Fasteners, also known as standard components, have a wide variety of types, diverse uses, and varying technical requirements. Therefore, the technical conditions of fasteners do not require all inspection items to be carried out Each fastener technical condition will require specific metallographic inspection items. Fasteners vary in size and shape, including long, round, flat, etc. The sampling and cutting methods for samples vary depending on the inspection requirements. What type of metallographic cutting machine is suitable for this specific requirement? Chaineng Metallography editor will briefly introduce to friends.


To select a suitable metallographic cutting machine for the metallographic sample cutting of fasteners, it is first necessary to clarify the technical characteristics of the fasteners. The technical conditions for fasteners almost always require representative fastener specimens to be cut longitudinally to expose their head contour, threads, and smaller lengths of the body stem, as shown in Figure 1.

    A more effective way to achieve this is to slightly deviate from the center when positioning the cutting edge of the metallographic cutting machine, in order to leave sufficient material loss margin for subsequent polishing and polishing processes. To accurately cut and locate such a small sample, the blade width must be kept narrow enough, and only the precision metallographic cutting function can meet the requirements.


Usually, precision metallographic cutting machines use linear cutting and laser positioning, with an accuracy of up to micrometers. Precision metallographic cutting machines are equipped with dedicated fastener vises, which can firmly clamp and position the samples. Due to the fact that precision metallographic cutting machines are generally automatic, they provide high control over cutting conditions such as precise positioning, loading force, and feed speed for the samples to be cut, thereby enabling better cutting of fastener samples to the right extent. In addition, using thinner cutting pieces designed specifically for this precision metallographic cutting machine can achieve precise and less cutting loss, and the surface quality of the final sample's cut must be better than that of the surface cut by ordinary metallographic cutting machines.

    For example, when we use the MetLab low-speed precision cutting machine METCUT-5 from the United States, its performance is very advantageous. The cut section is very flat and smooth, with almost no deformation or burns, which can eliminate the rough grinding process. After embedding, it can be directly polished with P1000 or above metallographic sandpaper.


Of course, when inlaying, potential unqualified defects usually appear at the edges of the threads. The selected inlay resin should have better edge retention performance, and these parts must not be rounded during preparation, otherwise it will be difficult or impossible to analyze the edges of the sample.


For the cutting of metallographic samples with special technical requirements for fasteners, only precision metallographic cutting machines can cut them perfectly. Have you chosen the right one?