(Reattirmed 2008 ) Indian Standard METHOD FOR BEND TEST (Second Revision ) ‘Third Reprint FEBRUARY 1997 UDC 669 : 620,163.24 © Copyright 1986 BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002 Gr3 January 19861S: 1599 - 1985 (Sapereuding 100-1074 8 sn nes Indian Standard METHOD FOR BEND TEST ( Second Revision ) Methods of Physi Chairman Smat P. K, Graxnavanry Members Sux R. K, Aznor Smut. owox (dura) Suar Sout Konan Base 1 Tests Sectional Committee, SMDC 8 Aoprsmsing ‘The Tuta Tron & Stee! Co Ltd, Jamshedpur Steel Tubes Led, Ganaur ( Haryana ) M,N. Dastur & Co (P) Led, Caleutta ‘Sunt S. Sex Gorra ( Alternate) Suarke K-Buarta Sumt RN. Brawas ‘Quality Marking Centre, Auaritsar Steel‘Authority of India Lid ( Durgapur Steel Plant), Durgapur ‘Sums T. 8. Tewans ( Allraae) Da A. Cuaxnanonsy ‘Usha Martin Industries Led, Caleutia ‘Sunt H. Mascavrany ( Allenate) Swark. K, Cuzsian Tadian Aluminium Co Lid, Caleutta ‘Sir Pawgas Dr ( Allemate) Dn R.F. Dasenas Indian Telephone Industries Ltd, Bangalore Saat V-V. Puan ( Ara Sunt P, Raoxoruanta Ro ( ‘National Phical Laboratory (OSIR ), New Dali Directorate ‘of ‘Technical Development “hod Production (Ait), New Del Alernate) ‘Blue Siar Limited, Bombay ) [National Test House, Caleutta ‘Smat DS. Masoupan ( Allrnate) Sunr.A. Hague ‘The Tata Tron and Stee! Co Ltd, Jamshedpur ‘Sunt ALS. Wasa ( Alternate) SuarN. C. Hose ‘Sinz$.R. Dr ( Alienate) Suni. V. Kenan ‘Suarj. V. Roux ann: ( Allemete) Suni. Rowan, "in whol Publier shall be deemed to be ha kfingement of copyright under the mid “Act Ministry of Railways Fuel Instruments & Engineers Pvt Ltd, Ichalkaranit “Mining & Allied Machinery Corporation Ltd, Durgapur ( Coatiusd on page2) © Copyright 196 BUREAU OF INDIAN STANDARDS Th ei rar ne tn Care 0 ad ‘n pa Fr by any means except with written permission of the1B + 1599 - 1985 ( Continued from page 1) Members Represmting SanrK.S, Laramnamarat Avery Tndia Led, Caloutes we'btionwar Indian Tube Co Led, Jamshedpur sme beievawee oy tadian ; ‘Sunt R, Raves Rao ( Altemate) ‘Ministry of Defence ( DGI ) mer ( Alternate) . Instrument Manufacturers’ (Indie ) Prt ‘Ltd, New Delhi Sum S.C. Jars ( Alternate) SuntR. A. Padwawavnane Cena Mechanical Engieeing Revearch Istute rarer ‘Saar M. Passa Steel Authority of India Ltd (Rourkela Steel Plant), Rowekela Sunt N. Goranaxaramra ( Altenate) Sunt §. Rapwauaiouan Rational Aeronautical Laboratory (OSI), ‘Bangalore De. V. Smmivasax ( Almas) DV. Rao National Matallurgical Laboratory (CSIR ), ‘Jamshedpur Da D. J. Cxaxnavann: ( Altrnate} Sunt R.N.Sane Directorate General of Supplies and Dispomls, ‘New Del Sunt. K. Pawony ( Alternate) SuntD-N. Sanxan Ministry of Defence ( Ordnance Factories Board ), ‘Galeutta Sumi A, R. Basa ( Alrnate) ‘Sua FC. Samoa Directorate General of Civil Aviation, New Delhi Sie KE Swacarrar ley of Detoce (RAD J tH KeTawese fadian Register of Shipping, Bombay ‘Sunt S, Koatan (Altenate) “et pies: ‘Suu Yapnvm Soro Stoel Authority of ladia Ltd ( Bokaro Steel Plant ), ‘Boiare Suns P.N. Taswaray ( dllerste) Sant K. Raguavraonan, ‘Director General, ISt ( Eiefiie Member ) Direcior (Stue fe Met) Seertary Sunt Jaowouax Sriax Deputy Director ( Metals}, IST1S : 1599 - 1985 Indian Standard METHOD FOR BEND TEST (Second Revision ) ® FOREWORD .1 This Indian Standard ( Second Revision ) was adopted by the Indian Standards Institution on 28 February 1985, after the draft finalized by the Methods of Physical Tests Sectional Committee had been approved by the Structural and Metals Division Council. 0.2 This standard was first published in 1960 and was revised in 1974, While reviewing this standard in the light of the work done by ISO/TG 164 ‘Mechanical Testing of Metals’ at the international level, the Sectie nal Committee responsible for this standard decided to revise this standard 40 a8 to have a single Indian Standard on Method for bend test amalgamating three other Indian Standards on the subject. 0.2.1 This standard thus supersedes the following Indian Standards: IS : 1692-1974 Method for simple bend testing of steel sheet and strip less than 3 mm thick IS : 3260-1965 Method for bend test for copper and copper alloys IS: 4598-1968 Method for single bend test for aluminium and aluminium alloy sheet and strip of thickness between 02 mm and 7 mm 0.3 This standard is based on the International Standard ISO 7438-1985 “Metallic materials — Bend test’ issued by the International Organization for Standardization. 