Study on Reloading Stress Relaxation Behaviour for High Temperature Bolted Steel
- Abdel-Fatah M. Hashem
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Designing and maintenance of mechanical elements is very important to clarify the effect of retightening (reloading) on stress relaxation behaviour of high temperature bolts. Experiments of stress relaxation simulates the real engineering problem of the long-term loosening of tightened bolts and other fasteners. Stress relaxation curves for a bolted steel 25 NiCrMo 8 are analyzed at three levels of test temperature (400, 450 and 500°C). The effect of the specified relaxation stresses on the reloading stresses behaviour is studied using five levels of the specified relaxation stress ratio (0.9, 0.8, 0.7, 0.6 and 0.5). Discussions are made on the relation between the testing time at each cycle and the number of loading with the variable of the specified relaxation stress ratio and the test temperature. The plastic strains accumulated during the course of the testing are analyzed and calculated by using empirical equation. Moreover, the apparent activation energy of relaxation behaviour which is determined as a relation of the testing time and of the specified relaxation stress ratio can be calculated.
- ASTM Standard, Definitions of Terms Relating to method of Mechanical Testing (E6) and (E238), ASTM Annual of Standard Part 10, 1997.
- Creep, Stress-Rupture and Stress Relaxation Testing (LFW/RWTH Aachen, 1997).
- C. Tanaka and T. Ohba, Stress Relaxation Behaviour of Type 316 Stainless Steel (1988).
- J.J. Marez, F. Bugnard, J.L. Lebrun, and G. Maeder, Residual Stress after Temper Rolling and Cold Forming of Steel Sheets—Influence on their Fatigue Behaviour (1988).
- J.K. Solberg and H. Thon, Materials Science and Engineering 75, 105-116 (1985).
- V. Sanchez-Galvez and M. Flices, Materials Science and Engineering 78, 1-8 (1986).
- E. Metcalfe and B. Nath, Materials Science and Engineering 67, 157-162 (1984).
- P. Delobelle, A. Mermet, and C. Oytana, Materials Science and Engineering 58, 1-13 (1983).
- D. Stone, H. Wilson, R.-C. Kuo, and Che-Yu Li, Scripta Metallurgica 21, 1559-1563 (1987).
- J. Filiprecki and A. van den Beukel, Scripta Metallurgica 21, 1111-1114 (1987).
- T.H. Alden, Scripta Metallurgica 21, 885-888 (1987).
- K. Okazaki and Y. Aono, Z. Metallkde., 68H.5, 368-374 (1977).
- C. Tanaka and T. Ohba, Transactions ISIJ 25, 80-88 (1985).
- Study on Reloading Stress Relaxation Behaviour for High Temperature Bolted Steel
Advanced Performance Materials
Volume 6, Issue 2 , pp 129-140
- Cover Date
- Print ISSN
- Online ISSN
- Kluwer Academic Publishers
- Additional Links
- activation energy
- loading number
- plastic strain
- specified relaxation stress
- Steel 25 NiCrMo 8
- stress relaxation
- test temperature
- Author Affiliations
- 1. Production Engineering & Design Department, Faculty of Engineering, Minia University, 61111, Minia, Egypt