Temperature dependence of thermo‐mechanical fatigue behaviour of a martensitic 5 % chromium steel
Résumé
Strain‐controlled out‐of‐phase thermo‐mechanical fatigue (OP TR;IF) tests were performed in air on a tempered martensitic 5 % chromium hot work tool steel (X38CrMoV5). Thin‐walled tubular specimens were used. The effect of the minimal and maximal temperatures of the thermal cycle on the stress‐strain behaviour was assessed. The mechanical strain range was unchanged. Under the test conditions examined, the influence of the minimal temperature was very slight while a strong effect of the maximal temperature on the cyclic softening was observed. Increasing maximal temperature increases dramatically cyclic softening. It was observed that when the maximal temperature is near or above the second tempering temperature, steel softening process increases.