Method for measuring brinell hardness

Abstract

The invention relates to a measurement method for Brinell hardness, comprising the following steps: firstly, applying load to the tested sample with a hardness tester to form circular impression on the tested sample; secondly, photographing the impression and inputting the photographed picture to a computer; thirdly, selecting three characteristic points along the boundary points of the impression picture to form a circle; and finally, computing the hardness according to the diameter of the circle generated by the computer and the input load value. With the technical proposal, the invention has convenient operation, precise and fast measurement, and low cost, can reduce the labor intensity, and does not occupy hours of the hardness tester.

Description

technical field [0001] The invention relates to a method for measuring hardness of materials, in particular to a method for measuring Brinell hardness. Background technique [0002] The basic principle of Brinell hardness: apply a certain pressure to the spherical indenter and press it into the surface of the object to be tested. After the load is removed, the object to be tested will leave a circular indentation. The larger the indentation, the softer the material. Smaller indentations indicate harder material. The hardness value is calculated according to the formula according to the diameter of the indenter, the load and the diameter of the indentation. Compared with other methods, Brinell hardness can better reflect the average performance of a larger area of ​​the material, so it is one of the most widely used methods at present. However, the disadvantage of the Brinell hardness test is also obvious, that is, it is very difficult to measure the diameter of the indenta...

AI Technical Summary

Problems solved by technology

However, the disadvantage of the Brinell hardness test is also obvious, that is, it is very difficult to measure the diameter of the indentation.

The current method is to use a reading microscope for measurement, which has the following problems: 1. There is relative movement between the reading microscope and the sample, and the accuracy is limited; 2. The reading microscope is a monocular microscope, and testers have to open one eye and close one eye when working. One eye is very tired; 3. Since the reading microscope has to be in contact with the sample, when the sample is small, the microscope is difficult to stabilize, resulting in difficulty in measurement; 4. After reading, it is necessary to manually calculate and look up the table to get the result, which is very efficient. Low

[0003] Many companies at home and abroad are trying to find a better method to measure the indentation diameter, which can be basically divided into the following two methods: 1. Set up a digital reading microscope on the hardness tester to make the measurement very convenient, but the The test takes up too much time on the hardness tester, which affects the efficiency, and it is still a single-eye measurement, and it cannot be applied to a large number of old-fashioned testers

2. Using the depth to measure the reverse push indentation diameter, in essence, uses the principle of Rockwell hardness. Although it can be read directly, it completely abandons the essence of Brinell hardness and has not yet fully passed the specific technical details, so not accepted by the industry

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