Image Classification Evaluation And Application Of 316L Stainless Steel Passivation Film Damage

316L austenitic stainless steel is widely used in nuclear power,ocean engineering and other fields because of its excellent corrosion resistance and good comprehensive mechanical properties.In the engineering manufacturing and application stage,the integrity of the passive film is damaged by iron pollution,scratches,etc.,which affects its corrosion resistance and induces rust.The on-site inspection of the integrity of the passive film on the surface of austenitic stainless steel is one of the engineering quality inspections.Link.In the early stage,the research group proposed an o-phenanthroline color detection method,which has the characteristics of high sensitivity and strong adaptability.In order to meet the requirements of the current development trend of intelligent detection and analysis technology,how to grade and evaluate the passivation film based on the color detection has become a topic of interest today.For this article,the integrity of the stainless steel passivation film based on redness conversion Few reports on color detection and grading evaluation.This paper uses the orange-red characteristic of o-phenanthroline to carry out the image analysis study of the damage of the passivation film,compares the color development characteristics under the conditions of iron pollution and the passivation film scratch,and uses digital image processing technology combined with red chromaticity.The classification of iron contamination and passivation film scratches was verified,and the classification evaluation was verified in the welding experiment,and the correlation between color development and corrosion resistance was established.The main findings are as follows:(1)For the observation of the color characteristics of iron contamination and the scratches of the passivation film,combined with the analysis of the three-dimensional reconstruction map and the distribution histogram,it is found thatThe color rendering value caused by iron pollution can reach a*=18 or more,and the color rendering value of the passivation film scratch is a*<18.For the chromaticity ratio Cra,the histograms of iron contamination and passivation film scratches all have a sharp transition at a*=3.Observe the area where a*<3,the surface does not show color,and get a*=3 It is the dividing line between the passivation non-color development area and the color development,and a*=18 is the color development boundary between iron contamination and passivation film scratches.(2)For iron pollution and passivation film scratch color detection and grading experiments,the results show that: when a*<3,it is a passivation qualified sample.On this basis,iron pollution grading experiments are carried out,which is divided into 5 levels.At the same time,under the conditions of dispersion and accumulation,their color integral and area integral have corresponding linear relationships,and the more iron powder content,the greater the slope of the corresponding linear relationship.For the passivation film,it is not only necessary to consider the color rendering value,but also the color rendering area.For the color rendering value,combined with the iron powder color grading experiment,when a*>18,you can consider including iron Pollution situation: The grading in this experiment is between a*: 3-18.When grading,it is necessary to consider the proportion of color rendering area and color rendering integral to classify,and it is divided into 6 levels.(3)For the verification grading evaluation experiment,under light grinding conditions,there is a non-polluting weld with oxide scale compared with iron-contaminated welds,and the passivation quality of the passivation film is reduced.Under deep grinding conditions,the color development time of welds is prolonged due to the presence of oxide inclusions and the increase of iron contamination content.In the grading evaluation and verification,it can be found that the verification results of the color rendering parameters are in full compliance with the set grading range.The color grading verification of the failed stainless steel pipe welds showed that there were iron contamination,rust,and friction scratches on the surface,and the color rendering parameters Cra and Sra obtained were in full compliance with the set grading results.The results shown by the electrochemical impedance diagram and the dynamic polarization curve are consistent with the results of the color detection and characterization.The ophenanthroline color detection method can certainly characterize the corrosion resistance of the welded samples.