In addition to the special precautions when using various hardness testers, there are some common issues that should be noted. The following are listed:
1. The hardness tester itself will produce 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 is calibrated with a standard block before measurement. For the Rockwell hardness test results, the difference is within ±1. A stable value with a difference of ±2 can give a correction value. When the difference is outside the range of ±2, the hardness tester must be repaired or replaced by other hardness test methods.
Rockwell hardness scales have a de facto scope of application and should be selected correctly according to the 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 is poor, and the hardness value is not accurate and should not be used. Other hardness testing methods also stipulate corresponding calibration standards. The standard block used to calibrate the hardness tester cannot be used on both sides because the standard surface and the back surface hardness are not necessarily the same. The standard block is generally valid for one year from the date of calibration.
2. When replacing the indenter or anvil, pay attention to the contact parts to be cleaned. After the replacement, it is tested several times with a steel sample of a certain hardness until the hardness values ​​obtained twice in succession are the same. The purpose is to make the contact part of the indenter or anvil and the testing machine compact, and the contact is good, so as not to affect the accuracy of the test result.
3. After the hardness tester is adjusted, when the hardness is measured, the first test point is not used. The measured value is not accurate due to the fear that the sample is not in good contact with the anvil. After the first point is tested, the hardness tester is in the normal operating mechanism state and then the sample is formally tested, and the measured hardness value is recorded.
4. When the test piece allows, generally select at least three hardness values ​​for different parts, take the average value, and take the average value as the hardness value of the test piece.
5. For the shape of the test piece, the corresponding shape of the block should be used, and it can be tested after being fixed. The round test piece is generally tested in a V-groove.
6. Before loading, check whether the loading handle is placed in the unloading position. When loading, the action should be light and steady. Do not use too much force. The loading handle should be placed in the unloading position after loading, so as to avoid the instrument being in a load state for a long time, plastic deformation occurs, which affects the measurement accuracy.
Vickers, Rockwell hardness
Hardness: It is the ability of the material to resist local plastic deformation. It is now measured by indentation.
Note: The hardness values ​​cannot be directly compared with each other and can only be converted by the hardness comparison table.
First, Brinell hardness (HB)
1. Test indenter: steel ball or carbide ball with diameter D;
2. Scope of application: For metals, it is only suitable for measuring the hardness of annealed, normalized, quenched and tempered steel, cast iron and non-ferrous metals.
3. Advantages: small measurement error and stable data;
4. Disadvantages: The indentation is large and cannot be used for too thin or finished parts.
5, Brinell hardness tester HBE-3000 shape design is beautiful and generous, easy to use, free of calculations and other features to facilitate the use of the majority of users. The Brinell hardness test is the largest test method for indentation in all hardness tests. It can reflect the comprehensive properties of the material and is not affected by microsegregation and uneven composition of the sample structure, so it is a high precision. Hardness test method.
Brinell hardness tester HBE-3000 technical parameters:
Total test force (N): 612.5, 980, 1225
Brinell hardness test (N): 1837.5, 2450, 4900, 7350, 9800, 14700, 29400
Hardness measurement range: 8-650HBW (hard alloy steel ball)
Microscope magnification: 20X
Maximum allowable height of the test piece (mm): 220
Indenter center to body distance (mm): 135
Brinell hardness tester power supply voltage: AC220V/50HZ
Second, Rockwell hardness (HR)
1. Classification and application range of Rockwell hardness: Rockwell hardness can be divided into: HRA, HRB, HRC according to the material of the indenter and the load applied by the indenter. HRA is suitable for measuring cemented carbide, surface hardened layer or carburized layer; HRB is suitable for measuring non-ferrous metals and annealing, normalized steel, etc.; HRC is suitable for quenched and tempered steel, hardened steel, etc.
2. The advantages of Rockwell hardness: simple operation, small indentation and wide application range;
3. The disadvantage of Rockwell hardness: the measurement results have a large dispersion.
4, Rockwell hardness tester R (D)-150A1 is a manual loading and unloading test force Rockwell hardness tester, for the determination of Rockwell hardness of ferrous and non-ferrous metals. Widely used in the factory floor and metrology departments.
