The purpose of this paper is to clarify the influence rule of Cl- concentration changes on the corrosion resistance of super 13Cr Martensite stainless steel.The influence of Cl- concentration on the corrosion potential of super 13Cr was compared and analyzed by electrochemical potentiometric test.In addition, the influence of Cl- concentration on the tensile strength, elongation and stress corrosion sensitivity index(ISSRT)of super 13Cr martensitic stainless steel under a certain slow tensile rate in saturated CO2 solutions were studied by the means of slow strain rate tensile(SSRT)SCC test, stress-strain curve(σ-ε)and scanning electron microscope(SEM).Furthermore, the fracture characteristics of the materials were researched by the fracture morphology.Results showed that in the saturated CO2 solution with Cl-concentration lower than 60 g/L, super 13Cr had little change in strength and toughness compared with that in the air, which belonged to the ductile fracture mode; with the increase of Cl- concentration, the fracture life and elongation of the material decreased gradually; the fracture mode of the material changed from the ductile fracture to the ductile brittle mixed fracture mode; when Cl- concentration increased to 90 g/L, the second crack began to appear at fracture side.When Cl- concentration was higher than 120 g/L, the pitting potential of the material decreased significantly, the pitting sensitivity increased, and the pitting phenomenon appeared on the side of the fracture, which further promoted the stress corrosion cracking.
ZHAO Xue-hui, LIU Jun-lin, ZENG Rui-hua, XU Cong-min, XU Xiu-qing
. Effect of Cl- Concentration on the Stress Corrosion Sensitivity of Martensitic Stainless Steel in Saturated CO2 Solution[J]. Materials Protection, 2021
, 54(1)
: 36
-44
.
DOI: 10.16577/j.cnki.42-1215/tb.2021.01.006
