Stress corrosion cracking of rotor steels in carbonate/bicarbonate and sodium hydroxide solutions

Johann Rechberger
In this study, the stress corrosion behavior of 3.5%NiCrMoV and 1%CrMoV steels was investigated. Tests were conducted at 95°C in carbonate/bicarbonate and sodium hydroxide solutions. Results from slow strain rate tensile tests and fracture mechanics experiments were compared. A new, easily machinable, specimen geometry for fracture mechanics experiments was tested. The influence of pH, potential, microstructure and inclusions were studied. Stress corrosion cracking (SCC) was found with all
more » ... found with all three steels in the 3.5M NaOH solution at active, passive and transpassive potentials. In the 1M carbonate/ bicarbonate solutions, the 1%CrMoV steels showed very severe cracking only during slow strain rate experiments. No major difference in cracking behavior was found between a regular 3.5%NiCrMoV steel and a super clean 3.5%NiCrMoV steel with low Mn and Si content. In acidic CO₂/H₂O environments, crack tip blunting was observed due to strong dissolution processes.
doi:10.14288/1.0078565 fatcat:gcbj6onaunbfljzoenalpdb6wm