GB/T 5164-1985 Determination of open porosity of permeable sintered metallic materials GB/T5164-1985 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of open porosity of permeable sintered metal materials This standard specifies the method for determining the open porosity of permeable sintered metal materials. UDC 669-492.8
: 620.184
GB 5164—85
This standard is equivalent to the relevant parts of ISO2738 "Permeable sintered metal materials-Determination of density and open porosity". This standard is particularly applicable to sintered metal porous bearings and mechanical parts made of metal powder by molding and sintering. 1 Principle
Open porosity is defined as the percentage of volume occupied by open pores in the sintered sample, which can be calculated from the increase in mass of the sample after immersion.
2 Sample
2.1 Clean the surface of the sample. If the sample contains oil, remove the oil with a Soxhlet extractor. Then place it in a desiccator to dry, keep it for 1 hour and then cool it to room temperature.
2.2 If the sample volume is less than 0.5cm3, several samples can be collected and measured together. If the sample is too large, the sample can be broken into small pieces for testing, and the whole sample (not more than 200g) can be used for testing as much as possible. 3 Instruments and reagents
3.1 The Soxhlet extractor is indicated by the attached figure in GB5165-85 "Determination of oil content of permeable sintered metal materials". 3.2 The analytical balance
must have sufficient capacity to weigh the sample mass accurately to 0.01%. 3.3 The container for distilled water
must be large enough to hold the sample and the weighing device (indicated by the attached figure in GB5165-85). 3.4 The vacuum oil immersion device
can make the sample oil under vacuum. The pressure in the container should be reduced to between 0.1 bar (75 mmHg) and 0.01 bar (7.5 mmlig). bZxz.net
3.5 Dryer oven
The temperature in the container can be maintained at 110±5℃. 3.6 Diffusion oil of known density
If the density of the oil is unknown, it can be determined by the pycnometer method. 3.7 Solvent for oil
The choice of solvent should ensure complete dissolution of the contained oil. Usually light gasoline, ether or carbon tetrachloride is used as the solvent. 4 Test steps
4.1 Weigh the cleaned sample.
4.2 In order to make the sample fully oily, use a vacuum oil immersion device to immerse the sample in oil. Put the sample in a container, then evacuate the vacuum to make the pressure below 0.1 bar, keep it at low pressure for about 20 minutes, and inject 30% hot oil into the container to completely immerse the sample. Keep it at low pressure for another 30 minutes, return to normal pressure, wait for the oil temperature to drop to room temperature, then take out the sample, remove the oil, and wipe off the oil on the surface with absorbent paper or cloth. Be careful to avoid sucking out the oil in the hole, and then weigh it. Suitable oil should be completely immiscible with water and be able to wet porous metal. Note: Usually the kinematic viscosity of oil at 20°C is between 50×10-6m2/s and 300×10-fm2/s (50 to 300 cSt). It is within the range of 1SO VG20 to VG150 specified in 1SO3448. Using low-viscosity oil will cause faster than using high-viscosity oil. The oil-immersed sample is placed in a weighing device or hung with a fine nylon thread, first weighed in air, and then immersed in water. 4.3
In order to remove bubbles attached to the sample, the sample can be gently shaken in water, or 1 to 2 drops of wetting agent can be added to the water. 4.4
The sample and water should be at the same temperature, usually the test temperature is room temperature. 5 Calculation and expression of results
5.1 Calculation of results
The open porosity is expressed as the volume percentage of pores that can make the sample contain oil. n3-m2
where: 一一is the open porosity expressed as a volume percentage, %×100
m2--the mass of the oil-free (dry) sample weighed in air, gm--the mass of the oil-containing (completely impregnated) sample weighed in air, gPz--the density of the impregnated oil, g/cm2, V-the volume of the sample, cm3.
It can be determined by the reduction in the mass of the sample when weighed in water, that is: m4-ms
Formula itl: m4
The total mass of the oil-containing sample weighed in air (including the mass of the fine nylon thread), g; the total mass of the oil-containing sample weighed in water (including the mass of the fine nylon thread), g, the density of water, g/cm2.
Expression of results
The open porosity is calculated to the second decimal place and rounded to the first decimal place. 6
Test report
The test report should include the following points:
a. Number of this national standard,
Detailed description required for identification of the sample:
Results obtained and test method applied,
d. Density of the immersion oil;
All other operations not specified or optional in this national standard; Detailed description of all factors that may affect the results. Additional notes:
This standard was proposed by the Ministry of Metallurgical Industry of the People's Republic of China and China National Nonferrous Metals Industry Corporation. This standard was drafted by the Central Iron and Steel Research Institute of the Ministry of Metallurgical Industry. The main drafter of this standard is Tang Guifen.
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