INTERNATIONAL STANDARD ISO 16112 Second edition 2017-02 Compacted (vermicular) graphite cast irons — Classification Fontes graphite vermiculaire (compacté) — Classification Reference number ISO 16112:2017(E) © ISO 2017 ISO 16112:2017(E) COPYRIGHT PROTECTED DOCUMENT © ISO 2017, Published in Switzerland All rights reserved Unless otherwise specified, no part o f 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 o f the requester ISO copyright o ffice 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 © ISO 2017 – All rights reserved ISO 16112:2017(E) Contents Page Foreword iv Introduction v Scope Normative references Designation Order information Manufacture Requirements 7.1 General f f 7.4 Test pieces machined from samples cut from a casting 7.5 Hardness 7.6 Graphite structure Sampling 8.1 General 8.2 Cast samples 10 10 f 10 10 8.2.4 Cast-on samples 10 8.2.5 Test pieces machined from cast samples 11 8.3 Samples cut from a casting 11 8.3.1 General 11 8.3.2 Other conditions 11 8.4 Formation of test units and number of tests 11 8.4.1 Examples of test units 11 8.4.2 Number of tests per test unit 11 Test methods 12 9.1 Tensile test 12 9.2 Hardness test 13 10 Retests 14 10.1 Need for retests 14 14 10.3 Nonconforming test results 14 10.4 Heat treatment of samples and castings 14 Annex A (informative) Additional information on compacted (vermicular) graphite cast irons 15 Annex B (informative) Compacted (vermicular) graphite cast iron nodularity evaluation 18 3 Terms and definitions 7.2 Tes t p ieces machined ro m s ep arately cas t s amp les 7.3 Tes t p ieces machined ro m s ide- by- s ide and cas t- o n s amp les 0.2 8.2 Frequency and numb er o 8.2 S ep arately cas t s amp les 8.2 S ide- by- s ide cas t s amp les tes ts Tes t validity Annex C (informative) Compacted (vermicular) graphite cast irons — Properties and typical applications 22 Annex D (informative) Cross-references of ISO 16112 grade designations to other standard grades of compacted (vermicular) graphite cast iron 23 Bibliography 24 © ISO 2017 – All rights reserved iii ISO 16112:2017(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies) The work o f 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 o f 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 di fferent types o f ISO documents should be noted This document was dra fted 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 o f the elements o f this document may be the subject o f patent rights ISO shall not be held responsible for identi fying any or all such patent rights Details o f any patent rights identified during the development o f 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 in formation given for the convenience o f users and does not constitute an endorsement For an explanation on the meaning o f ISO specific terms and expressions related to formity assessment, as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html This document was prepared by Technical Committee ISO/TC 25, Cast irons and pig irons This second edition cancels and replaces the first edition (ISO 16112:2006), which has been technically revised with the following changes: — Brinell hardness values have been moved from Table and Table to Table A.1; — property values for cast-on samples with relevant wall thickness t ≤ 12,5 mm have been removed from Table because all data entries for t ≤ 12,5 mm were the same as the values for relevant wall thickness 12,5 mm < t ≤ 30 mm; — Annex B has been expanded to provide a more comprehensive explanation of the nodularity evaluation technique; — Annex C has been deleted and replaced because the series production experience gained since the first publication o f ISO 16112 in 2006 has surpassed the scope o f the annex iv © ISO 2017 – All rights reserved ISO 16112:2017(E) Introduction T h i s c u ment de a l s with the cla s s i fic ation o f comp ac te d (verm ic u lar) graph ite c a s t i ron s (C GI ) in accordance with the mechanical properties of the material The properties of compacted (vermicular) graphite cast irons depend on their graphite and matrix microstructure The mechanical properties of the material can be evaluated on machined test pieces prepared from — s ep a rately c a s t s a mple s , — s a mple s c as t i n the mou ld a longs ide the c as ti ng , with a j oi nt ru n n i ng s ys tem, here a fter c a l le d s ide b y- s ide s ample s , or — samples, or s a mp le s c a s t o nto — purchaser) s a mple s c ut from either the c a s ti n g o r the here a fter re fer re d to r u n n i ng s ys tem , as c a s t- o n a c as ti ng (on ly when an agre ement i s made b e twe en the manu fac tu