The essential difference between microscope and magnifying glass
Microscope is also an auxiliary tool for eyes. It is mainly used to observe the tiny details of close objects. It is widely used in various scientific and technical fields and is an extremely important visual optical instrument.
Working principle of microscope
Microscope and magnifying glass play the same role, that is, to form an enlarged image of a tiny object at a close distance, and the opening angle of the image to the human eye is much larger than that when the human eye looks at the object directly.
The difference between them is that the magnification of magnifying glass is not high, generally below 15X; The visual magnification of the microscope can reach more than 1000 times.
Magnifier structure is relatively simple, generally just a group of lenses, the essence is a magnification; However, the microscope has a complex structure, generally two sets of lenses, and its essence is secondary magnification.
The principle of secondary magnification of microscope is to first use a lens with a short focal length to make a tiny object into an enlarged real image, that is, to enlarge the object horizontally several times, and then use a magnifying glass to observe the primary image that has been enlarged horizontally.
Several applications of microscope in production
1. Inspection of raw materials by metallographic microscope: inspection of metallurgical quality of raw materials such as segregation, distribution type and grade of nonmetallic inclusions; Check the casting porosity, porosity and slag inclusion uniformity of casting materials; Inspect the surface of forged parts for decarburization, overheating, overburning, cracks and deformation.
2. Quality control in the production process: the metallographic microscope can provide the basis for adjusting the process and modifying the process parameters, and guide the production, such as whether the heating temperature of heat treatment and quenching, the time of heat preservation and the cooling rate are appropriate (correct); Control of process parameters of chemical surface heat treatment; Whether the initial and final forging temperatures of forging are appropriate, etc.
3. Failure analysis of metallographic microscope: metallographic structure analysis method is widely used in mechanical failure analysis, which is convenient for identifying some common defects. Such as decarburization of the surface of parts; Morphology and distribution characteristics of microcracks; Defects of chemical heat treatment; Abnormal structure after heat treatment; Grain boundary brittle phase precipitation, etc. The results of metallographic analysis are often used as the basis of fault analysis.
4. Product quality inspection: Some mechanical parts or products require not only mechanical properties and physical properties, but also microstructure parameters as one of the technical indicators for quality evaluation.
