Phase transformation and impact properties in the experimentally simulated weld heat-affected zone of a reduced activation ferritic/martensitic steel

摘要

In this work, the phase transformation and impact properties in the weld heat-affected zone (HAZ) of a reduced activation ferritic/martensitic (RAFM) steel are investigated. The HAZs were experimentally simulated using a Gleeble simulator. The base steel consisted of tempered martensite through normalizing at 1000 degrees C and tempering at 750 degrees C, while the HAZs consisted of martensite, delta-ferrite and a small volume of autotempered martensite. The impact properties using a Charpy V-notch impact test revealed that the HAZs showed poor impact properties due to the formation of martensite and delta-ferrite as compared with the base steel. In addition, the impact properties of the HAZs further deteriorated with an increase in the delta-ferrite fraction caused by increasing the peak temperature. The impact properties of the HAZs could be improved through the formation of tempered martensite after post weld heat treatment (PWHT), but they remained lower than that of the base steel because the delta-ferrite remained in the tempered HAZs. (C) 2014 Elsevier B.V. All rights reserved.