ISO INTERNATIONAL STANDARD. Fluid power systems O-rings Part 3: Quality acceptance criteria

INTERNATIONAL STANDARD ISO 3601-3 Second edition 2005-11-01 Fluid power systems O-rings Prt 3: Qulity cceptnce criteri Trnsmissions hydruliques et pneumtiques Joints toriques Prtie 3: Critères de qulité Reference number ISO 3601-3:2005(E) ISO 2005

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Contents Pge Foreword... iv Introduction... v 1 Scope... 1 2 Normtive references... 1 3 Terms, definitions nd symbols... 1 4 Grdes... 3 4.1 Grde N (generl purpose)... 3 4.2 Grde S (specil)... 3 4.3 Grde CS (criticl service)... 3 4.4 Selection of grde... 3 5 Surfce condition... 3 6 Identifiction sttement (reference to this prt of ISO 3601)... 4 ISO 2005 All rights reserved iii

Foreword ISO (the Interntionl Orgniztion for Stndrdiztion) is worldwide federtion of ntionl stndrds bodies (ISO member bodies). The work of prepring Interntionl Stndrds is normlly crried out through ISO technicl committees. Ech member body interested in subject for which technicl committee hs been estblished hs the right to be represented on tht committee. Interntionl orgniztions, governmentl nd non-governmentl, in liison with ISO, lso tke prt in the work. ISO collbortes closely with the Interntionl Electrotechnicl Commission (IEC) on ll mtters of electrotechnicl stndrdiztion. Interntionl Stndrds re drfted in ccordnce with the rules given in the ISO/IEC Directives, Prt 2. The min tsk of technicl committees is to prepre Interntionl Stndrds. Drft Interntionl Stndrds dopted by the technicl committees re circulted to the member bodies for voting. Publiction s n Interntionl Stndrd requires pprovl by t lest 75 % of the member bodies csting vote. Attention is drwn to the possibility tht some of the elements of this document my be the subject of ptent rights. ISO shll not be held responsible for identifying ny or ll such ptent rights. ISO 3601-3 ws prepred jointly by Technicl Committee ISO/TC 20, Aircrft nd spce vehicles, Subcommittee SC 10, Aerospce fluid systems nd components, nd by Technicl Committee ISO/TC 131, Fluid power systems, Subcommittee SC 7, Seling devices. This second edition cncels nd replces the first edition (ISO 3601-3:1987), which hs been techniclly revised. ISO 3601 consists of the following prts, under the generl title Fluid power systems O-rings: Prt 1: Inside dimeters, cross-sections, tolernces nd size identifiction code Prt 3: Qulity cceptnce criteri Prt 5: Suitbility of elstomeric mterils for industril pplictions The following prts re in preprtion: Prt 2: Housing dimensions for generl pplictions Prt 4: Anti-extrusion devices (bck-up rings) iv ISO 2005 All rights reserved

Introduction In fluid power systems, power is trnsmitted nd controlled through fluid (liquid or gs) under pressure within n enclosed circuit. Components must be designed to meet these requirements under vrying conditions. Testing of components to meet performnce requirement provides users bsis of ssurnce for determining design ppliction nd for checking component complince with their stted requirements. ISO 2005 All rights reserved v

INTERNATIONAL STANDARD ISO 3601-3:2005(E) Fluid power systems O-rings Prt 3: Qulity cceptnce criteri 1 Scope This prt of ISO 3601 lys down the qulity cceptnce criteri of O-rings used in fluid systems, the dimensions of which re stndrdized in ISO 3601-1, ISO 16031-1 nd ISO 16031-2. This prt of ISO 3601 lso defines nd clssifies surfce imperfections on O-rings nd specifies mximum cceptble limits for these imperfections. This prt of ISO 3601 is lso pplicble to O-rings to be used in erospce construction. 2 Normtive references The following referenced documents re indispensble for the ppliction of this document. For dted references, only the edition cited pplies. For undted references, the ltest edition of the referenced document (including ny mendments) pplies. ISO 3601-1, Fluid power systems O-rings Prt 1: Inside dimeters, cross-sections, tolernces nd size identifiction code ISO 5598, Fluid power systems nd components Vocbulry ISO 16031-1, Aerospce fluid systems O-rings, inch series: Inside dimeters nd cross sections, tolernces nd size-identifiction codes Prt 1: Close tolernces for hydrulic systems ISO 16031-2, Aerospce fluid systems O-rings, inch series: Inside dimeters nd cross sections, tolernces nd size-identifiction codes Prt 2: Stndrd tolernces for non-hydrulic systems 3 Terms, definitions nd symbols For the purposes of this document, the terms nd definitions given in ISO 5598 nd the following pply. 3.1 bckrind longitudinl imperfection in which the rubber djcent to the flsh line shrinks below the level of the moulding nd hs U -like or W -like cross section with the flsh frequently being rgged or torn [see Figure 1] 3.2 combined flsh combintion of offset, flsh nd prting line projection ISO 2005 All rights reserved 1

