Evaluation of damage of steam pipeline steel using local approach to fracture

Abstract

In the paper, the level of damage of steam pipeline steel after about 100,000 hours at 540 degrees C (1004 degrees F) under pressure of 42 bars (609 PSI) is analyzed. Material degradation is estimated using a combined experimental and numerical procedure based on micromechanical or local approach to fracture. Detailed analysis is conducted on the samples taken from exploited used steel and from unused new steel of the same designation. Damage parameter void growth ratio - is determined using round notched specimens, (including various notch radii). A comparison of the values for critical void growth ratio, computed for tested steels is made. Based on the values obtained, the possibility of prolongation of the operating life Of used steel is discussed.