Analysis of various metal structures under a metallurgical microscope
Metallographic obligors have been qualitatively depicting the microstructure characteristics of metal materials through microscopic observation on the polished surface of metallographic specimens for many years, or evaluating the microstructure, grain size, non-metallic additives, and phase particles by comparing them with various standard images. This method has low accuracy and subjectivity in evaluation, and the reproducibility of the results is also unsatisfactory. Moreover, the measurement results are determined on the two-dimensional plane of the polished surface of metallographic specimens, and there is a certain gap between the measurement results and the description of the real microstructure in three-dimensional space. The emergence of modern stereology has provided people with a science of extrapolating two-dimensional images to three-dimensional space, which links the data measured on a two-dimensional plane with the theoretical microstructure, size, quantity, and distribution of metal materials in three-dimensional space. It can also establish an inherent connection between the three-dimensional structure, size, quantity, and distribution of materials and their mechanical functions, providing reliable analytical data for scientifically evaluating materials.
Due to the uneven distribution of visible microstructure and non-metallic additives in metallic materials, the determination of any parameter cannot be determined solely by measuring one or several fields of view with the human eye under a microscope. It is necessary to use accounting methods to perform many accounting tasks on a sufficient number of fields of view in order to ensure the reliability of the measurement results. Assuming that visual evaluation is solely based on human eyes under a microscope, its accuracy, consistency, and reproducibility are poor, and the measurement speed is slow, with some even being unable to proceed due to excessive workload. The image analyzer replaced human observation and accounting with electronic optics and computer skills to improve the skills of elders. It can quickly and accurately perform meaningful measurements and data processing, and has high accuracy, good reproducibility, and avoids the influence of treatment factors on metallographic evaluation results. It is also simple to operate and can directly print measurement declarations. At that time, it had become an indispensable means in quantitative metallographic analysis.
Microscope image analyzer is a powerful tool for quantitative metallographic research of materials, and it is also a good assistant for daily metallographic inspection. It can avoid subjective errors caused by manual evaluation and also avoid the phenomenon of tearing. Although it is not possible or necessary to use an image analyzer every time in daily metallographic inspection, when there are abnormalities in product quality or the metallographic structure level is between qualified and unqualified and cannot be distinguished, an image analyzer can be used for quantitative analysis to obtain accurate results and ensure product quality. The application of image analyzers in metallographic analysis has expanded the detection items of metallographic examination, promoted the improvement of detection level, and has been beneficial in enhancing the quality of detection personnel.
