This standard applies to the sampling and subsampling of powders for powder metallurgy. GB/T 5314-1985 Sampling method for powder metallurgy GB/T5314-1985 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Sampling Method of Powders for Powder Metallurgical Purposes
Powders for Powder Metallurgical Purposes --Sampling
This standard applies to the sampling and subsampling of powders for powder metallurgical purposes. UDC 621.762:669
-492.2 :620
GB 5314-85
This standard is equivalent to the international standard ISO3954-1977 "Powders for Powder Metallurgical Purposes -- Sampling Method". 1 Terminology
Batch (lot): a certain amount of powder produced or processed under the same conditions. Increment: powder taken out of a batch of powder at one time by a sampling device. Gross sample (grosssample): powder composed of all the incremental samples taken out of a batch of powder. Composite sample (compositesample): the entire total sample after mixing, or a representative part of it. Mixed samples can also be obtained by dividing a batch of powder that has been thoroughly mixed. Test sample: Powder taken from a mixed sample in order to determine a certain property or prepare a test piece. Usually obtained by dividing a mixed sample.
Weighing sample (testportion): A certain amount of powder taken from the test sample (or, if the two are the same, from the mixed sample) for testing.
Test piece (testpiece): An object of a specified shape made from the test sample. Issued by the National Bureau of Standards on August 24, 1985
Implemented on July 1, 1986
Mixed sample
Weighed sample
2 Number of incremental samples
2.1 Sampling from powder in container
GB 5314~~85
Figure 1 Sampling diagram
Unless otherwise agreed, when sampling from powder in container, the number of containers shown in the following table should be randomly selected from the batch of powder. One or more incremental samples are taken from each selected container to form the total sample. If the batch of powder contains containers with different amounts of powder, the selected containers should be representative of the batch of powder, and the number of incremental samples taken from each selected container should be proportional to the amount of powder in the container.
Number of powder containers for batch powder, pieces
21～35
100~149
150199
200～299
Number of containers from which incremental samples should be taken, pieces
GB 5314-85
For every additional 100 or less packaging containers thereafter, additional sampling containers should be added. 2.2 Sampling during continuous flow discharge
If the entire batch of powder is discharged continuously through an orifice, sampling can be performed during the discharge. In this case, incremental samples should be taken at regular intervals throughout the discharge time. The number of incremental samples to be taken depends on the required accuracy. At least 15 incremental samples should be taken, one shortly after the start of discharge, one in the middle of the discharge process, and one shortly before the end of discharge. 3 Sampling
3.1 General rule
The sample portions should be taken so that the resulting mixed sample represents the batch of powder as accurately as possible. NOTE: When a batch of powder is in motion, for example during loading, discharging, transportation and storage, the container is subject to vibration, and uneven mixing may occur at any time.
All surfaces of the sampler that come into contact with the powder should be smooth and clean. 3.2 Sampling process
The properties of the powder should not be changed during the sampling process. 3.2.1 Sub-sampling
Sub-sampling of the whole batch of powder can be carried out using the apparatus and methods described in Chapter 4. 3.2.2 Sampling during continuous flow wwW.bzxz.Net
The dimensions of the sampling container should be sufficiently larger than the cross-sectional area of ​​the powder flow at right angles to the powder flow. When the sampling container is introduced into and withdrawn from the powder flow, each part of the powder flow should have the same opportunity to flow into the container. The simplest method is to allow a sampling container with a rectangular cross-section to pass through the powder flow at a constant speed. 3.2.3 Sampling with a sampler
Different types of samplers can be used. The length of the sampler should allow the powder to be taken out from all depths of the container. The structure of the sampler depends on the fluidity of the powder to be taken. Figures 2 and 3 show two examples of samplers suitable for different fluidities. Figure 2 is suitable for loose powders with good fluidity. It has an inner tube and an outer tube, the bottom is closed, and a longitudinally oblique long hole is provided at an appropriate position of the outer tube. The inner tube has a longitudinally straight long hole with the same width as the outer tube, so that the inner and outer tubes can be opened and closed in turn when rotating. In order to avoid being stuck by large particles during rotation, there should be an appropriate gap between the tubes. When sampling with this sampler, close the long hole first and then slowly insert it to the bottom of the container. It is recommended that the sampler should be inserted in the vertical direction of the storage state of the powder during transportation and storage. When the sampler reaches the bottom, open the long hole so that the powder fills the sampler from bottom to top. Then close the long hole and pull out the sampler. All the powder in the sampler should be poured into the total sample container. 38
Figure 2 Sampler
GB5314-85
Figure 3 Sampler
The sampler shown in Figure 3 consists of an open single-layer tube. The sampler is suitable for powders that can be retained in the tube when it is pulled out of the powder. This can be achieved by selecting an appropriate tube diameter. The sampler should be slowly inserted into the container until it reaches the bottom. It is recommended that the sampler be inserted in the vertical direction of the storage state during transportation and storage of the powder. After reaching the bottom, the sampler is pulled out and the powder taken out is poured into the total sample container. Note: () If the depth of the powder is greater than the height of the elongated hole of the sampler, more than one additional sample should be taken to ensure that the sample is taken at -depth! The number of additional samples is a multiple of the ratio of the powder depth to the elongated hole height. ② If the powder is unevenly mixed in the direction of the sampler insertion and the amount taken out from each layer is unequal, errors will occur. ③ In order to reduce the influence of mixing in the direction perpendicular to the insertion of the sampler, the distribution of the sampler insertion point should be as representative as possible. If several portions are taken from a circular container, the number of portions taken at each equal distance from the axis of the container should be proportional to the distance. If only one portion is taken from the powder in a cylindrical container, the sampler should be inserted at a position 0.7 diameters from the center. 4 Sampling
The size of the sampling device should be adapted to the amount of powder to be divided so that the loss during the sampling process can be ignored and the contamination can be minimized. 339
The following sample dividers are recommended (see Figures 4 to 8). 8. Quarter-division sample divider,
b. Sample divider,
c. Rotary sample divider,
d. Rotary cone sample divider,
eighth-division rotary sample divider.
GB 5314—85
Figure 4 Quarter-division sample divider
Figure 5 Sample divider
Figure 6 Rotary sample divider
GB 5314—85
15~50rpm
Control panel
Figure 8 Eight-division rotary sample divider
Figure 7 Rotary cone sample divider
Additional instructions:
GB5314—85
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 Iron and Steel Research Institute of the Ministry of Metallurgical Industry. The main drafters of this standard are Tong Ruiquan and Zhang Wenyi. 42
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