rer and the T he materia l grade i s defi ne d b y me ch an ic a l prop er tie s me a s u re d on mach i ne d te s t pie ce s prep a re d from s ep arately c as t s ample s , c a s t- on s ample s , or s ample s c ut the manufacturer and the purchaser Annex A provide s typica l prop er tie s for comp ac te d from the c as ti ng b y agre ement b e twe en (verm ic u l ar) graph ite c as t i ron s ob ta i ne d in s ep arately c as t te s t b ars Annex B f f microstructure Annex C f f f (vermicular) graphite cast irons Annex D provides cross-references of ISO 16112 grade designations to other national and international standard grades of compacted (vermicular) graphite cast iron provide s provide s i n ormation i n ormation on on a pro ce du re prop er tie s a nd to de term i ne example s or the graph ite typica l no du la rity appl ic ation s o o the comp ac te d Re ference s u s e d i n the prep a ration o f th i s c u ment are l i s te d i n the B ibl io graphy © ISO 2017 – All rights reserved v INTERNATIONAL STANDARD ISO 16112:2017(E) Compacted (vermicular) graphite cast irons — Classification Scope T h i s c ument s p e c i fie s five grade s o f comp ac te d (verm ic u la r) graph ite c as t i ron s This c u ment s p e ci fie s five grade s machined test pieces prepared from — s ep a rately c a s t s a mple s , — s ide -b y- s ide c a s t s a mple s , b as e d on the m i ni mu m me cha nic a l prop er tie s me as u re d on — cast-on samples, or — samples cut from a casting Normative references T he fol lowi ng c u ments are re ferre d to i n the tex t i n s uch a way th at s ome or a l l o f thei r content s titute s re qu i rements o f th i s c u ment For date d re ference s , on ly the e d ition cite d appl ie s For u ndate d re ference s , the late s t e d ition o f the re ference d c ument (i nclud i ng a ny amend ments) appl ie s ISO 945-1, Microstructure of cast irons — Part 1: Graphite classification by visual analysis ISO 6506-1, Metallic materials — Brinell hardness test — Part 1: Test method ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature ISO/TR 15931, Designation system for cast irons and pig irons 3 Terms and definitions For the pu r p o s e s o f th i s c u ment, the fol lowi ng term s and defi n ition s apply ISO and IEC maintain terminological databases for use in standardization at the following addresses: — IEC Electropedia: available at http://www.electropedia org/ — ISO Online browsing platform: available at http://www.iso org/obp 3.1 compacted (vermicular) graphite cast iron c as t materi a l, i ron a nd c arb on b as e d, the c arb on b ei ng pre s ent ma i n ly i n the form o f comp ac te d (vermicular) graphite particles that appear vermicular on a two-dimensional plane of polish, the graphite particles being embedded in a matrix consisting of ferrite, ferrite/pearlite, or pearlite N o te to entr y: Re ference m ic ro grap h s a re p ro vide d i n Annex B 3.2 graphite modification treatment process that brings the liquid iron into contact with a substance to produce graphite in the pre dom i na ntly comp ac te d (verm ic u la r) © ISO 2017 – All rights reserved form du ri ng s ol id i fic ation ISO 16112:2017(E) 3.3 separately cast sample sample cast in a separate sand mould under representative manufacturing conditions and material grade 3.4 side-by-side cast sample sample cast in the mould alongside the casting, with a connected but separate running system 3.5 cast-on sample sample attached directly to the running system or the casting 3.6 sample cut from the casting sample obtained directly from the casting 3.7 relevant wall thickness section of the casting, agreed between the manufacturer and the purchaser, to which the determined mechanical properties shall apply Note to entry: The cooling rate o f the relevant wall thickness can be used to determine the size o f separately cast or cast-on samples to ensure representative microstructures and properties Designation The material is designated according to ISO/TR 15931 The relevant designations are given in Tables and In the case o f test pieces prepared from separately cast samples, the letter “S” is added at the end o f the grade designation In the case o f test pieces prepared from side-by-side or cast-on samples, the letter “U” is added at the end o f the grade designation Order information The following in formation shall be supplied by the purchaser: a) the complete designation of the material; b) any special requirements which shall be agreed upon between the manu facturer and the purchaser All agreements between the manu facturer and the purchaser shall be made