© ISO 2015 Steel for the reinforcement of concrete — Part 2 Ribbed bars Aciers pour l’armature du béton — Partie 2 Barres à verrous INTERNATIONAL STANDARD ISO 6935 2 Third edition 2015 12 15 Reference[.]
INTERNATIONAL STANDARD ISO 693 -2 Third edition 01 5-1 -1 Steel for the reinforcement of concrete — Part : Ribbed bars Aciers pour l’armature du béton — Partie 2: Barres verrous Reference number ISO 693 5-2 : 01 (E) I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n © ISO 01 ISO 693 5-2 :2 015(E) COPYRIGHT PROTECTED DOCUMENT © ISO 2015, Published in Switzerland All rights reserved Unless otherwise speci fied, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission Permission can be requested from either ISO at the address below or ISO’s member body in the country of the requester ISO copyright office Ch de Blandonnet • CP 401 CH-1214 Vernier, Geneva, Switzerland Tel +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org ii I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n © ISO 2015 – All rights reserved ISO 693 5-2 :2 015(E) Contents Page Foreword iv Scope Normative references Symbols Terms and de initions f Dimensions, mass per unit length and permissible deviations Requirements for ribs Chemical composition Mechanical properties 9 8.1 Tensile properties 8.2 Bending properties 8.3 Rebending properties after ageing 1 8.4 Fatigue properties 1 Testing 11 9.1 Tensile test 1 9.2 Conditions of testing 1 9.3 Bend test 1 9.4 Rebend test 9.5 Fatigue test 9.6 Chemical composition 10 Designation 12 11 Marking 13 12 1 Marking on the bar 1 Marking of bundles Evaluation of conformity 13 12.2 12.3 General Evaluation of conformity during production Acceptance testing of a speci fic delivery General Evaluation of characteristic values 4 Test report 12.3.3 Evaluation of speci fied minimum/maximum values Annex A (informative) Four examples of marking systems for ribbed bars 17 Annex B (informative) Options for agreement between the manufacturer and purchaser 2 Bibliography © ISO 01 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n iii ISO 693 5-2 :2 015(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies) The work of preparing International Standards is normally carried out through ISO technical committees Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part In particular the different approval criteria needed for the different types of ISO documents should be noted This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part (see www.iso org/directives) Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights ISO shall not be held responsible for identifying any or all such patent rights Details of any patent rights identi fied during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso org/patents) Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement For an explanation on the meaning of ISO speci fic terms and expressions related to conformity assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers to Trade (TB T) see the following URL: Foreword - Supplementary information The committee responsible for this document is ISO/TC 17, Steel, Subcommittee SC 16, Steels for the reinforcement and prestressing of concrete This third edition cancels and replaces the second edition (ISO 6935-2:2007), which has been technically revised The main changes are in Table 4, Table 5, Table 6, 9.1, (new) , 11 and 12 ISO 6935 consists of the following parts, under the general title Steel for the reinforcement of concrete : — Part 1: Plain bars — Part 2: Ribbed bars — Part 3: Welded fabric iv I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n © ISO 01 – All rights reserved INTERNATIONAL STANDARD ISO 693 5-2 :2 015(E) Steel for the reinforcement of concrete — Part : Ribbed bars Scope This part of ISO 6935 speci fies technical requirements for ribbed bars to be used as reinforcement in co nc re te T h i s p a r t o f I S O i s ap p l i c ab le to s te e l de l i ve re d i n the fo r m o f b a r s , c o i l s a n d de - co i le d p ro duc ts I t i nc lude s b o th we ld ab le a n d no n- we ld ab le s te e l s T he p ro duc tio n p ro c e s s i s at the d i s c re tio n o f the m a nu fac tu re r It is not applicable to ribbed bars produced from finished products, such as plates and railway rails Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application For dated references, only the edition cited applies For undated references, the latest edition of the referenced document (including any amendments) applies I S O 4 , Steel