JB/T 7999-2001 This standard is a revision of JB/T 7999-1995 "Determination method of bulk density, total porosity and water absorption of abrasive bodies". Some technical contents were modified during the revision. This standard specifies the determination principle, measurement equipment and measurement method of bulk density, total porosity and water absorption of ordinary abrasive bodies. This standard is applicable to the determination of bulk density, total porosity and water absorption of ordinary abrasives. This standard was first issued in March 1989 as GB 11269-89, and the standard number was adjusted to JB/T 7999-95 in April 1996. This is the first revision. JB/T 7999-2001 Test method of bulk density, total porosity and water absorption of abrasive bodies JB/T7999-2001 Standard download decompression password: www.bzxz.net

JB/T7999-2001
This standard is a revision of JB/T7999-1995 "Determination of bulk density, total porosity and water absorption of abrasives" (formerly GB11269-89).
The technical content of this standard is basically consistent with that of JB/T7999--1995. Only some technical contents have been revised. This standard replaces JB/T7999-1995 from the date of implementation. This standard is proposed and managed by the National Technical Committee for Standardization of Abrasives and Grinding Tools. The drafting unit of this standard: Zhengzhou Abrasives and Grinding Research Institute. The main drafters of this standard: Yang Songcan, Liu Min, Tian Songqiao. This standard was first issued in March 1989 as GB11269-89, and the standard number was adjusted to JB/T7999-1995 in April 1996. This is the first revision.
Machinery Industry Standard of the People's Republic of China
Testing methods for the volume density, general porosity and water absorption of bonded abrasive products Scope
JB/T7999—2001
Replaces JB/T7999—1995
This standard specifies the determination principle, equipment and method for the volume density, general porosity and water absorption of ordinary abrasives. This standard is applicable to the determination of the volume density, general porosity and water absorption of ordinary abrasives. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is issued, the versions shown are valid. All standards will be revised, and the parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T16458.2—1996 Terminology of abrasives and grinding tools Part 2: Terminology of abrasive tools JB/T7984.3—2001 Determination of density of common abrasives 3 Definitions
This standard adopts the following definitions.
3.1 Volume density
See the provisions of 3.2 in GB/T16458.2-1996. 3.2 True density
See the provisions of 3.3 in GB/T16458.2--1996. 3.3 Open porosity
See the provisions of 3.4.3 in GB/T16458.2—1996. 3.4 Closed porosity See the provisions of 3.4.4 in GB/T16458.2—1996. 3.5Total porosity
See the provisions of 3.4.5 in GB/T16458.2-1996. 3.6Water absorption
See the provisions of 3.5 in GB/T16458.2-1996. 4Principle
Weigh the mass of the sample, use a vacuum pumping device to remove the air in the open pores of the sample, fill it with liquid, weigh the mass of the sample saturated with liquid in the liquid and in the air respectively, and calculate the various physical quantities. The saturated sample is a sample whose open pores are completely filled with liquid. 5 Equipment
5.1JS1-A vacuum pumping device or other vacuum pumping device, when no sample is placed, the residual pressure is required to be less than 2.67kPa. 5.2Analytical balance: weighing 200g, the graduation value is 0.1mg. Approved by China Machinery Industry Federation on March 29, 2001 488
Implemented on July 1, 2001
5.3 Electric oven: can be controlled at 110°C ± 5°C. 5.4 Dryer.
5.5 Mesh cloth.
JB/T7999—2001
5.6 Beakers: 2, 500ml., one of which has a metal mesh at the bottom. 5.7 Test sieve: sieve number is 10-60. bzxz.net
5.8 Thermometer.
5.9 Immersing liquid: distilled water can be used as the immersion liquid for samples that do not react with water; kerosene can be used as the immersion liquid for samples that can react with water, and the kerosene should be filtered with quick filter paper before use. 5.10 Precision liquid density meter: used to measure the density of kerosene, with a graduation value of 0.001g/cm. 5.11 Brush: Bristle brush (for softer abrasives), copper brush (for harder abrasives). 6 Sample preparation
Sample quantity: no less than 3 pieces per sample. Sample mass: 10-40g.
The sample should not fall off and have no visible cracks. Brush the surface of the sample clean with a brush, mark it, put it in an electric oven at 110℃±5℃ for 2h, then take it out and cool it to room temperature in a desiccator for use.
7 Determination method
7.1 Weigh the mass of the sample to an accuracy of 0.1mg. 7.2 Place the sample in a beaker with a wire mesh and fill it with distilled water (or kerosene) so that the sample is completely immersed in the liquid. Then place it in a vacuum pump and evacuate it until the residual pressure is less than 2.67kPa. Continue to evacuate for more than 40min until there are basically no bubbles discharged from the sample and stop the pump. Take out the beaker containing the sample and let it stand for 1 hour to make its temperature close to room temperature. 7.3 Weigh the mass of the saturated sample completely immersed in the liquid: Pour the degassed distilled water (or kerosene) into the beaker and place it on the left side of the balance. Hang the saturated sample on the balance hook and immerse it completely in the distilled water (or kerosene). Weigh the mass of the sample hanging in the water (or kerosene) to an accuracy of 0.1 mg.
Each weighing should keep the height of the distilled water (or kerosene) unchanged. 7.4 Weigh the mass of the saturated sample in the air: Take out the sample from the distilled water (or kerosene), gently wipe off the excess liquid on the surface of the sample with a silk cloth soaked in distilled water (or kerosene) (be careful not to suck out the liquid in the pores), quickly put it into the weighing bottle and cover the bottle cap. Weigh the mass of the saturated sample in the air to an accuracy of 0.1 mg. For the above determination of samples that can react with water, kerosene is used as the immersion liquid. 7.5 Determination of liquid density: Measure the temperature of distilled water and find out the density of distilled water according to Table 1. Table 1
Temperature of distilled water, ℃
12～18
31～33
Density of distilled water+z/em
JB/T 7999--2001
When kerosene is used as the diffusing liquid, use a Webster balance or a precision liquid density meter to measure the density of kerosene with an accuracy of 0.001 g/cm. 8 Calculation of results
a) Bulk density is calculated according to formula (1):
b) Open porosity is calculated according to formula (2):
Popen:
c) Total porosity is calculated according to formula (3):
d) Closed porosity is calculated according to formula (4):
m2— mi
×100%
mz— mi
P = Ptotal— The water absorption rate is calculated according to formula (5):
mo×100%
wherein: D
volume density of the sample, g/cm\;
open porosity of the sample, %;
total porosity of the sample, %;
closed porosity of the sample, %;
water absorption rate of the sample, %;
mass of the dry sample·g
saturated sample The mass suspended in the liquid, g; The mass of the saturated sample in the air,;
The density of the immersion liquid, g/cm2;
(2)
(3)
(4)
(5)
The true density of the sample, g/cm2. The sample is crushed and ground in a mortar, passed through a sieve with a mesh number of 10~~60, and the iron is absorbed by a magnet. The measurement is carried out according to the provisions of JB/T7984.3. 9 Allowable error
The same sample (not less than 3 pieces) is measured in the same laboratory using the same measurement method. The difference between the average values ​​of the two measurement results shall not exceed the following provisions:
Volume density: 0.05g/cm2;
Porosity: 2%;
Water absorption: 1%.
10 Test report
For the same sample, take the arithmetic mean of the test results and report the results according to the following regulations. The porosity and water absorption rate are accurate to the integer part, and the bulk density is accurate to two decimal places. 490
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