Disclosure to Promote the Right To Information

Transcription

1 इ टरन ट म नक Disclosure to Promote the Right To Information Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public. ज न1 क अ+धक र, ज 1 क अ+धक र Mazdoor Kisan Shakti Sangathan The Right to Information, The Right to Live प0र 1 क छ ड न' 5 तरफ Jawaharlal Nehru Step Out From the Old to the New IS (2005): Sintered metal materials, excluding hardmetals - gatigue test pieces [MTD 25: Powder Metallurgical Materials and Products]! न $ एक न' भ रत क +नम-ण Satyanarayan Gangaram Pitroda Invent a New India Using Knowledge! न एक ऐस खज न > ज कभ च0र य नहB ज सकत ह ह Bhartṛhari Nītiśatakam Knowledge is such a treasure which cannot be stolen

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4 W wfhwm $RmlawT3i?T Indian Standard SINTERED METAL MATERIALS, EXCLUDING HARDMETALS FATIGUE TEST PIECES ICS (Q BIS 2005 BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI Apri/ 2005 Price Group 4

5 Powder Metallurgical Materials and Products Sectional Committee, MTD 25 NATIONAL FOREWORD This Indian Standard which is identical with ISO 3928: 1999 Sintered metal materials, excluding hardmetals Fatigue test pieces issued by the International Organization for Standardization ( ISO ) was adopted by the Bureau of Indian Standards on the recommendations of the Powder Metallurgical Materials and Products Sectional Committee and approval of the Metallurgical Engineering Division Council. In this adopted standard, some terminology and conventions are, however, not identical to those used in Indian Standards. Attention is especially drawn to the following: a) Wherever the words International Standards appear referring to this standard, they should be read as Indian Standard. b) Comma (, ) has been used as a decimal marker while in Indian Standards, the current practice is to use a point (. ) as the decimal marker. In reporting the results of a test or analysis made in accordance with this standard, if the final value, observed or calculated, is to be rounded off, it shall be done in accordance with IS 2:1960 Rules for rounding off numerical values ( revised).

6 Indian Standard SINTERED METAL MATERIALS, EXCLUDING HARDMETALS FATIGUE TEST PIECES 1 Scope This International Standard specifies: the die cavity dimensions used for making fatigue test pieces by pressing and sintering, together with certain dimensions of the test piece obtained from such a die; the dimensions of the test pieces machined from sintered and powder forged materials. This International Standard is applicable to all sintered metals and alloys, excluding hardmetals. 2 Pressed and sintered test pieces for fatigue test by reverse bend and axial testing 2.1 General The pressed and sintered piece may also be subjected to further treatment, such as sizing, polishing or heat treatment. If such treatments are applied, they shall be stated in the test report. In a metallographically examined cross section of a test piece, in the gauge region, the piece shall show no micro-lamination greater than 0,25 mm in length. Corners shall be broken in the gauge area. 2.2 Test piece specification: unnotched Figure 1 a) shows a drawing of the unnotched test piece. The flatness and parallelism of 0,1 mm are mandatory. The other dimensions are advisory. Burrs shall be avoided. 2.3 Test piece specification: notched Figure 2a) shows a drawing of the notched test piece. The flatness and parallelism of 0,1 mm are mandatory. The other dimensions are advisory. Burrs shall be avoided. The tooling radius 5,5 mm of the die is subject to wear, then the corresponding radius dimension of the test piece shall be reported. 3 Die specifications 3.1 General The die should preferably be of hardmetal and its surface finish shall be such as to allow compression of test pieces under normal conditions. The die may include a small exit taper to facilitate ejection and avoid cracks or microlaminations in the test pieces. Die cavity may be tapered 0,01 per side to aid ejection. Die bore may be enlarged by 0,5 YO for tooling to be used for repressing. The die should be well supported with shrink rings (of internal diameter 120 mm410 o mm), so as to minimize lateral expansion during compacting. Such support decreases the possibility of cracking of the specimen at ejection. To reduce the incidence of cracks in the specimen, it is recommended to use top punch hold down during ejection. 1

7 3.2 Die specifications for unnotched test pieces The recommended die cavity is shown in Figure 1 b). 3.3 Die specifications for notched test pieces The recommended die cavities are shown in Figure 2 b). 4 Machined test pieces Many types of machined test piece may be used according to the different known procedures of fatigue testing (rotating beam, axial loading, reverse bending, etc.) except that it is not recommended to machine test pieces with square or rectangular cross sections. An example of the rotating beam piece, is given in Figure 3. Figure 4 shows an example of a test piece for axial loading fatigue testing. The machined test pieces shall be ground over their active length, using a diamond wheel, and lapped longitudinally in order to remove all traces of circumferential scratches. Final polishing should be in the longitudinal direction (no circumferential scratch lines should be visible); try to achieve a smooth blend with no undercut. Cold work and stresses from machining significantly increase the yield strength of austenitic stainless steel. Annealing or stress relieving may be required to duplicate the as-sintered structure. Any such heat treatment shall be reported. Practical experience with fatigue testing of carefully machined test pieces of circular cross section has shown that their endurance limits may be 20 YO to 30 YO higher than those obtained on unmachined, as-moulded test pieces with square or rectangular cross sections. Use progressively lighter machining passes to minimize residual stresses. Diameter in gauge length should be uniform within t 0,025 mm. 5 Identification of test pieces For the identification of test pieces, the following shall be stated: a) b) c) d) e) f) 9) h) i) j) reference to this International Standard, i.e. ISO 3928; type of material; density of test piece; dimensions of test piece (thickness); when pressed and sintered test pieces are made according to clause 2, the nature of any finishing treatment shall be stated and also, preferably, the material and surface finish of the compacting too( form of test piece, i.e. figure numben die material, i.e. tool steel or hardmetalkarbide; whether as-sintered or heat treated; hardness of test piece according to heat treatment; bottom of notch radius used on notched test piece, Figure 2. 2

