Metallographic analysis is one of the main methods for studying the internal structure and defects of metals and their alloys, and it plays a very important role in the field of metal material research. The method of using a metallographic microscope to magnify 100-1500 times on specially prepared specimens to study the microstructure of metals and alloys is called metallographic microanalysis. It is a basic experimental technique for studying the microstructure of metal materials. Microscopic analysis can study the relationship between the microstructure and chemical composition of metals and alloys; It can determine the microstructure of various alloy materials after different processing and heat treatment; It can distinguish the quality of metal materials, such as the quantity and distribution of various non-metallic inclusions such as oxides and sulfides in the organization, as well as the size of metal grain size.

There are many types and models of metallographic microscopes, with the most common being desktop, vertical, and horizontal types. Metallographic microscopes typically consist of three major components: optical systems, lighting systems, and mechanical systems. Some microscopes also come with photography devices. Taking the 4X metallographic microscope as an example to illustrate, the physical image of the 4XI metallographic microscope

The optical system of the 4X metallographic microscope focuses the light emitted by bulb 1 through the condenser lens group 2 and reflector 8 to the aperture light bar 9, then through the condenser lens 3 to the rear focal plane of the objective lens, and finally shines parallel to the surface of sample 7 through the objective lens. The light reflected from the sample passes back through the objective lens group 6 and auxiliary lens 5, turns from the semi reflector 4, passes through the auxiliary lens and prism to create an inverted magnified real image of the observed object. This image is then magnified by the eyepiece 15 to form the enlarged image that can be seen in the eyepiece field of view.

1) Firstly, plug the light source plug of the microscope into the transformer and connect the power supply through a low-voltage (6-8V) transformer.

2) Select the desired objective and eyepiece according to the magnification, install them on the objective holder and inside the eyepiece cylinder, and turn the converter to a fixed position.

3) Place the specimen in the center of the specimen table, with the observation surface facing downwards and press it down with a spring.

4) Rotate the coarse adjustment handwheel to first lower the stage and observe with your eyes to make the objective lens as close as possible to the surface of the sample (but not touching). Then, rotate the coarse adjustment handwheel in the opposite direction to gradually raise the stage to adjust the focal length. When the field of view brightness increases, use the fine adjustment handwheel to adjust until the object image becomes clear.

5) Adjust the aperture light barrier and field of view light barrier appropriately to obtain high-quality images.