by the time o f acceptance of the order Manufacture The method of producing compacted (vermicular) graphite cast iron and its chemical composition shall be left to the discretion of the manufacturer, who shall ensure that the requirements of this document are met for the material grade specified in the order NOTE When compacted (vermicular) graphite cast iron is to be used for special applications, the chemical composition and heat treatment can be agreed upon between the manufacturer and the purchaser © ISO 2017 – All rights reserved ISO 16112:2017(E) Requirements 7.1 General T he m i n i mu m ten s i le prop er tie s o f comp ac te d (verm ic u l ar) graph ite c as t i ron s s l l b e a s s p e ci fie d i n Tables and P ro duc tion te s t re s u lts sh a l l me e t the m i n i mum ten s i le prop er ty re qui rements s p e c i fie d i n Table Table or Stati s tic a l ana lys i s me tho d s s l l b e u s e d to e s tab l i s h pro ce s s c ap abi l ity to me e t the ten s i le prop er ty re qu i rements 7.2 Test pieces machined from separately cast samples The minimum measured mechanical properties of compacted (vermicular) graphite cast irons, f Figure 1, Figure or Figure Table The material designation is based on the minimum mechanical properties obtained in cast samples with a thickness of 25 mm This designation is irrespective of the de term i ne d u s i ng te s t pie ce s mach i ne d rom s ep a rately c as t s ample s accord i ng to sh a l l b e as s p e ci fie d i n typ e o f c a s t s ample Table — Mechanical properties measured on test pieces machined from separately cast samples Tensile strength 0,2 % proof strength Rm Rp0,2 Material designation ISO 16112/JV/300/S ISO 16112/JV/350/S ISO 16112/JV/400/S ISO 16112/JV/450/S ISO 16112/JV/500/S NO TE T he va lue s fo r MPa 300 350 400 450 500 MPa 210 245 280 315 350 Elongation A % 2,0 1,5 1,0 1,0 0,5 the s e m ate r i a l s ap p l y to c a s ti n gs c a s t i n s a nd mo u ld s o f co mp a rab le the r m a l b e h avio u r S ub j e c t to a me nd ments ag re e d up o n i n the o rde r, the y c a n ap p l y to c a s ti n gs o b ta i ne d b y a l te r n ati ve me tho d s NOTE Whatever the method used for obtaining the castings, the grades are based on the f mould or a mould of comparable thermal behaviour NOTE Tensile testing requires sound test pieces in order to ensure pure uniaxial stress during the test me ch a n ic a l p ro p e r tie s me a s u re d o n te s t p ie ce s m ach i ne d © ISO 2017 – All rights reserved ro m s a mp le s s ep a rate l y c a s t i n a s a nd ISO 16112:2017(E) Dimensions in millimetres a) Types I, IIa and III b) Type IIb Type Dimension u v x ya a b zb I 12,5 40 30 80 IIa IIb III 25 25 50 55 90 90 40 40 to 50 60 100 100 150 A function of the test-piece length Fo r i n fo r m atio n o n l y z shall be chosen to allow a test piece of the dimensions shown in Figure to be machined from the sample Figure — Separately cast or side-by-side cast samples (option 1) The thickness of the sand mould surrounding the samples shall be — m m m i n i mum for typ e s I , I I a a nd I I b , or — m m m i n i mu m for typ e I I I NOTE For the manufacture of thin-walled castings or castings in metal moulds, the tensile properties can, f f thickness, u, less than 12,5 mm b y agre ement b e twe en the m a nu fac tu rer a nd the p u rch a s er, b e de ter m i ne d on te s t p ie ce s ta ken rom s a mp le s o © ISO 2017 – All rights reserved ISO 16112:2017(E) Test methods 9.1 Tensile test The tensile test shall be carried out in accordance with ISO 6892-1 The preferred test-piece diameter is 14 mm but, for technical reasons and for test pieces machined from samples cut from the casting, it is permitted to use a test piece of a different diameter (see Figure 5) In either case, the original gauge length of the test piece shall conform to Formula (1): L o = 5,65 × √So or L o = × d (1) where Lo So d is the original gauge length; is the original cross-sectional area of the test piece; is the diameter of the test piece along the gauge length If the above formula for Lo is not applicable, then an agreement shall be made between the manufacturer and the purchaser on the dimensions of the test piece A test piece with a di fferent gauge length may be agreed between the manu facturer and purchaser 12 © ISO 2017 – All rights reserved ISO 16112:2017(E) Dimensions in millimetres a b d Lo 10 14b 20 25 35 50 70 100 In principle Preferred dimension Lca 30 42 60 84 120 where is the original gauge length; i.e Lo = × d; is the diameter of the test piece along the gauge length; L c is the parallel length; L c > L o (in