DIN7527-Steel-Forgings-Machining-Allowances-and-Permissible-Variations-for-Open-die-Forged-Bars

Dc62823822.2-04.19February 197Steel Forgings弧wMachining Allowances and Permissible Variationsfor Open-die Forged Bars7527Part 6Schmiedestuicke aus Stahl;BearbeitungeoagosciestabechunceDimensions in mm1.ScopeThis Standard applies to open-die forged bars which have had their finel shape imparted to themby hammers or presses.It applies to round,8 teel including tooi】square,hexagonal and octagonel bars:ss well as to flat bars of bigh-gradetosteel and high speed steel with a width-to-thickness ratio smaller than or8 1,and also to flat bars of ordinary low carbon steel and quality steel having awidth-to-thickness ratio smaller than or equal to 5:1.otoinimhed dimeaniom of 1000 thiokem o vid ad2.Dimensions and croaa-sectional shapes2:1:D1nen1n8:The dimensions of open-die forged bars are thickness,vidth and length.In the case of round barsthediameter counts as the thickness,whilst in the case ofthe thick四eBs主s taken as the distance betweensquare,hexagonal and octaconal baretheparallel side faces.In the case of flst barsthe thickness is taken as the smaller distance and the width as the largerparallel side faces.、distance between the2.2.Cross-sectional_shapesABDRound barSquare barOctagonal barFlat barLengthfor all cross-sectional shapes4fq.f2,fs,lr.finished dimensions8,82,83,ls.forging dimensionsmachining allowance:3.Machining allovances and permissible variations3.1-Machining_allovances_and_persisaible_dimension_variationsThese are given in Table 1.Except for the thickness of flat bars,the criteria for determining machining allowances andpermissible variations for lengths and cross-sectional dimensions arecerned.·“the nominal dimenaions conMachining allovances and permissible variations for the thickness of flat bars are to be calcu-lated on the basis of a reference dimension derived from half the(arithmetic mean).The reference dimension calculated in this waysum of"width plus thickness"or with 81 or 2 in Table 1,depending on whether the machining aliovanceeangugeedisior2tions are derived from the finished dimensions or the forging dimensions.2+3色5，orf2or2ge1or2inab1e123Continued on pages 2 to 4Explanations on page 3270