8 Dimensionsin millimetres N l i I I I I I I [//10,1} a) Test piece G I, b) Die Figure 1 Unnotched test piece and compacting die for use with unnotched fatigue test pieces 3

9 Dimensionsin miliimetres 4 I A 1;1 [ I I//lojlt ( m a) Test piece b) Die The stress concentration factor Kt depends upon radius R, as follows: Y r Kt Kt axial loading reverse bending 0,9 * 0,02 2,4 1,8 0,45 * 0,02 3,2 2,4 Figure 2 Notched test piece and compacting die for use with notched fatigue test pieces

10 Dimensionsin millimetres Figure 3 Machined rotating beam fatigue test piec6 m N- a $ * Q) y / a 15,5 to,l 11 ~1 15,5 fo,l I 75 *1 I Figure 4 Machined axial loading test piece 5

11 Annex A (informative) Remarks ISO 1099, ISO 1352 and ISO 1143 define the general principles of fatigue testing of metals. These principles are applicable to sintered metals with the following remarks. a) b) c) d) e) Sintered metals are characterized by the presence of pores, which are unavoidable stress raisers. Porosity reduces the actual cross section of the specimen to be tested; this means that the nominal stress values, as calculated from the usual formulae, are smaller than the true stresses. In most cases, the presence of interconnected pores opening to the surface makes sintered pieces much more sensitive to environmental conditions than pore-free materials are; porous products can be affected by internal corrosion processes not only during fatigue testing, but also before the test therefore such test pieces must be stored more carefully than pore-free test pieces. The surface state of a test specimen or PM part significantly influences its fatigue behavioun therefore, in order to obtain a proper transmission of fatigue data obtained with specimens used to assess the fatigue behaviour of PM component, the surface states of specimens and components must be comparable. Machining by milling or turning densifies the surface and introduces compressive residual stresses. This leads. to a much higher fatigue strength compared to the non-machined state. (A grinding operation is much softer.) Therefore, surface machining of test specimens should be carried out only in cases where the critical area of a PM part is also machined. However, as most PM parts have non-machined surfaces, evaluation of the fatigue behaviour should preferably be performed by transmission of fatigue data obtained with non-machined surfaces.

12 Bibliography [1] ISO 296, Machine tools Self-holding tapers for tool shanks. [2] ISO 1099, Mets/s Axial fatigue testing. [3] ISO 1143, Metals Rotating bar bending fatigue testing. [4] ISO 1352, Stee/ Torsions/ stress fatigue testing.

13 Bureau of Indian Standards BIS is a statutory institution established under the Bureau of/ndian StandardsAct, 1986 to promote harmonious development of the activities of standardization, marking and quality certification of goods and attending to connected matters in the country. Copyright BIS has the copyright of all its publications. No part of these publications maybe reproduced in any form without the prior permission in writing of BIS. This does not preclude the free use, in the course of implementing the standard, of necessary details, such as symbols and sizes, type or grade designations. Enquiries relating to copyright be addressed to the Director (Publications), BIS. Review of Indian Standards Amendments are issued to standards as the need arises on the basis of comments. Standards are also reviewed periodically; a standard along with amendments is reaffirmed when such review indicates that no changes are needed; if the review indicates that changes are needed, it is taken up for revision. Users of Indian Standards should ascertain that they are in possession of the latest amendments or edition by referring to the latest issue of BIS Catalogue and Standards : Monthly Additions. This Indian Standard has been developed trom Doc : No. MTD 25 ( 4377 ). Amendments Issued Since publication Amend No. Date of Issue Text Affected Headquarters: BUREAU OF INDIAN STANDARDS Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Delhi Telephones : , , Website : www. bis.org. in Regional Offices : Telephones Central : Manak Bhavan, 9 Bahadur Shah Zafar Marg NEW DELHI 11OOO2 { Eastern : Northern : Southern : Western : Branches: 1/14 C. 1. T. Scheme Vll M, V. 1. P. Road, Kankurgachi , KOLKATA { , SCO , Sector 34-A, CHANDIGARH C. 1. T. Campus, IV Cross Road, CHENNAI { { , , Manakalaya, E9 MlDC, Marol, Andheri (East) , MUMBAI { , Al-f MEDABAD. BANGALORE. BHOPAL. BHUBANESHWAR. COIMBATORE. FARIDABAD. GHAZIABAD. GUWAHATI. HYDERABAD. JAIPUR. KANPUR. LUCKNOW. NAGPUR. NALAGARH. PATNA. PUNE. RAJKOT. THIRUVANANTHAPU RAM. VISAKHAPATNAM. Printed at New India Printing Press, Khurja, India