Metal Microstructure Examination

Metal Metallographic Examination

Metallographic examination is a very important and necessary testing method for metal engineering products, which can directly determine the product quality during the manufacturing process and in use. Therefore, metallographic examination of metal seldom fails to be done.

Metallographic examination is the use of transmitted light and metallographic microscope to observe the sample, to obtain macro and micro examination of the sample. Micro-examination is also known as optical microscopic examination. Optical microscopic examination, through observation, can obtain microscopic morphology of the sample, further analyze the macrostructure of the sample, such as grain size and distribution, presence, impurities and inclusions, matrix structure and other information, so as to judge the structure and mechanical performance of the sample .

Metallographic examination is usually divided into the following five procedures: sample preparation, grinding and polishing, etching, observation and auxiliary inspection (physical, chemical and instrumental methods).

Sample preparation: The sample for metallographic examination is usually cut from the original material, or the sample after heat treatment. Before metallographic examination, the sample needs to be carefully handled, to ensure that there is no interference with the metallographic examination results.

Grinding and polishing: The surface of the sample needs to be flattened, bright and clean. Generally, grinding and polishing are used to realize the preparation process of the metallographic sample.

Etching: Etching is to immerse the polished sample into the etching solution, which can differntiate the components of the sample, making more details appear on the surface of the sample.

Observation: After the sample is finished and etched, put it under an optical microscope. At this time, a microscopic image of the sample appears on the screen, which can be observed, analyzed and evaluated.

Auxiliary detection: For different metal materials, sometimes need to do other auxiliary detection methods, such as physical, chemical and instrumental methods, to achieve a comprehensive evaluation of the metal material properties.

Metallographic examination plays an irreplaceable role in the metal engineering process. It is an important means for users to understand the application performance and reliability of metal materials. Therefore, it is necessary to carry out regular and systematic testing and inspection of metal materials, so as to ensure the smooth progress of metal engineering processes.

Metallographic Examination

Metallographic examination is an important analysis method to measure the properties of materials. It provides important information on the microstructure of metals, alloys and other materials, which can then be used to assist in determining various properties.

Metallographic examinations are commonly used to identify microstructural features, such as grain size, presence of inclusions or grain boundaries, presence of precipitates, and amount of plastic deformation. Microstructural features can have a great effect on material properties and play an important role in the selection of materials. In some cases, such as welds, the microstructure can also be used to determine process parameters.

In order to perform a metallographic examination, the material must be prepared. The preparation process involves embedding the sample in a suitable cement, grinding and polishing it, and etching it with an appropriate reagent. The etching also helps to reveal any microstructural features that may not be visible in the bare sample.

Once the sample is prepared, it can be examined using an optical microscope. The optical images are then used to determine the average grain size, the degree of cold work and the presence of defects. In some cases, additional examination techniques such as scanning electron microscopy may be used to further characterize the microstructure.

Metallographic examination can be used to assess the quality of materials and components. It is also a valuable tool for researching the effects of processing and environmental exposure on the microstructure.