DIN-2391-1-1994

DIN*EN6LISH2391*PT*194■27944460038551B04■DEUTSCHE NORMSeptember 1994Seamless precision steel tubesDINDimensions2391Part 11cS23.040.10Supersedes July 1981Descriptors:Tube,steel tube,precision tube,dimensions.edition.Nahtlose Prazisionsstahlrohre mit besonderer MaBgenauigkeit;MaBeIn keeping with current practice in standards published by the International Organization for Standardization (SO),acomma has been used throughout as the decimal marker.Dimensions in mm1Scope and field of applicationThe limit deviations for diameters given in table 2 allow forThis standard specifies dimensions for cold finished.ovality and apply for the cold finished (hard)(BK)and coldseamless precision steel tubes and is to be used in con-finished(soft)(BKW)conditions.junction with DIN 2391 Part 2 which states the relevantFor heat treated tubes,i.e.cold finished and stress-relieftechnical dellvery conditions.The preferred sizes listed inannealed (BKS),annealed (GBK)or normalized (NBK)table 2 are mainly used in mechanical and automotive en-tubes,the limit deviations for the diameter increase as apinous reuon-ewgineering.function of the wall thickness/diameter ratio (see table 1).Where steel tubes of dimenslons apocificd in this standardThe dimensions given in table 1 also apply to the insideare to comply with the technical delivery conditions listeddiameter of steel tubes.in subclause 1.2 of DIN 2391 Part 2,they shall be orderedIn the case of intermediate sizes,the deviations for the nextin quality grade C.largest size shall apply.The limit deviations for wall thickness shall be t10%of the2Dimensionsnominal size and include the concentricity tolerance.whichis calculated as a percentage using the following formula:The tube diameter is subject to the limit deviations speci-fied in table 2.Tmax -Tai.100If one of the limit deviations is to be zero,this shall be statedTmax +Tminin the order,e.g.instead of (550,25)mm,eitherwhere(55*85)mm or (55-8s)mm.Tis the largest wall thickness measured of aTable 1:Limit deviations for the diametertube cross section:of heat treated tubesthe smallest wall thickness measured of atube cross section.Wall thickness,Limit devlations forTubes are generally ordered in terms of outside diameterdiameter,Dand inside diameter.0.05.D and aboveAs specified in table 2.Where the wall thickness is of significance,the tubes mayalso be ordered in torms of outside diameter and wall thick-Above0,05·D1.5 times the valuesness or inside diameter and wall thickness.In this case,theupto0,025·Din table 2.limit deviations specified here refer only to two of threepossible parameters,the deviations for the third being sub-Above 0,025DTwice the values in table 2.ject to agreement.Such tubes shall be ordered in qualitygrade C.Continued on pages 2 to 6.geuth verlag GmoH,Berlin,has the exclusive nght of sale for German Standards (DIN-Normen).04.95DIN 2391 Part 1 Engl.Price group 6Sales No.0106Copyright by the DIN Deutsches Institut Fur Normung E V