3.3 inside dimeter d 1 O-ring inside dimeter 3.4 cross-section dimeter d 2 O-ring cross-section dimeter 3.5 excessive trimming flttened nd often roughened re round the inner nd/or outer dimeters of n O-ring cused by the trimming process [see Figures 2 nd 2b] 3.6 flsh film-like mteril tht extends from the prting line projection or inner nd/or outer dimeters, cused by mould seprtion or present due to indequte trimming [see Figure 3] 3.7 flow mrk thred-like recess, usully curved, of very slight depth in the unflexed stte, with norml surfce texture nd round edge, cused by incomplete flow nd knit of the mteril [see Figure 4] 3.8 foreign mteril ny extrneous mtter embedded in the surfce of the O-ring, e.g. contmintion, dirt, etc. 3.9 indenttion depression, usully irregulr in form, cused by the removl of inclusions from the surfce or the build-up of hrdened deposits on the surfce of the mould cvity [see Figure 5] 3.10 mismtch cross-sectionl rdius in one ring hlf being unequl to tht of the other hlf, cused by dimensionl difference in mould hlves 3.11 non-fill rndomly spced, irregulrly shped surfce indenttion hving corser texture thn the norml O-ring surfce, cused by incomplete filling of, nd or the trpping of ir in, the mould cvity [see Figure 6] 3.12 off-register mislignment of O-ring hlves, cused by the lterl shift of one mould cvity plte reltive to other 2 ISO 2005 All rights reserved

3.13 offset mismtch nd/or off-register of O-ring hlves [see Figure 7] 3.14 prting-line indenttion shllow sucer-like recess sometimes tringulr in shpe, locted on the prting line t the inner nd/or outer dimeters, cused by deformtion of the mould edge t the prting line 3.15 prting-line projection continuous ridge of mteril situted t the prting line of inner nd/or outer dimeters cused by worn or excessively rounded edges of the mould cvity 4 Grdes 4.1 Grde N (generl purpose) Grde N (generl purpose) identifies cceptnce criteri for O-rings intended for generl use. See Tble 1. 4.2 Grde S (specil) Grde S (specil) identifies cceptnce criteri for O-rings intended for pplictions requiring higher level of qulity nd/or precision with respect to dimensionl tolernces of surfce imperfections. For exmple, erospce or criticl industril or utomotive pplictions re covered by this grde. See Tble 2. 4.3 Grde CS (criticl service) This grde identifies cceptnce criteri for O-rings intended for pplictions requiring much higher level of qulity nd/or precision with respect to dimensionl tolernces of surfce imperfections. For exmple, criticl service erospce or medicl pplictions, where the surfce of the O-ring must be ner-perfect to perform in stisfctory mnner, re covered by this grde. See Tble 3. 4.4 Selection of grde If the user does not specify the grde t the time of purchse, Grde N will be ssumed to be the qulity requirement, except for specific erospce pplictions where Grde S will be ssumed to be the qulity requirement. 5 Surfce condition 5.1 The O-ring surfces shll be free from crcks, ruptures, blisters or other imperfections tht re greter thn the limits given in Tbles 1, 2 nd 3 when the unstretched ring is viewed under 2 mgnifier viewer with dequte illumintion. Other methods should be greed between the mnufcturer nd the user. 5.2 There shll be no foreign mteril embedded in the surfce visible under the viewing conditions given in 5.1. ISO 2005 All rights reserved 3

5.3 Flow mrks, non-fills nd indenttions within the limits of Tbles 1, 2 nd 3 shll not be llowed if ) there re more thn three in ny 25 mm length of circumference for Grdes N nd S or there is more thn one in ny 25 mm length of circumference for Grde CS; b) they interconnect; c) there re more thn three tht re seprted from ech other by distnce tht is less thn the mximum limiting dimensions of such imperfection for Grdes N nd S, or there re more thn two tht re seprted from ech other by distnce tht is less thn the mximum limiting dimensions of such imperfection nd only one per 25 mm length of circumference for Grde CS. 5.4 There shll be no flow mrks tht re essentilly rdilly orientted. 5.5 The surfce resulting from ny excessive trimming shll be smoothly blended. 5.6 Wire guges of the pproprite size my be used to determine the size of the defect by comprison. 5.7 In cse of dispute, the methods of mesurement shll be greed upon between the mnufcturer nd the customer. 6 Identifiction sttement (reference to this prt of ISO 3601) Use the following sttement in test reports, ctlogues nd sles literture when electing to comply with this prt of ISO 3601: Surfce imperfection limits re in ccordnce with ISO 3601-3:2005, Fluid power systems O-rings Prt 3: Qulity cceptnce criteri. 4 ISO 2005 All rights reserved

