1 hproperties.Special flatness requirements for a particular appli-and with conditions favorable to decarburization.For alloycation should be made known on the purchase order.contents greater than 1.3%silicon plus aluminum,the tem-perature may be 845C(1550F),or as agreed upon by11.Workmanship,Finish,and Appearanceproducer and user.The atmosphere shall contain sufficient11.1 The steel shall have a workmanlike appearance andmoisture to be highly decarburizing but should not excessivelyshall be reasonably free of imperfections of a nature or degreeoxidize the specimens.In some cases,other annealingthat will be detrimental to the fabrication of the finishedpractices,such as non-decarburizing or alternate temperatureslamination.Coils may contain some abnormal imperfectionsmay be negotiated by user and producer.Further informationwhich render a portion of the coil unusable because theon annealing atmosphere selection and objectives can be foundinspection of coils does not afford the producer an opportunityin Appendix X2.Take care to maintain the strips flat in theto remove portions containing imperfections.anneal and permit ready access of the atmosphere to the edges11.2 Magnetic lamination steel is supplied with a surfaceof the specimen strips.texture produced by rolling on mill rolls which have been13.4 As described in Practice A34/A34M.Section 10roughened by mechanical,chemical,or electrical means tocalculate the assumed density for test purposes from the steelvarious degrees of surface texture.The roughened textureschemical composition as follows:TABLE 2 Thickness Tolerances,Cold-Rolled Sheet,Magnetic LaminationSteel for Specified Width 50 to 1520 mm(2 to 60 in.)InclusiveSpecifiedThickness Tolerance,ThicknessOver and Undermm(n)mm(in.)over 0.48 to 0.99 incl(over 0.019 to 0.039.incl)0.08(0.003over 0.36 to 0.48 incl(over 0.014 to 0.019,incl)0.05(10.002)A Thickness is measured at any point across the width not less than 10 mm(in.)from a side edge.4A726-18TABLE 3 Width Tolerances,Cold-Rolled Sheet,Magnetic Lamination SteelWidth ToleranceSpecified WidthOverUndermmmm(n.)mm(in.)50 to 150,incl(2 to 6.incl)0.20(0.008)0.20(0.008)over 150 to 230,incl(Over 6 to 9.incl)0.41(0.016)0.41(0.016)over 230 to 300,incl(Over 9 to 12.incl)0.81(0.0320.81(0.032over 300 to 760.incl(Over 12 to 30.incl)32(0.125)0over 760 to 1220,inclOver 30 to 48,incl)4.8(0.188)0over 1220 to 1520,incl(Over 48 to 60,incl)6.40.250100Width tolerances for 0 to300mm(2to 12 in.)inclusive apply to widths produced by sliting from wider sheet coils.TABLE 4 Camber Tolerances,Cold-Rolled Sheet,Magnetic Lamination SteelCoil WidthCamber Tolerancemm(in.)50 to 300,incl(2 to 12.incl)6.4 mm to any 2.4 m(%in.toay8间over 300 to 1250.incl(Over 12 to 60.incl)25 mm to any 6.1 m(1 in.to any 20 ft)Camber is the greatest deviation of a side edge from a straight ine,the measurement being taken on the concave side with a straight edge.6 The tolerance of 50-to 300-mm(2-to 12-in.)inclusive widths applies to those coils slit from wider sheet coils.(%Si+1.7%A0Assumed Test Density15.2 As a minimum requirement,the material shall bekg/m3(g/cm)identified by having the producers order number and material0.00-0.627850(7.85)identification legibly shown on a tag attached to each coil or0.63-1.387800(7.80)shipping unit.1.39-2.157750(7.752.16-2.927700(7.70)2.93-3.697650(7.65)16.Rejection and Rehearing14.Certification16.1 Material that fails to conform to the requirements of14.1 The producer shall submit to the user,as promptly asthis specification may be rejected by the user.The rejectionpossible after shipment,a certified report of the averageshall be reported to the producer promptly and in writing.Thespecific core-loss values or any other required test values,forreject material shall be set aside,adequately protected,andeach test lot,to show that the material conforms to thiscorrectly identified.specification.16.2 The producer may make claim for a rehearing.In this14.2 The test methods and applicable test conditions,inevent,the user shall make samples that are representative of thecluding the test density,shall be clearly stated.rejected material available to the producer for evaluation.14.3 The test report shall carry the lot identification,pur-chase order number,and other information that is deemed17.Keywordsnecessary to identify the test results with the proper shipment17.1 carbon steel sheet:cold-rolled magnetic laminationand shipping lot.steel;lamination steel;semiprocessed15.Packaging and Package Marking15.1 Unless otherwise specified,the steel shall be packagedand loaded in accordance with Practices A700.5