principle, L c − L o > d); lt is the grip length of the test piece; L t is the total length of the test piece, which depends on L c and lt; r is the transition radius, which shall be at least mm; Rz is the maximum surface roughness, expressed in µm NOTE The method of gripping the ends of the test piece can be agreed between the manufacturer and the purchaser Lo d Figure — Tensile test piece 9.2 Hardness test If agreed between the manufacturer and the purchaser, the hardness shall be determined as Brinell hardness in accordance with ISO 6506-1 Alternative hardness tests may also be agreed upon The test shall be carried out on the test pieces, or at one or several points on the casting, after preparation of the testing area in accordance with the agreement between the manufacturer and the purchaser I f the measuring points are not the subject o f an agreement, they shall be chosen by the manu facturer I f it is not possible to carry out the hardness test on the casting, then by agreement between the manu facturer and the purchaser, the hardness test may be carried out on a knob cast-on to the casting © ISO 2017 – All rights reserved 13 ISO 16112:2017(E) 10 Retests 10.1 Need for retests Retests shall be carried out if a test is not valid (see 10.2) Re te s ts are p erm itte d re qu i rements for to be ca rrie d out the s p e ci fie d grade (s e e if a 10.3) te s t re s u lt e s no t me e t the me cha n ic a l prop er ty 10.2 Test validity A test is not valid if there is: a) a fau lty mou nti ng o f the te s t pie ce or de fe c tive op eration o f the te s t mach i ne; b) a defective test piece because of incorrect pouring or incorrect machining; c) a fracture of the test piece outside the gauge length; d) a casting defect in the test piece, evident after fracture In the above cases, a new test piece shall be taken from the same sample or from a duplicate sample cast at the same time The result of the retest shall be substituted for the result of the invalid test 10.3 Nonconforming test results I f any te s t gi ve s re s u lts wh ich no t form to the s p e c i fie d re qu i rements , for re as on s o ther th an those given in 10.2, the manufacturer shall have the option to conduct retests If the manufacturer conducts retests, two retests shall be carried out for each failed test I f the re s u lts o f b o th re te s ts me e t the s p e c i fie d re qu i rements , the materia l sh a l l b e de eme d to form to this document I f the re s u lts o f one or b o th re te s ts not to conform to this document fa i l to me e t the s p e ci fie d re qu i rements , the materi a l sha l l b e de eme d 10.4 Heat treatment of samples and castings Un le s s o ther wi s e s p e c i fie d, i n the c a s e o f ca s ti ngs i n the as - c as t cond ition with me chan ic a l prop er tie s no t i n formance with th i s c u ment, a he at tre atment may b e c a rrie d out In the case of castings which have undergone a heat treatment and for which the test results are not f f samples In this event, the samples shall receive the same number of heat treatments as the castings If the results of the tests carried out on the test pieces machined from the re-heat-treated samples f f requirements or to this document s ati s ac tor y, the ma nu ac turer sh a l l b e p erm itte d to re -he at-tre at the c as ti ngs a nd the repre s entati ve are s ati s ac tor y, then the re -he at-tre ate d c a s ti ngs s l l b e regarde d as orm i ng to the s p e ci fie d T he nu mb er o f re -he at-tre atment c ycle s sh a l l no t exce e d two 14 © ISO 2017 – All rights reserved ISO 16112:2017(E) Annex A (informative) Additional information on compacted (vermicular) graphite cast irons Additional in formation on mechanical and physical properties o f compacted (vermicular) graphite cast irons is given in Table A.1 © ISO 2017 – All rights reserved 15 Material designation ISO 16112/JV/400 ISO 16112/JV/450 Property Units Temperature Ultimate tensile strength, Rma MPa 0,2 % proof stress, MPa 23 °C 100 °C 400 °C 23 °C 100 °C 400 °C 23 °C 100 °C 400 °C 23 °C 100 °C 400 °C 23 °C 300 to 375 275 to 350 225 to 300 210 to 260 190 to 240 170 to 220 2,0 to 5,0 1,5 to 4,5 1,0 to 4,0 130 to 145 125 to 140 120 to 135 140 to 210 350 to 425 325 to 400 275 to 350 245 to 295 220 to 270 195 to 245 1,5 to 4,0 1,5 to 3,5 1,0 to 3,0 135 to 150 130 to 145 125 to 140 160 to 220 400 to 475 375 to 450 300 to 375 280 to 330 255 to 305 230 to 280 1,0 to 3,5 1,0 to 3,0 1,0 to 2,5 140 to 150 135 to 145 130 to 140 180 to 240 450 to 525 425 to 500 350 to 425 315 to 365 290 to 340 265 to 315 1,0 to 2,5 1,0 to 2,0 0,5 to 1,5 145 to 155 140 to 