a n d steel p ro du cts — Gen era l tech n ica l delivery requ irem en ts ISO/TR 9769, I S O 14 , ISO Steel a n d iro n — Re vie w o f a va ila b le m eth o ds o f a n a lysis Certification scheme for steel bars and wires for the reinforcement of concrete structures 142 , Steel an d iro n — Sa m p lin g an d p rep a tio n o f sa m p le s f or th e determ in a tio n o f ch em ica l co m p o sitio n I S O -1 , Steel f o r th e rein f o rcem en t a n d p re stre ssin g o f co n crete — T e st m eth o ds — Pa rt : Rein f o rcin g b a rs, wire ro d a n d wire Symbols The symbols used in this part of ISO 6935 are listed in © I S O – Al l ri gh ts re s e rve d I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n Tab le ISO 693 5-2 :2 015(E) Table — Symbols Symbol Unit mm % % mm mm mm Rib height Percentage elongation after fracture Percentage total elongation at maximum force Nominal cross-sectional area Rib spacing Nominal diameter of the bar mm — — — — — MPa a MPa a MPa a — — Degree Degree Ribless perimeter Required characteristic value Relative rib area Indices Mean value of individual values Number of individual values a A A gt S c d i k R Σ f f f k, k’ m n n eH m p0,2 R R R s n x i a α β Description n Upper yield strength Tensile strength 0,2 % proof strength, non-proportional extension Standard deviation for individual values Individual value n Transverse-rib flank inclination Transverse-rib inclination MPa = N/mm Reference 4.10, Clause 8.1, 9.1 8.1, 9.1 Clause 5, 9.1 4.11, Clause Clause 5, Clause 6, 9.1, 9.2, 9.3, Clause 10, 11.2, 4.12, Clause 12.2, 12.3.2.3 4.9, Clause 12.3.2.3.1 12.3.2.3.1 12.3.2.3.1 8.1 8.1 8.1 12.3.2.3.1 12.3.2.3.1 4.14, Clause 4.15, Clause 4 Terms and de initions f For the purposes of this document, the following terms and de finitions apply 4.1 cast analysis chemical analysis representative of the cast determined by the manufacturer in accordance with its own procedures [SOURCE: ISO 16020:2005, 2.4.3, modi fied.] 4.2 conformity assessment scheme conformity assessment system related to speci fic objects of conformity assessment, to which the same speci fied requirements, speci fic rules and procedures apply Note to entry: Conformity assessment schemes may be operated at an international, national or sub-national level Note to entry: Certi fication, i.e third party attestation related to products, processes, systems or persons, is applicable to all objects of conformity assessment except for conformity assessment bodies themselves, to which accreditation is applicable characteristic value value having a prescribed probability of not being attained in a hypothetical unlimited test series Note to entry: equivalent to “fractile”, which is de fined in ISO 3534-1:2006 I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n © ISO 2015 – All rights reserved ISO 693 5-2 :2 015(E) Note to entry: a nominal value is used as the characteristic value in some circumstances [SOURCE: ISO 16020:2005, 2.4.10, modi fied – added Note 2.] 4.4 core p a r t o f the c ro s s - s e c ti o n o f the b a r no t co n ta i n i n g e i the r r i b s o r i nde nt ati o n s [SOURCE: ISO 16020:2005, 2.2.5, modi fied.] 4.5 ductility class classi fication of the ductility properties of reinforcing steels based on the value of the ratio of tensile strength to yield strength, as well as the elongation measured either as A A gt Note to entry: see or as Tab l e 4.6 longitudinal rib u n i fo r m c o nti nuo u s r i b p a l le l to the a x i s o f the b a r [SOURCE: ISO 16020:2005, 2.2.7.1, modi fied.] 4.7 S nominal cross-sectional area c ro s s - s e c tio n a l a re a e qu i va le n t to the a re a o f a c i rc u l a r p l a i n b a r o f the no m i n a l d i a me te r [SOURCE: ISO 16020:2005, 2.2.15, modi fied.] 4.8 product analysis chemical analysis carried out on the product [SOURCE: ISO 16020:2005, 2.4.4] 4.9 relative rib area f R area of the projections of all transverse ribs within a de fined length on a plane perpendicular to the longitudinal axis of the bar, divided by this length and the nominal circumference [SOURCE: ISO 16020:2005, 2.2.11, modi fied.] 4.10 rib height a d i s ta nc e fro m the h i ghe s t p o i nt o n the r i b to the s u r fac e o f the c o re , to b e me a s u re d p e r p e nd i c u l a r to the a x i s o f the b a r Note to entry: see Figu re [SOURCE: ISO 16020:2005, 2.2.12, modi fied.] 4.11 rib spacing c d i s ta nce b e t we e n the centre s o f t wo co n s e c u ti ve tra n s ve rs e r i b s me a s u re d p a l le