The inhibition effect of imidazoline and diethylene triamine on the stress corrosion cracking of 08Cr2AlMo steel in H2S solution

08Cr2AlMo steel is a type of material developed especially for heat exchanger pipe bundle used under H2S condition in the recent years. In this paper, some researches were carried out on the stress corrosion cracking (SCC) susceptivity of 08Cr2AlMo steel in H2S water solution and the inhibition of imidazoline and diethylene triamine on the SCC by means of slow strain rate tensile test, scanning electron microscopy, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results indicate that 08Cr2AlMo steel is highly susceptible to SCC in saturated H2S solution for the fracture surfaces of specimen show typical quasi-cleavage fracture. The addition of both imidazoline and diethylene triamine into saturated H2S solution is effective on inhibiting the SCC. The inhibitors can reduce the potential of the cathodic hydrogen evolution, which prevents the penetration of hydrogen into the specimen effectively. Furthermore, inhibitors accelerate the formation of the chemically bonded film on the steel surface. It is also found that when the concentration of inhibitors is below 0.2%, there is no obvious inhibition effect on SCC, and the inhibition effect of diethylene triamine is better than that of imidazoline.