Tble 1 Limits of size for surfce imperfections for Grde N O-rings Dimensions in millimetres Mximum limits of imperfections Surfce imperfection type Digrmmtic representtion Limiting dimensions > 0,8 b u 2,25 Grde N O-rings Cross-section, d 2 > 2,25 u 3,15 > 3,15 u 4,50 > 4,50 u 6,30 > 6,30 u 8,40 b Off-register, mismtch (offset) e 0,08 0,10 0,13 0,15 0,15 Combined flsh (combintion of offset, flsh nd prting line projection) x 0,10 0,12 0,14 0,16 0,18 y 0,10 0,12 0,14 0,16 0,18 When the flsh cn be differentited, it shll not exceed 0,07 mm. g 0,18 0,27 0,36 0,53 0,70 Bckrind u 0,08 0,08 0,10 0,10 0,13 Excessive trimming (rdil tool mrks not llowed) n Trimming is llowed provided the dimension n is not reduced below the minimum dimeter d 2 for the O-ring. Flow mrks (rdil orienttion of flow mrks is not permissible) v 1,50 1,50 6,50 6,50 6,50 k 0,08 0,08 0,08 0,08 0,08 Non-fills nd indenttions (including prting line indenttions) b c Or times the O-ring s inside dimeter (d 1 ), whichever is greter. w 0,60 0,80 1,00 1,30 1,70 t 0,08 0,08 0,10 0,10 0,13 Limits of imperfections for cross sections < 0,8 mm or > 8,40 mm shll be greed upon between mnufcturer nd customer. Round edges. ISO 2005 All rights reserved 5

Surfce imperfection type Tble 2 Limits of size for surfce imperfections for Grde S O-rings Digrmmtic representtion Limiting dimensions > 0,8 b u 2,25 Dimensions in millimetres Mximum limits of imperfections Grde N O-rings Cross-section d 2 > 2,25 u 3,15 > 3,15 u 4,50 > 4,50 u 6,30 >6,30 u 8,40 b Off-register, mismtch (offset) e 0,08 0,08 0,10 0,12 0,13 Combined flsh (combintion of offset, flsh nd prting line projection) x 0,10 0,10 0,13 0,15 0,15 y 0,10 0,10 0,13 0,15 0,15 When the flsh cn be differentited, it shll not exceed mm. g 0,10 0,15 0,20 0,20 0,30 Bckrind u 0,08 0,10 0,10 0,13 Excessive trimming (rdil tool mrks not llowed) n Trimming is llowed provided the dimension n is not reduced below the minimum dimeter d 2 for the O-ring. Flow mrks (rdil orienttion of flow mrks is not permissible) v k 1,50 1,50 5,00 5,00 5,00 Non-fills nd indenttions (including prting line indenttions) w t 0,15 0,08 0,25 0,08 0,40 0,10 0,63 0,10 1,00 0,13 b c Or times the O-ring s inside dimeter (d 1 ), whichever is greter. Limits of imperfections for cross sections < 0,8 mm or > 8,40 mm shll be greed upon between mnufcturer nd customer. Round edges. 6 ISO 2005 All rights reserved

Tble 3 Limits of size for surfce imperfections for Grde CS O-rings Dimensions in millimetres Mximum limits of imperfections Surfce imperfection type Digrmmtic representtion Limiting dimensions > 0,8 b u 2,25 > 2,25 u 3,15 Grde N O-rings Cross-section d 2 > 3,15 u 4,50 > 4,50 u 6,30 >6,30 u 8,40 b Off-register, mismtch (offset) e 0,04 0,04 0,06 0,06 0,08 x 0,07 0,07 0,10 0,13 0,13 Combintion of offset nd prting line projection y 0,10 0,10 0,13 0,13 0,13 Not permissible g Not permissible Bckrind Excessive trimming (rdil tool mrks not llowed) u n Not permissible Trimming is llowed provided the dimension n is not reduced below the minimum dimeter d 2 for the O-ring. Flow mrks (rdil orienttion of flow mrks is not permissible) v k 1,50 1,50 1,50 4,56 4,56 ISO 2005 All rights reserved 7

Tble 3 (continued) Dimensions in millimetres Mximum limits of imperfections Surfce imperfection type Digrmmtic representtion Limiting dimensions > 0,8 b u 2,25 > 2,25 u 3,15 Grde N O-rings Cross-section d 2 > 3,15 u 4,50 > 4,50 u 6,30 >6,30 u 8,40 b 0,08 0,13 d 0,13 0,25 d 0,18 0,38 d 0,25 0,51 d 0,38 0,76 d Non-fills nd w indenttions (including prting line indenttions) t 0,08 0,08 0,10 0,10 0,13 b c d Or 0,03 times the O-ring s inside dimeter (d 1 ), whichever is greter, subject to mximum of 30 mm. Limits of imperfections for cross sections < 0,8 mm or > 8,40 mm shll be greed upon between mnufcturer nd customer. Round edges. Mould deposit indenttions only. Uncceptble for CS O-rings; cceptble within dimensionl limits for N nd S O-rings. Figure 1 Bckrind 8 ISO 2005 All rights reserved

b Rdil orienttion of flow mrk is uncceptble. Acceptble within dimensionl limits. Figure 4 Flow mrks Acceptble within dimensionl limits. Acceptble within dimensionl limits. Figure 5 Mould deposit indenttion Figure 6 Non-fills, inclusions nd indenttions 10 ISO 2005 All rights reserved