LOW-CYCLE FATIGUE PROPERTIES OF 8CR-2WVTA FERRITIC STEEL AT ELEVATED-TEMPERATURES

The effects of test temperature and tension holding on the fatigue pro perties of reduced activation ferritic/martensitic 8Cr-2WVTa (F-82H) s teel were investigated by conducting low cycle fatigue tests at temper atures ranging from RT to 650 degrees C under the axial strain-control led condition with strains ranging from 0.5% to 2.0%. Fatigue life dat a were formulated as strain-life equations. A large reduction in the f atigue life was recognized at temperatures above 600 degrees C. Soften ing without showing a saturated region was observed in the fatigue sof tening curves at temperatures above 600 degrees C. Tension holding dur ing fatigue tests reduced the fatigue life at 400 degrees C, 500 degre es C and 600 degrees C. The microstructural examination showed that th e large softening during cycle was associated with carbide (M23C6) coa rsening and Laves phase (Fe2W) precipitation at 600 degrees C. (C) 199 8 Elsevier Science B.V. All rights reserved.