Careful selection of metallographic abrasive paper and diamond grinding disc should be made for grinding metal and alloy samples.


One of the important methods to study the internal structure of metals and alloys is metallographic examination. The basic work of metallographic examination is to prepare the surface of high-quality metallographic samples without scratch and deformation damage, so as to ensure that the real microstructure of the material can be observed under the metallographic microscope and obtain reliable data and evaluation conclusions. For the preparation of metal and alloy samples, one of the most important processes is grinding. How to select the appropriate metallographic abrasive paper or diamond grinding disc is particularly important. Only by selecting the appropriate grinding consumables, can we obtain good working effect and save the cost of sample preparation. We begin by understanding the difference between metallographic sandpaper and diamond grinding disc in application.

Silicon carbide abrasive medium is generally used for metallographic abrasive paper. Water resistant abrasive paper is very common, and the particle size of abrasive medium is from 260 μ M-5 μ M. Compared with diamond grinding disc, it is more suitable for grinding metal and alloy samples with low hardness. In general, when the hardness of the sample is lower than 150hv, or when the hardness is higher than 150hv but the ductility is better, it is appropriate to use metallographic sandpaper! Because of these characteristics of materials, grinding with silicon carbide metallographic abrasive paper can give play to the grinding ability of abrasive paper for rapid material removal, so as to obtain samples with uniform surface finish that meet the technical requirements, and it is also more economical.


The grinding medium of diamond grinding disc is diamond with particle size from 240 μ M-6 μ m. It is suitable for high hardness materials such as thermal sprayed metal coatings and cemented carbides. Because the hardness of this kind of material is higher than 150hv, grinding with metallographic abrasive paper is like scratching the surface, which is difficult to achieve effective grinding and removal effect. Only diamond can exert its powerful grinding ability, and the grinding efficiency is unmatched by metallographic abrasive paper. At least 100-200 pieces of silicon carbide metallographic abrasive paper can be replaced by a diamond grinding disc, and the process can be saved by using the diamond grinding disc. When the metallographic abrasive paper needs 2-3 grades of metallographic abrasive paper grinding process, if one process of each grade of the diamond grinding disc can be used to meet the grinding requirements. Diamond grinding discs have higher removal rate, wear resistance and long service life. The edge of the sample ground with a diamond grinding disc is well maintained, and the flatness is also quite good.

Through the above understanding and comparison, how to select is very simple. For grinding metal and alloy samples, it is necessary to carefully select metallographic abrasive paper and diamond grinding disc, just remember a little.


Diamond grinding disc grinding: suitable for grinding metallographic samples of materials with hardness above 150hv;


Metallographic sandpaper: it is applicable to the grinding of materials with hardness below 150hv, or material samples with good ductility although hardness is higher than 150hv.


As long as you keep this principle in mind, the choice will not be wrong.


Metallographic consumables such as diamond polishing fluid, polishing coolant polishing cloth, alumina/silicon oxide suspension, etc. are usually used in the preparation of metallographic samples of metal and alloy materials. For the selection and application of various consumables, you can directly contact the pulse testing engineer for help.