This standard specifies the method for testing the hardness of abrasive tools with a sandblasting hardness tester. This standard is applicable to common abrasive tools with ceramic and resin bonds and abrasive grain sizes of F36 to F150. GB/T 2490-2003 Method for testing the hardness of common abrasive tools with a sandblasting hardness tester GB/T2490-2003 Standard download decompression password: www.bzxz.net

This standard replaces GB/T2490-1984 "Method for testing abrasive tool hardness by sandblasting hardness machine". Compared with GB/T2490-1984, the main changes of this standard are as follows: the difference value of abrasive tool hardness and the term of uniformity are added; the provisions of the measurement position of abrasive tool sandblasting hardness are added; the requirements of abrasive tool hardness uniformity are added to how to determine the hardness grade; GB/T2490-2003
In the comparison table of determining the hardness grade of abrasive tool by the measured pit depth value of abrasive tool, the difference value h and the uniformity tolerance value are added; the operation requirements are added "If the measured value of a certain point is not within the allowable range, it can be rechecked once near the point". This standard is proposed by China Machinery Industry Federation. This standard is under the jurisdiction of the National Technical Committee for Standardization of Abrasives and Grinding Tools (SAC/TC139). This standard was drafted by Zhengzhou Abrasives and Grinding Research Institute. The main drafters of this standard are: Chen Wenping, Liu Yong, Miao Qing, Zhang Changwu. This standard was first issued in 1981 and revised for the first time in 1984. I
1 Scope
Method for testing hardness of ordinary abrasive tools with sandblasting hardness machine This standard specifies the method for testing hardness of abrasive tools with sandblasting hardness machine. This standard is applicable to ordinary abrasive tools with ceramic bond and resin bond and abrasive grain size of F36~F150. 2 Technical requirements for sandblasting hardness machine and accessories
2.1 Main components of sandblasting hardness machine
2.1.1 The nozzle aperture should be 5.5mm~6.0mm; there should be no obvious steps at the inner wall joint. 2.1.2 The cone bottom aperture of the conical nozzle should be 5.5mm~6.0mm. 2.1.3 The aperture of the interface nozzle should be 4.5mm~5.0mm. 2.1.4 The outer diameter of the measuring rod should be (4.2±0.1)mm. 2.1.5 The distance from the nozzle to the abrasive surface should be (9±1)mm. 2.1.6 The accuracy of the pressure gauge should not be lower than Class 1.5. GB/T2490--2003
2.1.728cm2 sand chamber: the volume of quartz sand should be (28±1)cm2, 5cm2 sand chamber: the volume of quartz sand should be (5±0.5)cm2.2.2 Quartz sand
2.2.1 Chemical composition:
SiO2≥96%;
Loss on ignition≤0.30%;
Impurities≤1%.
2.2.2 Density: (2.64±0.02)g/cm. 2.2.3 Particle size: the residue on the test sieve 0.85/0.5 is not more than 3%; the amount passing the test sieve 0.5/0.315 is not more than 8%. 2.3 Calibration glass
2.3.1 The thickness of sodium flat glass is 5mm. 2.3.2 Each time calibration is performed, no less than 5 points should be measured on the glass, and the depth of the sandblasting pit at each point should meet the following requirements: (2.13±0.05) mm for the 28cm2 sand chamber; (0.53±0.03) mm for the 5cm2 sand chamber. 3 Working conditions of sandblasting hardness machine
3.1 Air pressure in the air chamber: p=0.15MPa. 3.2 Abrasives with hardness grades F to L are measured in a 5cm2 sand chamber. Abrasives with hardness grades M to Y are measured in a 28cm2 sand chamber. 4 Test method for sandblasting hardness of abrasives
See Table 1 for the measurement locations of sandblasting hardness of abrasives.