l to the a x i s o f the b a r Note to entry: see Figu re [SOURCE: ISO 16020:2005, 2.2.10, modi fied.] © I S O – Al l ri gh ts re s e rve d I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n ISO 693 5-2 :2 015(E) 4.12 ribless perimeter Σf sum of the distances along the surface of the core between the end of the transverse ribs of adjacent rows measured as the projection on a plane perpendicular to the axis of the bar i [SOURCE: ISO 16020:2005, 2.2.13, modi fied.] 4.13 transverse rib r i b at a n a n gle , e i the r p e r p e n d ic u l a r o r o b l i que , to the lo n g i tud i n a l a x i s o f the b a r [SOURCE: ISO 16020:2005, 2.2.7.2, modi fied.] 4.14 transverse-rib lank inclination f α angle between the flank of a transverse rib and the core surface of a bar measured perpendicular to the lo n g i tud i n a l a x i s o f the tr a n s ve r s e r ib Note to entry: see F i g u re [SOURCE: ISO 16020:2005, 2.2.9, modi fied.] 4.15 transverse-rib inclination β a n gle b e t we e n the r i b a nd the lo n g i tud i n a l a x i s o f the b a r Note to entry: see F i g u re s , a nd [SOURCE: ISO 16020:2005, 2.2.8, modi fied.] Dimensions, mass per unit length and permissible deviations D i me n s io n s , mass p er u nit le n g th a nd p e r m i s s i b le de v i atio n s a re g i ve n in Tab le By agreement b e t we e n the m a nu fac tu re r a nd p u rch a s e r, r ib b e d b a r s who s e no m i n a l d i a me te r s a re o the r th a n tho s e s ho w n i n Tab le may be used A list of options for agreement between the manufacturer and purchaser i s p ro vi de d i n A n ne x B I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n © I S O – Al l ri gh ts re s e rve d ISO 693 5-2 :2 015(E) Table — Dimensions, mass per unit length and permissible deviations Nominal bar diameter a Nominal cross-sectional area d mm 10 12 14 16 20 25 28 32 40 50 Mass per unit length b S0 mm 28,3 50,3 78,5 113 154 201 314 491 616 804 257 964 Nominal c Permissible deviation kg/m 0,222 0,395 0,617 0,888 1,21 1,58 2,47 3,85 4,84 6,31 9,86 15,42 % ±8 ±8 ±6 ±6 ±5 ±5 ±5 ±4 ±4 ±4 ±4 ±4 d Diameters larger than 50 mm should be agreed between the manufacturer and purchaser The permissible deviation on mass for such bars shall be ± % b S0 = 0,785 × d2 c Mass per unit length = 7,85 × 10 −3 × S0 d Permissible deviation refers to a single bar a The delivery length is subject to agreement between the manufacturer and purchaser NOTE Common delivery lengths of straight bars are m, m, 12 m and 18 m Unless otherwise agreed, the permissible deviation on delivery lengths from rolling mill shall be +100 mm Requirements for ribs Ribbed bars shall have transverse ribs Longitudinal ribs may be present or not There shall be at least two rows of transverse ribs equally distributed around the perimeter of the bar The transverse ribs within each row shall be distributed uniformly over the entire length of the bar, except in the area of marking Ribs shall conform to the requirements in Table © ISO 2015 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n ISO 693 5-2 :2 015(E) Table — Requirements for transverse ribs Nominal bar diameter Ribs of uniform height d Crescent-shaped ribs mm R i b he i gh t, a Al l 0,05 M i n i mu m R i b s p ac i n g , 6≤d c d R a n ge β Transverse-rib flank inclination, α Ribless perimeter, Σ f Tr a n s ve r s e - r i b i n c l i n ati o n , < 10 0,5 > 10 0, d 0,065 d ≤ c ≤ 0,7d d ≤ c ≤ 0,7d 0,5 0, 35° ≤ β ≤ 90° α ≥ 45° All All d d ≤ c ≤ 1,0 d d ≤ c ≤ 0,8 d 35° ≤ β ≤ 75° α ≥ 45° i All 0,25 M a x i mu m dπ Requirements for rib parameters may be speci fied by the relative rib area, or by agreement between the m a nu fac tu re r a nd p u rc h a s e r M e a s u re me n t of rib p a me te r s shal l be p e r fo r me d in acc o rd a nce w i th I S O -1 Dimensions de fining the rib geometry in Tab le a re s ho w n i n F i g u re s to W he n l o n g i tud i n a l r ib s a re p re s e n t, the i r he i ght s h a l l no t e xce e d ,1 d Key l o n gi tu d i n al ri b tran s ve rs e ri b Figure 1 — Ribbed bar — De initions of geometry f Key Ri b ro u n d e d tran s i ti o n Figure 2 — Rib lank inclination, α, and rib height, a — Section A-A from Figure f I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n © I S O – Al l ri gh ts re s e rve d ISO 693 5-2 :2 015(E) Table — Tensile properties Ductility properties Speci ied characteristic value Speci ied charac of upper yield strength Speci ied characteristic teristic a f Ductility class A B C D Steel grade B300A-R