BS ISO 7905-3 pdf free download
BS ISO 7905-3-2019 pdf free download.Plain bearings — Bearing fatigue Part 3: Test on plain strips of a metallic multilayer bearing material.
This document specifies a method for the determination of the endurance limit in fatigue of plain stripsof multilayer bearing materials. Additionally, it provides the opportunity of studying the influence on the strips of hydraulic pressure and variable temperature.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
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4 Test specimens
The test specimens shall be flat thin strips of rectangular cross‑section to the dimensions shown in
Figure 1. To avoid fracture starting at the clamped portion, the edges shall be carefully chamfered by grinding and the test section shall be contoured as shown in Figure 1.
For a multilayer bearing material, the layer dimensions of the test specimen shall be representative of the manufacturing sequence and the test specimen shall be finished to the same surface texture. Care should be taken before and during the test not to damage the surface mechanically or by corrosion. The deficiency of this test method lies in the absence of possible residual stress associated with the bearing manufacturing process.
6 Evaluation and presentation of test results The measurement instrumentation for the proposed test principle is illustrated in Figure 3. The endurance limit stresses should be presented in the form of σ el ‑N curves at predetermined temperature (±2 °C) against a detailed description of the bearing material. Normally, σ el ‑N curve testing is terminated for practical considerations at 50 × 10 6 stress cycles. The endurance limit stress may be quoted at a specified number of cycles, e.g. 3 × 10 6 , 10 × 10 6 , 25 × 10 6 or 50 × 10 6 . A specimen without failure during fatigue testing to a specified endurance should be identified in the report. Due to the scatter of test results normally experienced and the statistical nature of the fatigue limit, it is recommended that the results be evaluated on the basis of a statistical method. The endurance limit stress may be presented by means of the Haigh diagram which plots stress amplitude against mean stress. Metallographic examination provides detailed evidence of the damage mechanism, corrosive attack and diffusion resulting from thermal effects.BS ISO 7905-3 pdf download.
