What is a Hardness Tester?

A hardness tester is a hardness tester. Metal hardness measurement was first proposed by Leo Muir, which indicates the material's ability to resist the pressing of hard objects into its surface. It is one of the important performance indicators of metal materials. Generally, the higher the hardness, the better the abrasion resistance.

Hardness Tester

A hardness tester is a hardness tester. Metal hardness measurement was first proposed by Leo Muir, which indicates the material's ability to resist the pressing of hard objects into its surface. It is one of the important performance indicators of metal materials. Generally, the higher the hardness, the better the abrasion resistance.

Chinese name

Hardness Tester

Foreign name

Hardness tester

begins at

1820s

Application

Hardness test is the simplest and most convenient test method in mechanical performance test. In order to replace some mechanical property tests with hardness tests, a more accurate conversion relationship between hardness and strength is required in production.

1. Leeb hardness (Dietmar Leeb)

It can be divided into:

Steel and cast steel, alloy tool steel, stainless steel, gray cast iron, nodular cast iron, cast aluminum alloy, copper-zinc alloy (brass), copper-tin alloy (bronze), pure copper, forged steel, heat treatment, carbonization, hardened hardening layer, Surface coating, steel, non-ferrous metals and small and thin parts, rubber, plastic, IC foil, jewelry, etc.

In addition to the special precautions when using various hardness testers, there are some common issues that should be paid attention to, which are listed below:

1. The hardness tester itself generates two kinds of errors: one is the error caused by the deformation and movement of its parts; the other is the error caused by the hardness parameter exceeding the specified standard. For the second error, the hardness tester needs to be calibrated with a standard block before measurement. For the results of Rockwell hardness test, the difference is within ± 1. A stable value with a difference within ± 2 can give a corrected value. When the difference is outside the range of ± 2, the hardness tester must be calibrated and repaired or measured by another hardness test method.

Each scale of Rockwell hardness has a de facto scope of application, which must be correctly selected according to regulations. For example, when the hardness is higher than HRB100, the HRC scale should be used for testing; when the hardness is lower than HRC20, the HRB scale should be used for testing. Because it exceeds the specified test range, the accuracy and sensitivity of the hardness tester are poor, and the hardness value is not accurate, so it is not suitable to use. Other hardness test methods also provide corresponding calibration standards. The standard block used for calibrating the hardness tester cannot be used on both sides, because the hardness of the standard surface and the back surface may not be the same. Generally, the standard block is valid for one year from the date of calibration.

2. When replacing the indenter or anvil, pay attention to wipe the contact parts clean. After the replacement, the steel sample with a certain hardness shall be tested several times until the hardness value obtained twice is the same. The purpose is to make the contact part of the indenter or anvil tight with the testing machine and make good contact so as not to affect the accuracy of the test results.

3. After the hardness tester is adjusted, when the hardness measurement is started, the first test point is not used. Because the sample is not in good contact with the anvil, the measured value is not accurate. After the first point test is completed, the hardness tester is in the normal operating mechanism state, and then the sample is officially tested, and the measured hardness value is recorded.

4. When the test piece allows, generally choose at least three hardness values from different parts, take the average value, and take the average value as the hardness value of the test piece.

5. For test pieces with complex shapes, corresponding shape pads should be used, and the test can only be performed after fixing. The round test piece is generally tested in a V-shaped groove.

6. Before loading, check whether the loading handle is in the unloading position. When loading, move lightly and stably, and do not use too much force. After loading, the loading handle should be placed in the unloading position to prevent the instrument from being under load for a long time and plastic deformation will occur, which will affect the measurement accuracy.

Vickers and Rockwell hardness

Hardness: It is the material's ability to resist local plastic deformation, which is usually measured by the indentation method.

Note: The hardness values cannot be directly compared with each other, and can only be converted through the hardness comparison table.

Brinell hardness

1. Test indenter: steel ball with diameter D or

1. Brinell hardness tester: It is mainly used to measure unhardened steel, cast iron, non-ferrous metals and soft bearing alloy materials, which is expressed by HBW.

2. Vickers hardness tester: It is mainly used to measure the hardness of ferrous metals, non-ferrous metals, hard alloys (such as aluminum alloys) and the surface carburizing and nitriding layers. It is expressed by HV.

3. Rockwell hardness tester: used for testing the hardness of various steels (including alloy steel and stainless steel). This is the most important and commonly used type of hardness tester. There are the following Rockwell hardness testers, electric Rockwell hardness testers, digital display Rockwell hardness testers, digital display surface Rockwell hardness, digital display Rockwell, surface Rockwell hardness testers.

4. The Brockwell hardness tester can be used for Brinell, Vickers and Rockwell hardness testers. More suitable for development and research.

5, Shore hardness tester Shore hardness tester is used to measure the hardness of rubber, foam, plastics and other materials, mainly HA and HD, the former is a softer rubber hardness parameter, the latter is a harder rubber or Plastic hardness parameters.

7. Pencil hardness tester: This is used to test the hardness of the coating. In order to clamp a pencil on the "car" and let it slide on the coating, judge the coating based on the hardness of the pencil and the scratches on the coating. The hardness of the layer.

8. Leeb hardness tester: This is a smaller hardness tester that can convert various hardness values. It is mainly used for testing of metal materials, especially for larger workpieces.

The development of Chinese hardness testers is not long, but the achievements have not been small. China's hardness tester production is mainly concentrated in: Beijing, Shandong, and Shanghai. Among them, Beijing and Shandong are mainly based on Luo style, and Shanghai is known for Vickers. In terms of export, Chinese hardness testers are sold overseas with preferential prices and high stability. As a fast hardness test method, the Leeb hardness tester has made rapid progress in recent years. The measurement accuracy and accuracy of domestic Leeb hardness measuring instruments have been comparable to the international advanced technology. In 2011, the Leeb hardness tester achieved a number of technological breakthroughs and performance optimizations:

1.Built-in Bluetooth module, support wireless printing

2. The LCD screen display has backlight, and the contrast is adjustable, which is suitable for reading under various operating scenarios.

3. The automatic shutdown time is adjustable, enabling a more optimized power saving mode

4. System transformation with self-learning

5, USB charging, while charging.

6, clear undervoltage, charging instructions.

7: Using imported thermal printer head, smooth printing and clear fonts.

The development of domestic technology is not inferior to the international level, and the export products have been greatly improved. Each manufacturer also has its own characteristics. The homogeneity phenomenon in the past has decreased, and the entire industry ecology has shown a good trend