B400A-R B400AWR B500A-R B500AWR B600A-R B450AWR 300B-R B400B-R B400BWR B500B-R B500BWR B600B-R B300C-R B400C-R B400CWR B500C-R B500CWR B600C-R B450CWR B300D-R B300DWR B350DWR B400DWR B420DWR B500DWR f ReH MPa c f value of elongation value of % Rm/ReH Minimum Maximum 300 400 — — 500 600 450 300 400 — — 1,25 × ReH(min.) — — 500 600 300 400 — — — — 500 600 450 300 350 400 420 500 — — A Minimum Minimum 1,02 14 1,05 10 16 2,5 1,08 14 16 10 16 1,15 1,25 × ReH(min.) — 1,3 × ReH(min.) A gt Minimum 14 10 - 7,5 17 b 1,25 16 b 13 b By agreement between the manufacturer and purchaser, the type of elongation shall be selected between A and A gt If the type of elongation is not speci fied by agreement, A gt should be used a b In the case of the bars with diameter 32 mm or more in ductility class D, the minimum speci fied characteristic value c MPa = N/mm for A may be decreased by % for each mm increase in diameter However, the maximum diminution from the minimum speci fied characteristic value stated in Table is limited to % By agreement between the manufacturer and purchaser, the values shown in speci fied minimum and/or maximum values Table may be used as If a yield phenomenon is not present, the 0,2 % proof strength (Rp0,2 ) shall be determined 8.2 Bending properties The bend test shall be performed in accordance with 9.3 After testing, the bars shall show neither rupture nor cracks visible to a person of normal or corrected vision 10 I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n © ISO 2015 – All rights reserved ISO 693 5-2 :2 015(E) 8.3 Rebending properties after ageing Regarding 15 steel grades of B400A-R, B 400B-R, B 40 0C-R, B 40 0AWR, B 40 0BWR, B400C WR, B400DWR, B420DWR, B50 0A-R, B500B-R, B500C-R, B500AWR, B500BWR, B500C WR and B500DWR, if required by the purchaser, the rebend test shall be performed in accordance with 9.4 NOTE The rebend test is used to verify the ageing properties of the bent bars After tes ting, the bars shall show neither rupture nor cracks visible to a person of normal or corrected vision 8.4 Fatigue properties If required by the purchaser, the manufacturer shall demonstrate the fatigue properties of the product based on axial-force-controlled fatigue testing in the fluctuating tension range in accordance with The speci fied number(s) of stress cycles, stress range(s) σa and maximum stress(es) σmax shall agreed between the purchaser and manufacturer at the time of enquiry and order be as Testing 9.1 Tensile test The tensile test shall be carried out in accordance with ISO 15630 -1 For the determination of percentage total elongation at maximum force, A gt, equidistant marks shall be made on the free length of the test piece For determination of tensile properties, the nominal cross-sectional area of the bar shall be used 9.2 Conditions of testing The conditions of testing are given in Table Table — Conditions of testing Manufacturing and delivery conditions of the product Conditions of testing (test pieces) Produced in straight lengths by hot rolling Produced in straight lengths by cold working Produced and delivered as coil As delivered a or aged b Aged b Straightened and aged a Aged in the case of dispute b Aged means: Heating of the tes t piece to 10 °C , maintaining at this temperature ± 10 °C for a period of h +15 and then cooling in s till air to room temperature The method of heating is left to the discretion of the manufacturer 9.3 Bend test The bend test shall be carried out in accordance with ISO 15630 -1 The tes t piece shall be bent to an angle between 160 ° and 180 ° over a mandrel of the diameter speci fied in Table © ISO 01 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n 11 ISO 693 5-2 :2 015(E) Table — Mandrel diameter to be used for the bend test Dimensions in millimetres Nominal bar diameter d Mandrel diameter (max.) a, b ≤ 16 16 < d ≤ 32 32 < d ≤ 50 a 3d 6d 7d For nominal diameters larger than mm, the mandrel diameter in bend tes ts shall be agreed between the manufacturer and purchaser b By agreement between the manufacturer and purchaser, larger mandrel diameters may be used 9.4 Rebend test The rebend test shall be carried out in accordance with ISO 15630 -1 The test piece shall be bent over a mandrel of the diameter speci fied in Table The angle of bend before heating (ageing) shall be at least 90 °, and the angle of rebend shall be at least 20 ° Both angles shall be measured before unloading Table — Mandrel diameter to be used for the rebend test Dimensions in millimetres Nominal