150 135 to 145 200 to 250 500 to 575 475 to 550 400 to 475 350 to 400 325 to 375 300 to 350 0,5 to 2,0 0,5 to 1,5 0,5 to 1,5 145 to 160 140 to 155 135 to 150 220 to 260 23 °C 23 °C 23 °C 0,50 to 0,55 0,30 to 0,40 0,65 to 0,75 0,26 7,0 47 45 42 11 0,47 to 0,52 0,27 to 0,37 0,62 to 0,72 0,26 7,0 43 42 40 11 0,45 to 0,50 0,25 to 0,35 0,60 to 0,70 0,26 7,0 to 7,1 39 39 38 11 0,45 to 0,50 0,25 to 0,35 0,60 to 0,70 0,26 7,0 to 7,2 38 37 36 11 0,43 to 0,48 0,20 to 0,30 0,55 to 0,65 0,26 7,0 to 7,2 36 35 34 11 Rp0,2 a Elongation, A a % Elastic modulus a, b GPa Brinell hardness Endurance ratio: rotating-bending tension-compression 3-point bending Poisson’s ratio © ISO 2017 – All rights reserved D en s ity T herma l conduc tivity Thermal expansion co e ffic ient a b g/cm W/(m·K) μm/(m· K ) Wall thickness 25 mm Secant modulus (200 MPa to 300 MPa) 23 °C 100 °C 400 °C 100 °C ISO 16112/JV/300 ISO 16112/JV/350 ISO 16112/JV/500 ISO 16112:2017(E) 16 Table A.1 — Information on mechanical and physical properties of compacted (vermicular) graphite cast irons © ISO 2017 – All rights reserved Table A.1 (continued) Property Sp e c i fic he at c ap ac ity Matrix structure a b Units Temperature J/(g·K) 400 °C 100 °C Wall thickness 25 mm Secant modulus (200 MPa to 300 MPa) ISO 16112/JV/300 ISO 16112/JV/350 12,5 0,475 pre m i n a ntl y ferritic 12,5 0,475 ferritic-pearlitic Material designation ISO 16112/JV/400 ISO 16112/JV/450 12,5 0,475 pearlitic-ferritic 12,5 0,475 pre m i n a ntl y pearlitic ISO 16112/JV/500 12,5 0,475 fu l l y p e a rl itic ISO 16112:2017(E) 17 ISO 16112:2017(E) Annex B (informative) Compacted (vermicular) graphite cast iron nodularity evaluation The graphite nodularity o f compacted (vermicular) graphite cast iron is expressed as the areapercentage o f graphite particles that are predominantly spheroidal or nodular in shape (similar to B.1 form VI, form V and form IV according to ISO 945-1) B.2 The level o f nodularity depends not only on how the cast iron is prepared (nature o f the basic cast iron, residual magnesium content, inoculation level, etc.), but also on the cooling rate of the section in question Moreover, some degeneration o f the graphite in contact with the mould is usually observed, resulting in a certain extent o f flake (lamellar) graphite at the surface rim zone o f the casting B.3 The nodularity percentage is generally determined at ×100 magnification on a polished cut section o f the specimen Accurate analysis requires that the polished surface o f the specimen is o f su fficient quality to assess the true size and shape o f the graphite particles The nodularity can be measured by chart comparison techniques, semiautomatic image analysis or automatic image analysis To ensure accurate measurement by image analysis, the lighting should have uni form intensity The grey-scale threshold value should be set such that all graphite particles (foreground) are clearly defined A minimum field-o f-view area o f mm2 is recommended Pixel size in the image to be analysed should B.4 be less than µm Depending on the image resolution, graphite coarseness and carbon equivalent, more than one measurement field might be required The roundness shape factor is recommended as the basis for nodularity measurement by image analysis Roundness is defined in the following Formula (B.1) and accompanying illustration, Figure B.1: B.5 Roundness = A 4× A = Am π × l m (B.1) Key area of circle of diameter m area of the graphite particle in question m maximum axis length of the graphite particle in question = maximum distance between two points on the graphite particle perimeter A m l A l Figure B — Roundness definition 18 © ISO 2017 – All rights reserved ISO 16112:2017(E) B.6 Grap hite p articles greater than o r equal to m μm ( l ≥ μm) are clas s ified by the ro undnes s shape factor as either nodular, intermediate or compacted (vermicular) graphite as shown in Table B.1 Particles with a maximum axis length less than 10 µm and particles touching the image boundaries are no t included in the analys is Flake grap hite and o ther undermo dified s tructures are als o no t co ns idered in the analys is b ecaus e flake grap hite is no t p ermitted in the co mp acted (vermicular) structure, except in the surface rim zone (see 7.5 and should not be conducted grap hite iro n ) I f flake grap hite is vis ually o b s erved, the cas tings rep res ented by that s amp le s ho uld b e rej ected I n s uch cas es , the calculatio n o f no dularity is no t relevant Table B — Graphite particle classification by roundness shape Roundness shape factor factor Graphite form >0,625 to 0,525 to 0,625