0.4 In reporting the results of test or analysis made in accordance with this standard, if the final value, observed or calculated, is to be rounced off, it shall be done in accordance with IS : 2-1960*, “Rules for rounding off numerical values ( revised). 318 +1599 - 1985 1. SCOPE LA This standard specifies the method of conducting bend test for determining the ability of metallic materials to undergo plastic defor- mation in bending. It applies to the bend test of test pieces taken from metallic products as specified in the relevant product standard. 1.2 This standard is not applicable to certain materials andjor products, for example tubes in full section or welded joints, for which other standards exist. 2. PRINCIPLE 2.1 The bend oot cons of mabunising swe pisoe of rund squats rectangular, or polygonal cross section to plastic deformation by bending, yrithout changing the direction of loading, until a specified angle of bend is reached. 22 The axes af the two legs of the test piece remain iu a plane perpendicular to the axis of bending. In the case of 180° bend, the two Jateral surfaces may, depending on the requirements of the material, standard, lie flat against each other or may be parallel at a specified 1g used to control thi 3, SYMBOLS AND DESIGNATIONS 3.1 Symbols and designations used in the bend test are shown in Fig. 1 and 2 and specified in Table 1. ‘TABLE 1 SYMBOLS AND DESIGNATIONS Snamous Dasionaziow Une « ‘Thicknen or diameter of text pices (oF am (a thown ia Glameter of the inscribed circle for Figures) pleces of polygonal eromsection ) ’ Width of vex piece mm L Length of tet pice am 1 Dineance between supports mm D Diameter of mandrel am . ‘Angle of bead degree * Internal radius of bend portion of test am piece afer beading 41S: 1599-1985 4. TEST EQUIPMENT 4.1 The bend test shall be carried out in testing machines or presses ‘equipped with the following devices: 8) Bending device with two supports and a mandrel a shown io ig. 1, b) Bending device with a V-block and a mandrel at shown in Fig. 2, and c) Bending device with a clamp as shown in Fig. 3. Fro. 1 Snepx Beno Test1S 1 1569 - 1985 Fro, 2. Beno Tesr sy Tax Use or V-Buock —— | VICE ee MANOREL VICE t Fro. 3. Beno Test Turovon ax Anore Over a Sprotmp Rapius* 4.2 Bending Device with Supports and a Mandrel 4.2.1 The length of the supports and the width of the mandrel shall be greater than the width or diameter of the test piece. The diameter of the mandrel is determined by the material standard. “The test piece Supports shall be rounded to a radius between I and 10 times the thick- ness of the test piece and shall be sufficiently hard ( see Fig. 1 ). 61S: 1599 - 1985 4.2.2 Unless otherwise specified, the distance between the supports / ‘hall be taken as approximately: t=D43a and shall not change during the bend test. 4.3 Bending Device with a V-Block 4.3.1 The tapered surfaces of the V-block shall form an angle of 180° — a ( see Fig. 2). 4.3.2 The edges of the V-block shall be rounded to a radius between 1 ‘and 10 times the thickness of the test piece and shall be sufficiently hard. 44 Bending Device with a Clamp — i hardness it may be equipped wit for applying force to the test piece ( see Fig. 3 ). 5. TEST PIECE 5.1 Round, square, rectangular or polygonal cross section test pieces are used in the test, Any areas of the material affected by shearing or fame cutting and similar operations during the Cutting of test pieces shall be removed. However, testing a test piece, the affected parts of which have not beea removed, is acceptable provided the resultant bend is satisfactory. 5.2 The edges of rectangular test pieces shall be rounded to a radius not exceeding one-tenth of the thickness of test pieces. ‘The rounding shall be made in such a way that no transverse, burrs, scratches or marks are formed which might adversely affect the test result. However, testing atest piece, the edges of which have not been rounded, is acceptable Provided the resultant bend is satisfactory. 