bar diameter d Mandrel diameter ≤ 16 16 < d ≤ 25 25 < d ≤ 50 a (max.) a, b 5d 8d 10 d For nominal diameters larger than mm, the mandrel diameter in rebend tes ts shall be agreed between the manufacturer and purchaser b By agreement between the manufacturer and purchaser, larger mandrel diameters may be used 9.5 Fatigue test The fatigue test shall be carried out according to ISO 15630 -1 9.6 Chemical composition In general, the chemical composition is determined by spectrometric methods In case of dispute about the analytical method, the chemical composition shall be determined by an appropriate referee method speci fied in one of the International Standards listed in ISO/TR 9769 10 Designation Ribbed bars according to this part of ISO 6935 shall be designated in the following order: a) reinforcing steel; b) a reference to this part of ISO 6935 (i.e ISO 6935-2); c) the nominal diameter, in millimetres, according to Table ; d) the steel grade 12 I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n © ISO 01 – All rights reserved ISO 693 5-2 :2 015(E) E XAMPLE Reinforcing s teel ISO 6935 -2 – B50 C WR 11 Marking 11.1 Marking on the bar All bars should be identi fiable by permanent marks that indicate a) the steel grade, and b) the name of the manufacturer Some examples of multinational marking systems are shown in Annex A 11.2 Marking of bundles Each bundle of bars shall have a label stating the name of the manufacturer, a reference to this part of ISO 6935 (i.e ISO 6935 -2) , the steel grade, the nominal diameter, the cast number or reference related to the test record and country of origin 12 Evaluation of conformity 12 General Certi fication and inspection of reinforcement can be performed a) in accordance with a certi fication following a conformity assessment scheme, see 12 , or b) according to testing of a speci fic delivery, see 12 Evaluation of conformity during production This clause speci fies requirements for the evaluation of conformity during production NOTE ISO 10144 speci fies scheme requirements for the certi fication for the continuous production of steel bars for the reinforcement of concrete in order to verify the conformity with requirements speci fied in product standards such as ISO 6935 -1 and ISO 6935 -2 For each of the characteristics speci fied in this part of ISO 6935 except chemical composition, one test piece shall be taken per 40 t for all diameters, with at least three test pieces per cast and nominal diameter The chemical composition (cast analysis) shall also be determined for all casts The contents of the elements speci fied in this standard shall be determined in this analysis Each individual value > xi , 95 xi shall satisfy the equation fk (2) where fk is the required characteristic value according to Table The mean value of the test unit shall satisfy the equation m > f k + ks (3) where k is the acceptability index according to Table 10 ; and © ISO 01 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n 13 ISO 693 5-2 :2 015(E) s i s the s t a n d a rd de v i ati o n o f the te s t re s u l ts P ro ve n va lue s o f ks fo r e ach p ro duc t a n d m a nu fac tu re r s h a l l b e u s e d The mean value requirement of Formula (3) does not apply if all individual values lie above the required ch a rac te r i s tic va lue All casts shall comply with the requirements for the chemical composition including the carbon e qu i va le nt A l l o the r re qu i re me nt s s h a l l b e me t fo r e ach i nd i v idu a l te s t p ie ce Where test results are unsatisfactory according to this clause, the manufacturer shall immediately take the necessary precautions Casts that not conform to the requirement shall be set aside Table 10 — Acceptability index (k) as a function of the number (n) of the test results n k n k ,40 30 ,08 ,09 40 ,01 ,89 50 ,9 ,75 60 ,9 ,65 70 ,9 10 , 57 80 1,89 11 ,50 90 , 87 12 , 45 10 1,86 13 ,40 150 , 82 14 ,36 200 ,7 15 ,33 250 ,7 16 ,30 300 ,7 17 ,27 40 ,75 18 ,25 500 , 74 19 ,23 10 0 ,71 20 ,21 ∞ 1,64 12.3 Acceptance testing of a speci ic delivery f 12 General P ro vi s io n s re ga rd i n g the n atu re , e x tent a nd e va lu atio n o f accep ta nce te s ti n g o n del i ver ie s o f rei n fo rc i n g steel not subject to certi fication following a conformity assessment scheme are given in Acceptance testing of a speci fic delivery shall be performed according to By agreement between the manufacturer and purchaser, 12 3.3 a nd 12 3.2 may be used 12 Evaluation of characteristic values 