Mechanical-Metallurgical Failures
These types of failures originate from the mechanical properties of metallic materials, which are linked to their specific crystal structure, grain sizes, and types of dedicated phases formed, among other factors. Parameters such as hardness, yield strength, and ductility tend to change based on process variables like elevated temperature, duration of exposure, and the presence of a corrosive environment. Consequently, the mechanical properties of metals gradually deteriorate over time, leading to failures. Predicting or quantitatively measuring these types of failures is challenging due to the multidimensional correlations between various parameters and the specific structure of metallic crystals.
Stress Relaxation Cracking (SRC) is arguably one of the most underrated cracking phenomena. Sudden equipment and pipeline failures at high temperatures, often occurring shortly after start-up, have typically been misattributed to overheating, creep, or other high-temperature damage modes. This chapter provides comprehensive information on SRC, including its recognition during failure analysis and strategies for its prevention.