FRACTURE TOUGHNESS AND CRACK RESISTANCE OF STEAM PIPELINE STEEL IN INITIAL AND USED STATES

摘要

Premature fracture of steam pipelines from 14MoV6 3 steel designed for 100,000 h service life at 540 deg C has been studied. Test specimens are manufactured from steel in the initial state and after 117 h of operation. Application of the local approach to fracture and the metallographic analysis, in addition to classical methods (tensile, crack resistance, and fatigue strength tests), provided a more precise evaluation of steel properties degradation due to elevated temperatures and stresses. Urgency of further development of the local approach to predicting material fracture after long-term operation at high temperatures has been substantiated.