Rockwell hardness tester R (D)-150A1 technical parameters:
Initial test force (N): 98
Total test force (N): 588,980,1471
Hardness reading method: table
Maximum allowable height of the test piece (mm): 170
Indenter center to body distance (mm): 140
Hardness test range:
(20-88) HRA
(20-100) HRB
(20-70)HRC
Third, Vickers hardness (HV)
1. Test indenter: diamond square pyramid, the load is small;
2. Advantages of Vickers hardness: The advantages of Brinell hardness and Rockwell hardness are retained, and the hardness of materials ranging from extremely soft to extremely hard can be measured and compared with each other.
3. The Vickers hardness tester HVC-5A1 is a manual type Vickers hardness tester, and the HVC-5D1 type is an automatic turret hardness tester. This machine uses a high-magnification optical measuring system, and the eyepiece drum reads once. Depth and hardness gradients for steel, non-ferrous metals, IC flakes, thin plastics, foils, coatings, surface coatings, laminated metals, heat treated carbonized layers and quench hardened layers.
The Vickers hardness tester HVC-5A1 has a built-in hardness calculator that displays the hardness value directly on the LCD screen by inputting the diagonal length of the indentation.
Vickers hardness tester HVC-5A1 technical parameters:
Micro hardness scale: HV0.2, HV0.5, HV1.0, HV2.0, HV3.0, HV5.0
Display: hold time, hardness value, test force
Test force (kgf): 0.2 - 0.5 - 1.0 - 2.0 - 3.0 - 5.0
Load Control: Auto (Load / Hold / Uninstall)
Test force retention time (s): 1 to 99
Test force selection: external selection force knob, test force is displayed on the LCD screen
Objective lens: 10×, 20×
Eyepiece magnification: 10×
Total magnification (μm): 100 ×, 200 ×
Measuring range (μm): 400
Resolution (μm): 0.5
Measuring range: (5-3000) HV
XY test bench size (mm): 100 × 100
Stroke range (mm): 25 × 25
Minimum reading (mm): 0.01
Maximum height of test piece (mm): 85
Maximum width of the test piece (mm): 120 (from the center line of the indenter to the wall distance)
Output: Built-in micro-play (optional), RS232 serial interface
Vickers hardness tester power supply voltage: AC220V/50HZ
1. The hardness tester itself will produce 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 is calibrated with a standard block before measurement. For the Rockwell hardness test results, the difference is within ±1. A stable value with a difference of ±2 can give a correction value. When the difference is outside the range of ±2, the hardness tester must be repaired or replaced by other hardness test methods.
Rockwell hardness scales have a de facto scope of application and should be selected correctly according to the 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 is poor, and the hardness value is not accurate and should not be used. Other hardness testing methods also stipulate corresponding calibration standards. The standard block used to calibrate the hardness tester cannot be used on both sides because the standard surface and the back surface hardness are not necessarily the same. The standard block is generally valid for one year from the date of calibration.
2. When replacing the indenter or anvil, pay attention to the contact parts to be cleaned. After the replacement, it is tested several times with a steel sample of a certain hardness until the hardness values ​​obtained twice in succession are the same. The purpose is to make the contact part of the indenter or anvil and the testing machine compact, and the contact is good, so as not to affect the accuracy of the test result.
3. After the hardness tester is adjusted, when the hardness is measured, the first test point is not used. The measured value is not accurate due to the fear that the sample is not in good contact with the anvil. After the first point is tested, the hardness tester is in the normal operating mechanism state and then the sample is formally tested, and the measured hardness value is recorded.
4. When the test piece allows, generally select at least three hardness values ​​for different parts, take the average value, and take the average value as the hardness value of the test piece.
5. For the shape of the test piece, the corresponding shape of the block should be used, and it can be tested after being fixed. The round test piece is generally tested in a V-groove.
6. Before loading, check whether the loading handle is placed in the unloading position. When loading, the action should be light and steady. Do not use too much force. The loading handle should be placed in the unloading position after loading, so as to avoid the instrument being in a load state for a long time, plastic deformation occurs, which affects the measurement accuracy.
Vickers, Rockwell hardness
Hardness: It is the ability of the material to resist local plastic deformation. It is now measured by indentation.
Note: The hardness values ​​cannot be directly compared with each other and can only be converted by the hardness comparison table.