5.3 Unless otherwise specified in the relevant standard, the width of the test piece shall be as follows: a) The same, when the width of the product is equal to or less than 20 mm; and b) When the width of a product is more than 20 mm: i) 20 + 5 mm for products of thickness less than 3 mm, and i) Between 20 and 50 mm for products of thickness equal to or greater than 3 mm. 54 Thickness of the Test Piece 5.4.1 The thickness of the test piece from sheets, strips and sections shall be equal to the thickness of the product to be tested. If the thick- ness of the product is greater than 25 mm, it may be reduced by machining one surface to not less than 25 mm, During bending, the unmachined side shall be the tension-side surface of the test Piece. 75.4.2 The round or polygonal cross section test piece shall be submitted to the bend test in the cross section equal to that of the product. In case the diameter ( for a round cross section ) or the inscribed circle diameter (for polygonal crom section) does not exceed 50 mm. When the diameter or the inscribed circle diameter, of the test piece exceed $0 mm up to and including 50 mm, it may be reduced to not less than 25 mm. When the diameter or the inscribed circle diameter, of the test piece exceeds 50 mm, it shall be reduced to not Jess than 23, mm (see Fig. 4). During bending, the urmachined side shall be the tension-side surface ( Fro, 4 Posrmion or Brxp Test Prece im Rounp on Porvoonat Sxcrions 5.5 In the case of forgings, castings and semifinished products, the Gimwensions of the text piece and sampling shall be at specified inthe relevant standard or by agreement. agreement but not in cases of dispute, test pieces of a greater hickteas Sed width than thoee specibed in 5°3 aid Bd may be subjected to the bend test. 5.7 The length of a test piece depends on the thickness of the test piece and the est equipment wed. 6 PROCEDURE 6.1 In general, the testis carried out at ambient temperature between 10 and 85°C, Tests carried out under controlled conditions shall be made ‘at a temperature of 23 + 5°C. 62 The bend test is carried out using one of the following methods specified in the relevant standard: 1a) That a specified angle of bend is achieved under the force and for the given conditions ( see Fig. 1, 2 and 3); b) That the legs of the test piece are parallel to each other at a specified distance apart while under the force ( see Fig. 6 ); and ©) That the legs of the piece are in direct contact while under the force ( see Fig. 7).18 : 1599 - 1985 63 In the bend test to a specified angle of bend, lay the test piece on the supports (se Fig. 1') of on the V-block ( s#¢ Fig. 2) and bend it in the middie between the supports by the action of a continuously increas- ing force. Apply the bending force slowly so as to permit free plastic flow of the material. 6.3.1 If it isnot possible to bend the test piece to the specified angle in the manner. deteribed in 6.3, complete the bend by pressing directly on the ends of the legs of the test piece (s4 Fig. 5 ). Fio, 5 Ben Tasr Txrovon 4 Srecmnap ANoLE 6.4 In the bend test to parallelism of the legs, the test piece may be bent first, as indicated in 6.3 and then placed between the parallel plates of the pres ( see Fig. 6 ) where it is further formed by application of a conti- nuously increasing force to obtain parallelism of the legs. The test may be carried out with or without the insert. ‘The thickness of the insert shall be defined in the relevant standards or by agreement. Cane fitoruate method of tat f chat of beading ever = mandeel 6.5 If specified, the test piece, after its preliminary bending, is further ‘bent between the parallel plates of the press, by application of a conti- uoully increasing force, t0 obtain direct contact between the legn of the teat piece ( see Fig. 7).So Fig. 6 Benp Tast Tarovox ax ANoLt oF 180° Over 4 SprcimnpjRaprut Fic, 7 Beno Test ro Far Coxprrion 7, INTERPRETATION OF RESULTS 7.1 The imerpretation of the bend test is carried out according to the requirements of the material standards. Wheh these requirements are not specified, absence of cracks visible without the use of magnifying aids is considered as the evidence that the test piece withstood the bend test. 7.2 The angle of bend, specified in material standards, is always considered as a minimum. If the internal radius of a bend is specified, it is considered as a maximum. 101S: 1599 - 1985 8. TEST REPORTS 8.1 The ten report shall include the following information: 4) Reference to this standard; b) Identification of the test piece (type of the material, cast number, direction of the test piece axis relative to a product, ete); ©) Shape and dimensions of the test piece; @) Test method; and ¢) Test result.