As we all know, metallographic examination is one of the important methods to study the internal structure of metal and alloy materials. In order to observe the real microstructure of the material under the metallographic microscope, it is necessary to prepare high-quality metallographic sample surface without scratch and deformation damage, which is called metallographic sample preparation. Its main preparation process is: cutting→ Inlay→ Grinding→ Polishing→ Corrosion→ Microscopic observation. Metallographic cutting pieces, hot inlaid resin powder, metallographic sandpaper, diamond grinding disc, metallographic polishing fluid, metallographic polishing cloth and other metallographic consumables will be used in each process. The following is a brief introduction to you.

Cutting: cutting and sampling is the first step of sample preparation. If the sample is very small and precise, resin bonded diamond metallographic cutting piece or cubic boron nitride metallographic cutting piece is selected, and it is more appropriate to use precision cutting machine for metallographic cutting and sampling; If the size of the sample is relatively large and the width of the knife edge is not strictly required, it is more appropriate to use the grinding wheel metallographic cutting blade and the grinding wheel cutting machine for cutting and sampling, and the efficiency is also relatively high.

Inlay: sample inlay is the second step. According to the hardness of the material itself, appropriate hot inlay resin powder is selected, including phenolic resin for low hardness, epoxy resin for high hardness, and transparent resin for visible samples. Automatic hot pressing inlay machine is used to inlay the samples. It should be noted that generally, the curing temperature of imported hot inlay powder is above 300 ℃, and the maximum heating temperature of some inlay machines can not reach this temperature, so attention should be paid to the selection.

Grinding: sample grinding is the third step, and silicon carbide metallographic abrasive paper is the most used, followed by diamond grinding disc. Generally, for alloys with high hardness, diamond grinding disc is more suitable, which not only has high efficiency, but also has better grinding effect than metallographic abrasive paper. Generally, the grinding will start from 320 × sandpaper or grinding disc, from coarse to fine, until the surface of the sample is ground flat.

Polishing: polishing is the fourth step. Suitable diamond polishing fluid is selected for rough polishing and medium polishing. The particle size of the polishing fluid is from 15 μ M-0.1 μ m. According to the sample preparation process requirements of different materials, the appropriate diamond polishing fluid is selected. For final fine polishing, alumina or silica suspension with particle size from 1 μ M-0.02 μ m. According to the characteristics of the material itself and the preparation scheme, the final polishing solution with appropriate particle size is selected for the final polishing of the sample.

Of course, in the polishing process, it is more critical to select the appropriate metallographic polishing cloth to match the polishing liquid. The polishing cloth has nylon, non-woven fabric, man-made fiber, natural silk and other materials, and various weaving forms such as cashmere, cashmere free, perforated, etc., to meet various technical requirements.

Polishing can be carried out on either manual metallographic polishing machine or automatic polishing machine. There is no difference in the selection of metallographic polishing consumables, but the size of consumables should match the size of the grinding plate of the machine.


The above are the metallographic consumables that must be used for metallographic sample preparation of metal and alloy materials. For how to use various consumables and the specific sample preparation scheme, it needs to be determined according to the technical requirements of the specific sample. For details or personalized sample preparation methods, you can directly contact the pulse detection Engineer for help.