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1、INTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION .MEX the tolerance on diameter d shall be + 0,05 mm. 1 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/28/2007 07:52
2、:16 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO1352-1977 (E) For the purpose of calculating the torque to be applied to obtain the required stress, the actual diameter of each test piece shall be measured to an accuracy of 0,Ol mm. Care should be taken during the me
3、asurement of the test piece prior to testing that the surface is not damaged. In the case of a cylindrical test piece having a parallel test section, this test section shall have a length not greater than W and it shall be parallel within 0.02 mm. The transition blending radius at the end of the par
4、allel test section shall have a radius not less than 3d. In the case of a test piece having a test section formed by a continuous radius, this radius shall be not less than 5d. a) -i b) FIGURE 1 - Forms of test piece FIGURE 2 I- rypicel test piece ends 2 6 PREPARATION OF TEST PIECE 6.1 General It is
5、 essential that any cutting or machining operation required, either to rough out the test piece from the blank, or to finish it to size, shall not alter the metallurgical structure or the mechanical properties of the test piece or induce substantial residual surface stress. Care should be taken in t
6、he preparation of the ends of the test piece to ensure that the requirements of clause 7 can be met. 6.2 Turning It is recommended that the following procedure be adopted : 6.2.1 In rough turning the test piece from a diameter x + 5 mm (X will generally be the diameter, d, plus a suitable allowance
7、for surface finishing) to x + 0,5 mm, a succession of cuts of decreasing depth should be made, the recommended depths of cuts being : I,25 mm, 0.75 mm and 0,25 mm. 6.2.2 From a diameter of x + 0,5 mm to x, a further succession of cuts of decreasing depths should be made, the recommended depths of cu
8、ts being : 0,125 mm, 0,075 mm and 0,05 mm, using for these finishing cuts a feed not exceeding 0,06 mm per revolution. 6.3 Grinding For test pieces in material which cannot be readily turned, it is recommended that the finishing operations be carried out by grinding. If the strength properties of th
9、e material are developed by heat treatment, this heat treatment may be carried out after rough turning to a diameter of x + 0,5 mm. The test piece should then be ground to size. A succession of cuts of decreasing depth should be made, the recommended values being : - 0,030 mm depth of cut to 0,l mm
10、oversize; - 0,005 mm depth of cut to 0,025 mm oversize; - 0,002 5 mm depth of cut to size. 6.4 Surface finishing After the test section has been machined or ground to nominal dimensions, it shall be polished either by hand or by machine, using successively finer grades of abrasive papers or cloths.
11、The polishing should generally be in a circumferential direction, although intermediate stages may be done in any direction, to ensure that scratches made by the coarser grades of abrasive papers, or cloths, are removed. The direction of the final polishing should mainly be circumferential. , Copyri
12、ght International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/28/2007 07:52:16 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 1352-1977 (El e) the range of relative humidity,
13、if this is outside the range of 50 to 70% (the range of relative humidity should be measured every day throughout the duration of the test); f) any deviation from the specified conditions during the test; g) the criterion of failure, if other than complete failure of the test piece, for example IO o
14、r IO* cycles. 4 1 In the majority of fatigue determinations the criterion of failure is either the occurrence of visible fatigue cracks or a complete fracture. It should be noted, however, that for particular applications other criteria, for example plastic deformation of the test piece or rate of c
15、rack propagation, may be adopted to determine the end of the test. If required, and particularly if low frequencies and high stresses are employed, the criterion of failure shall be the subject of agreement. 2 Test results may be presented graphically in one of the forms given in ISO/R 373. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/28/2007 07:52:16 MDTNo reproduction or networking permitted without license from IHS -,-,-
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