Method for evaluating inclusion types of steel and induced pitting trend thereof

Abstract

The invention relates to a method for evaluating inclusion types of the steel and an induced pitting trend thereof and belongs to the corrosion evaluation field. The inclusions of the steel are an important factor for induced pitting and other local corrosion. According to volt potential distribution of the inclusions of the steel, the types of the inclusions are discriminated, and the probabilityof induced pitting of the inclusions is evaluated. According to the method, the atomic force microprobe technology is employed for test, the types of the inclusions and the induced pitting difficultydegree can be clearly determined, moreover, the induced pitting phenomenon of the inclusions of the steel is further quantified, relative induced pitting probabilities of different inclusions can beacquired, corrosion resistance of the steel can be evaluated through utilizing the relative probabilities, and the evaluation result is of great importance for development of novel steel products, engineering structure design material selection and steel corrosion life evaluation .

Description

Technical field [0001] The invention belongs to the field of corrosion assessment, and particularly provides a method for identifying inclusion species and the probability of inducing pitting corrosion. Background technique [0002] Pitting corrosion is the most common type of corrosion in steel. Pitting corrosion can initiate and develop in a small area, accompanied by a high local corrosion rate, which will lead to structural failure and endanger the service safety and life of steel. Due to the hidden, random and sudden nature of local corrosion such as pitting, it is difficult to detect and evaluate the probability of pitting with conventional macro-electrochemical techniques. Inclusions in steel are an important factor in inducing local corrosion such as pitting corrosion. Different types of inclusions have different probabilities for inducing pitting corrosion. Therefore, a method for detecting the types of inclusions in steel and the probability of inducing pitting corrosi...

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Problems solved by technology

The pitting potential of different steel types in different environments may have a small difference. In addition, with the change of the environment, the pitting potential will change significantly. Therefore, the experimental results obtained by this method cannot quantitatively evaluate the inclusions. Types and their probability of inducing localized corrosion such as pitting

Due to the large number of inclusions in the steel, the types are often not single. This method is a macroscopic measurement. The measured pitting potential of all inclusions in the steel cannot distinguish the difference between the pitting corrosion induced by different types of inclusions.

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