First, Brinell hardness (HB)
1. Test indenter: steel ball or carbide ball with diameter D;
2. Scope of application: For metals, it is only suitable for measuring the hardness of annealed, normalized, quenched and tempered steel, cast iron and non-ferrous metals.
3. Advantages: small measurement error and stable data;
4. Disadvantages: The indentation is large and cannot be used for too thin or finished parts.
5, Brinell hardness tester HBE-3000 shape design is beautiful and generous, easy to use, free of calculations and other features to facilitate the use of the majority of users. The Brinell hardness test is the largest test method for indentation in all hardness tests. It can reflect the comprehensive properties of the material and is not affected by microsegregation and uneven composition of the sample structure, so it is a high precision. Hardness test method.
Brinell hardness tester HBE-3000 technical parameters:
Total test force (N): 612.5, 980, 1225
Brinell hardness test (N): 1837.5, 2450, 4900, 7350, 9800, 14700, 29400
Hardness measurement range: 8-650HBW (hard alloy steel ball)
Microscope magnification: 20X
Maximum allowable height of the test piece (mm): 220
Indenter center to body distance (mm): 135
Brinell hardness tester power supply voltage: AC220V/50HZ
Second, Rockwell hardness (HR)
1. Classification and application range of Rockwell hardness: Rockwell hardness can be divided into: HRA, HRB, HRC according to the material of the indenter and the load applied by the indenter. HRA is suitable for measuring cemented carbide, surface hardened layer or carburized layer; HRB is suitable for measuring non-ferrous metals and annealing, normalized steel, etc.; HRC is suitable for quenched and tempered steel, hardened steel, etc.
2. The advantages of Rockwell hardness: simple operation, small indentation and wide application range;
3. The disadvantage of Rockwell hardness: the measurement results have a large dispersion.
4, Rockwell hardness tester R (D)-150A1 is a manual loading and unloading test force Rockwell hardness tester, for the determination of Rockwell hardness of ferrous and non-ferrous metals. Widely used in the factory floor and metrology departments.
Rockwell hardness tester R (D)-150A1 technical parameters:
Initial test force (N): 98
Total test force (N): 588,980,1471
Hardness reading method: table
Maximum allowable height of the test piece (mm): 170
Indenter center to body distance (mm): 140
Hardness test range:
(20-88) HRA
(20-100) HRB
(20-70)HRC
Third, Vickers hardness (HV)
1. Test indenter: diamond square pyramid, the load is small;
2. Advantages of Vickers hardness: The advantages of Brinell hardness and Rockwell hardness are retained, and the hardness of materials ranging from extremely soft to extremely hard can be measured and compared with each other.
3. The Vickers hardness tester HVC-5A1 is a manual type Vickers hardness tester, and the HVC-5D1 type is an automatic turret hardness tester. This machine uses a high-magnification optical measuring system, and the eyepiece drum reads once. Depth and hardness gradients for steel, non-ferrous metals, IC flakes, thin plastics, foils, coatings, surface coatings, laminated metals, heat treated carbonized layers and quench hardened layers.
The Vickers hardness tester HVC-5A1 has a built-in hardness calculator that displays the hardness value directly on the LCD screen by inputting the diagonal length of the indentation.
Vickers hardness tester HVC-5A1 technical parameters:
Micro hardness scale: HV0.2, HV0.5, HV1.0, HV2.0, HV3.0, HV5.0
Display: hold time, hardness value, test force
Test force (kgf): 0.2 - 0.5 - 1.0 - 2.0 - 3.0 - 5.0
Load Control: Auto (Load / Hold / Uninstall)
Test force retention time (s): 1 to 99
Test force selection: external selection force knob, test force is displayed on the LCD screen
Objective lens: 10×, 20×
Eyepiece magnification: 10×
Total magnification (μm): 100 ×, 200 ×
Measuring range (μm): 400
Resolution (μm): 0.5
Measuring range: (5-3000) HV
XY test bench size (mm): 100 × 100
Stroke range (mm): 25 × 25
Minimum reading (mm): 0.01
Maximum height of test piece (mm): 85
Maximum width of the test piece (mm): 120 (from the center line of the indenter to the wall distance)
Output: Built-in micro-play (optional), RS232 serial interface
Vickers hardness tester power supply voltage: AC220V/50HZ
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