A method for testing susceptibility to intergranular corrosion of austenitic stainless steel

Abstract

The invention discloses a method for detecting intercrystalline corrosion sensitivity of austenitic stainless steel. The method comprises the following steps: firstly preparing an austenitic stainless steel sample to be detected into a working electrode to be detected, establishing a three-electrode standard system by adopting the working electrode to be detected, performing the potentiodynamic scanning by adopting an electrochemical measurement instrument, and observing a corrosion shape appearance figure of the austenitic stainless steel sample to be detected in the working electrode to be detected after the potentiodynamic scanning treatment, wherein electrolyte in the three-electrode standard system is prepared by mixing sulfuric acid, sodium chloride and sodium sulfate, the concentration of the sulfuric acid in the electrolyte is 0.8 to 1.2 mol / L, the concentration of the sodium chloride is 0.4 to 0.6 mol / L, and the concentration of the sodium sulfate is 0.1 to 1.5 mol / L. According to the method, different sensitivities of the austenitic stainless steel can be intuitively distinguished by virtue of the dimensional variation of a crystal interface in the corrosion shape appearance figure so as to judge the intercrystallline corrosion sensitivity of the austenitic stainless steel.

Description

technical field [0001] The invention relates to the application field of austenitic stainless steel, in particular to a method for testing the susceptibility to intergranular corrosion of austenitic stainless steel. Background technique [0002] Intergranular corrosion is one of the common forms of corrosion in austenitic stainless steel. Once intergranular corrosion occurs in austenitic stainless steel, its strength will be basically lost, but its appearance will hardly change and it will be difficult to identify. Therefore, it is easy to cause major corrosion failure accidents and cause huge economic losses. [0003] The electrochemical potentiodynamic reactivation method (EPR method) is a commonly used electrochemical method to evaluate the intergranular corrosion susceptibility of austenitic stainless steel. Its detection process includes two parts: activation process and reactivation process. The activation process is the forward sweep process, which is mainly to form...

AI Technical Summary

Problems solved by technology

For austenitic stainless steels with different susceptibility to intergranular corrosion, the size of the grain boundary in the corrosion topography diagram after applying the existing electrochemical potentiodynamic reactivation method is basically the same, and it is difficult to directly judge the sensitivity; The susceptibility to intergranular corrosion of austenitic stainless steel can only be evaluated by calculating the sensitization value

This results in the dependence on the sensitivity value when judging the susceptibility to intergranular corrosion of different austenitic stainless steels. If the data is wrong, it will directly affect the judgment result. If the data is lost, additional repetitive work will be required.

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