BS ISO 1143:2021 pdf download – Metallic materials — Rotating bar bending fatigue testing

BS ISO 1143:2021 pdf download – Metallic materials — Rotating bar bending fatigue testing Experience has shown that a ratio of at least 2:1 between the cross-sectional areas of the gripping regions and the test portion of the specimen is recommended. The grips which do not lead up to large stress-concentration area are recommended. In tests on certain materials, a combination of high stress and high speed may cause excessive hysteresis heating of the specimen. This effect may be reduced by subjecting a smaller volume of the material or by decreasing the test frequency (see 10.3). If the specimen is cooled, the test medium should be reported. 6.2 Dimensions of specimens All the specimens employed in a test series for a fatigue-life determination shall have the same size, shape and tolerance of diameter. For the purpose of calculating the force to be applied to obtain the required stress, the actual minimum diameter of each specimen shall be measured to an accuracy of 0,01 mm. Care shall be taken during the measurement of the specimen prior to testing to ensure that the surface is not damaged. On cylindrical specimens subject to constant bending moment (see Figures 4 and 5), the parallel test section shall be parallel within 0,025 mm. For other forms of cylindrical specimen (see Figure 1), the parallel test section shall be parallel within 0,05 mm. For material property determination, the transition fillets at the ends of the test section should have a radius not less than 3d. For hourglass-type specimens, the section formed by the continuous radius should have a radius not less than 5d. Figure 8 shows the shape and dimensions of a typical cylindrical specimen. The recommended values of d are 6 mm, 7,5 mm and 9,5 mm. The tolerance of diameter should be 0,005d. Figure 9 shows a typical hourglass specimen suitable for fatigue testing at elevated temperature. 7 Preparation of specimens 7.1 General In any rotating bar bending fatigue test program designed to characterize the intrinsic properties of a material, it is important to observe the following recommendations in the preparation of specimens. A possible reason for deviation from these recommendations is if the test program aims to determine the influence of a specific factor (surface treatment, oxidation, etc.) that is incompatible with the recommendations. In all cases, any deviation shall be noted in the test report. 7.2 Selection of the specimen and marking...