Microstructure and aging influence on the mechanical properties of high-voltage poles
Keywords:ageing, corrosion, microstructure, mechanical properties
High-voltage poles made in 1956 had to satisfy the cross-sectional geometry related standard (GOST 8509-57 confirmed later). However, the stricter requirements weren’t applied for the microstructure. In this paper a strength analysis of the pillars’ material is provided. The technological specificities of profile manufacturing were mostly determined by differences in mechanical properties influenced by differences in microstructures of pillars’ material investigated. Although the confirmed standard of steel CT3 (GOST 380-71) had new requirements and clear criteria of microstructure acceptance but made pillars with the non-homogeneous microstructure remained standing. The differences in microstructural components create conditions for appreciable differences in mechanical properties such like yield stress and ultimate stress, fracture strain. In this paper, the limits of elastic and plastic strains are identified in order to quantify the changes in elastic and plastic properties with the differences in their intensity for selected step-like stress range. Corrosion depth and width play the large role and ones often determine the fracture location of samples. The end of this work is dedicated to conclusion based on the relation of experimental part and analytical calculations presented.