GB/T 2490--2003
Abrasive tool type
Type 1, Type 3, Type 4, Type 5, Type 23, Type 38 Type 7, Type 8, Type 26
Type 31, Type 54, Type 90
Type 6, Type 11
Type 12a, Type 12b
Table 1 Abrasive tool sandblasting hardness test location
Minimum size of the tested abrasive tool
Thickness: P and harder abrasive tools, Not less than 6mm; for N and softer abrasives, not less than 8mm
Effective area: not less than 30mm×30mm
Various sizes
Effective area: not less than 30mm×30mm
Various sizes
Various sizes
4.2 The measurement operation shall meet the following requirements:
During measurement, the triangular end face of the adjustment sleeve support head shall be completely in contact with the abrasive. 4.2. 1
Measurement location
1/2 from the hole, measure two points symmetrically
1/2 from the groove, measure two points symmetrically
Wide surface along the length direction center line from the edge L/5, measure two points symmetrically
1/2 from the hole, measure two points symmetrically
1/2 of the ring end face, measure two points symmetrically. When the effective area is not enough, measure two points symmetrically in the middle of the outer circle. 1/3 of the height from the upper mouth of the outer cylindrical surface (external cone), measure two points symmetrically
1/2 from the edge of the inner cone, measure two points symmetrically. During operation, glass should be used to calibrate the stability of the sandblasting hardness machine. After the quartz sand is completely ejected from the sand chamber, the machine head should keep pressing the abrasive surface to measure the pit depth value. When measuring the hardness, the abrasive surface should be flat and there should be no rough processing marks. If the measurement value of a certain point is not within the allowable range, it can be checked again near the point. Determination of sandblasting hardness of abrasive tools
According to the measured pit depth value, determine the hardness grade of the abrasive tools in accordance with the provisions of Table 2. 5.1
5.2 The uniformity of the hardness of the abrasive tools shall not be greater than the uniformity tolerance value, otherwise it shall be judged as unqualified. When the uniformity of the hardness of the abrasive tools meets the requirements, the arithmetic mean of each measuring point shall be taken, accurate to two decimal places; if the average value is within the allowable range specified in standard 5.3
, it shall be judged as qualified. Table 2 Comparison table of abrasive tool hardness grade and pit depth measured by sandblasting hardness machine Hardness grade
Hardness value and allowable range
Hardness value
Allowable range
Grade difference
Uniformity allowance
Hardness value
Allowable range
Grade difference
Uniformity allowance
F36~F40
F46F54
F60~F90
Sand chamber 5cm2, air pressure: 0.15MPa
4.20~3.56
4.80~3.26
3.55~2.96
3.88~2. 68
4.84~4.16
5. 24 -~3. 83
4.15~3.50
4.50~3.20
5, 24 ~4. 51
5. 54 ~4. 18 | 66
Hardness grade
Hardness value and allowable range
Hardness value
Allowable range
Differential value
Uniformity tolerance
Hardness value
Allowable range
Differential value
Uniformity tolerance
Hardness value
Allowable range
Differential value
Uniformity tolerance
Hardness value
Allowable range
Differential value
Uniformity tolerance
Hardness value
Allowable range
Differential value|| tt||Uniformity tolerance
Hardness value
Allowable range
Differential value
Uniformity tolerance
Hardness value
Allowable range
Differential value
Uniformity tolerance
Hardness value
Allowable range
Differential value
Uniformity tolerancewww.bzxz.net
F36～F40
2.95~2.41
3.25~2.14
2.40~1.87
2.67~1.61
1.86~1, 36
1.60~0.73
Table 2 (continued)
F46~F54
3.49~~2.90
3.82~2.62
2.89~2.35
3.19~2.07
2.34 ~1.80
2.61~1.57
1.79~1.35
2.06~1.14
Sand chamber: 28cm2, air pressure: 0.15MPa
3.55~2.39
2.92~1.95
2. 14~1.76
1.94~1.35
4.43~3.03
3.66~2.50
2.73~2. 27
2. 49~1.80
F60~F90
3. 84~3. 23
4,17~2.94
3.22~2.66
3.53~2.41
2,65~2.16
2.93~1.93
2.15~1.70||t t||2.40~1.50
4.74~4.01
5.08~3.68
4.00~3.36
4.38~3.10
3.35~2.84||tt| |3. 67~2.64
GB/T 2490—2003
Unit is millimeter
F100～F150
3.95～3.36
4.27~3.08
3.35~2.80
3.65~ 2.55
2.79~2.30
2.29~1.85
5.00~4.56
5.23~4.36
4.55~4.16||tt ||4.78~3.96
4.15~3.76
4.35~3.58
3.75~3.41|| tt||3.95~3.26
GB/T2490—2003
Hardness grade
Hardness value and allowable range
Hardness value
Allowable range||tt ||Grade difference value
Uniformity tolerance
Hardness value
Allowable range
Grade difference value
Uniformity tolerance
Hardness value
Allowable range
Differential value
Uniformity tolerance
Hardness value
Allowable range
Differential value|| tt||Uniformity tolerance
F36～F40
1. 451.24
1.60~1.14
1.23~1.05
:1.34~0.98
1. 04 ~0. 92
1.13~0.86
Table 2 (continued)
F46~F54
2.09-1.54
1.65~1. 43
1.79~1.34
1. 53~1. 20
1.25~1.16
F60~F90
2.43~2.13
2.12~1.88
2. 27~1. 77
1.87~1.67
1.99~1.61
1.66~1.56
The unit is millimeters
F100~F150
3. 40~3.11
3.57~3.00
3.10~~2.90
3.25~2.80
2.89~2.70
2.99~2. 62
2.69~2.55
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