1、UDC 669标准分享站National Standard of the Peoples Republic of ChinaGB/T704-88Dimensions,shape,weight andtolerances for hot-rolled flats1 ssued on1988-02-05Effected on 1989-02-01Issued by National Administration of Standard标准分享站National Standard of the Peoples Republic of ChinaUDC669.14Dimensions,shape,we
2、ight andGB/T704-88tolerances for hot-rolled flatsSuperseding GB 704-83This standard is applied to the hot-rolled flats with a thickness of 360 mm,a width 10150 mm and arectangular section used for general purpose.1 Dimension and tolerances1.1 The section and marking symbols of flat are shown as figu
3、re 1:Fig.1t-Thickness of flat;b-Width of flat1.2 The section dimension and theoretical weight of the flat should meet the stipulation of table 1.According to the requirement of customer and agreement of both sides of supplier and customer,theflats with other dimension between the sizes listed in tab
4、le 1 can be supplied,and their tolerances should bebased on that specified for one of the abutting flats with biggish dimension.1.3 The tolerances for section dimension of flat should meet the stipulation of table 2.Table2mmWidthThicknessTolerancesTolerancesDimensionDimensionGeneral classHigher clas
5、sGeneral classHigher class+0.5+0.310-50-1.0-0.9+0.3+0.2316+0.6+0.4-0.5-0.450-75-1.3-1.2+0.9+0.775-100-1.8-1.7+1.5%+1.0%1660+1.0%+0.8%-3.0%-2.5%100150-2.0%-1.8%The thickness difference measured between any two points at same section should not exceed 50%of thethickness tolerance.Authorized by ministr
6、y of metallurgical industryof the Peoples Republic of China 1988-01-18Effected on 1989-02-01标准分享站GB/T704-88品四8一9621761086218696660602158-0-169w/ayILP0666829290N08066一e一80导+的0102763Tog#I4t=692z0c二一K一0一o2 t6626226N子9一#一一69,6360830四一3一#一5269299060四一#一5N009900-81一四#一一2一96925800930360二一四一5一8069.001806080
7、8090N001四一号品2标准分享站GB/T704-882 Length and tolerance2.1 Usual length2.1.1 Ordinary steelFlat group 1(theoretical weight19 kg/m)3-9mFlat group 2(theoretical weight 19 kg/m).37m2.1.2 High grade steelThe flat of all sizes26mBased on the agreement of both sides of supplier and customer and the explanatory
8、 notes in contract,the flat with over-long length can be supplied.2.2 The length with fixed dimension or multiple fixed dimension and the tolerances2.2.1 clearly should be noted clearly in contract.2.2.2 The length tolerance of the flat with the length of fixed dimension or multiple fixed dimensions
9、hould meet following stipulations:Length4 m+300mmLength46+50m0mmLength6 m+700mm3 Shape3.1 CamberThe camber of flat should meet the stipulations of table 3.Table 3mmCambernot exceedAccuracy classCamber per meterOverall camberGeneral class40.4%of the goods deliveredHigher class2.50.25%of the goods del
10、ivered3.2 TorsionFlats should not exist obvious torsion.3.3 Shear dragFlat ends should be sheared straight,the shear drag should not exceed following specified:Should not exceed 6 mm for the flats with a width100 mm;Should not exceed 8 mm for the flats with a width100 mm.3.4 Deviant of the cross sec
11、tional shapeThe deviant of the cross sectional shapes are shown as figure 2(a),(b),(c),(d),their max acceptabledimension(value C)should meet the specified of table 4.Table 4mmFlat thicknessMax acceptable dimension(value C)5I5-1020%of thickness1015%of thickness,the max value is 3.54标准分享站GB/T704-88(c)
12、dFig.24 Weight4.1 The flat with usual length will be delivered based on actual weight.By the agreement of both sidesof supplier and customer and the explanatory notes in contract,it can be delivered based on the theoreticalweight.4.2 The flat with the length of fixed dimension or multiple fixed dime
13、nsion will be delivered based onthe theoretical weight.By the agreement of both sides of supplier and customer and the explanatory notes incontract,it can be delivered based on the actual weight.5 condition of deliveryFlats are delivered as straight bars.6 Example of mark symbolThe mark symbol for the flats rolled with the steel grade 45 and with the dimension of 10 mm 30 mmshould be:Flat1030-GB704-8845-GB699-88Postscript:The draft of this standard was presided over by Shanghai the Eighth Steel Plant.The main drafters of this standard is Du Yiyi