12 Organization T he te s ts shall be o r ga n i z e d a nd c a r r ie d o ut acc o rd i n g to an a g re e me n t b e t we e n manufacturer, taking into consideration the national rules of the receiving country 14 I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n the p u rch a s e r a nd © I S O – Al l ri gh ts re s e rve d ISO 693 5-2 :2 015(E) 12 2 Extent of sampling and testing For the purpose of testing, the delivery shall be subdivided into test units with a maximum mass of 50 t, or a fraction thereof Each test unit shall consist of products of the same steel grade and the same nominal diameter from the same cast The manufacturer shall firm in the test report that all samples in the test unit originate from the same cast The chemical composition (cast analysis) shall be stated in this test report Test pieces shall be taken from each test unit as follows: a) two test pieces from various bars for testing the chemical composition (product analysis); b) a minimum of 15 test pieces (if appropriate, 60 test pieces, see 12.3.2.3.1) from various bars for testing all other properties speci fied in this part of ISO 6935 12 3 Evaluation of the results 12 3 Inspection by variables For properties that are speci fied as characteristic values, the following shall be determined: a) all individual values, xi, of the 15 test pieces (n = 15); b) the mean value, m15 (for n = 15); c) the standard deviation, s15 (for n = 15) The test unit corresponds to the requirements, if the condition stated below is ful filled for all properties: (4) m 15 − 2,33 × s 15 ≥ fk where is the required characteristic value; fk 2,33 , for n = 15 for a failure rate of % ( p = 0,95) at a is the value for the acceptability index, k probability of 90 % (1 – α ∑ ( xi − m ) s15 = = 0,90) (5) 15 14 If the condition stated above is not ful filled, the index k′ = m 15 − (6) fk s 15 is determined from the test results available Where k′ ≥ 2, testing can be continued In this case, 45 additional test pieces shall be taken and tested from different bars in the test unit, so that a total of 60 test results are available (n = 60) The test unit shall be considered to comply with the requirements, if the condition stated below is ful filled for all properties: (7) m 60 − 1, 93 × s 60 > fk , for n = 60 for a failure rate of % ( p = 0,95) at a where 1,93 is the value for the acceptability index, k probability of 90 % (1 – α = 0,90) © ISO 2015 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n 15 ISO 693 5-2 :2 015(E) 12 3 Inspection by attributes When testing properties are speci fied as maximum or minimum values, all results determined on the 15 test pieces shall comply with the requirements of this part of ISO 6935 In this case, the test unit shall be considered to comply with the requirements The tests may be continued when at most results not conforming to the conditions occur In this case, 45 additional tes t pieces from various bars in the tes t unit shall be tes ted, so that a total of 60 tes t res ults are available T he tes t unit complies with the requirements if not more than of the 60 res ults not conform to the conditions 12 3 Chemical composition Both test pieces shall comply with the requirements in this part of ISO 6935 12.3.3 Evaluation of speci ied minimum/maximum values f Tes ts shall be carried out according to the following: a) Bars of the same cast shall constitute one group For every 50 t or fraction thereof, one tensile test and one bend/rebend test shall be carried out for each bar diameter; b) c) E ach individual tes t res ult shall meet the required values in Table 6, and the required bending/rebending properties in and One cast analysis shall be carried out for every cast to verify chemical composition (C lause ) Samples shall be taken in accordance with ISO 14284; If any test result does not meet the requirements, retests may be carried out, according to ISO 404; d) The manufacturer shall submit a test report stating that the products of the delivery satisfy the chemical and mechanical properties de fined in C lauses and , and a firmation that the other requirements of this part of ISO 6935 are ful filled 12 Test report The tes t report shall at leas t contain the following information: a) designation of the reinforcing steel in accordance with this part of ISO 6935; b) marking on the reinforcing steel; c) date of testing; d) mass of the test unit; e) 16 tes t res ults I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n © ISO – All rights reserved