GB/T 17617-2018 PDF English
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Rule of sampling and inspection for refractory raw materials
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| GB/T 17617-1998 | English | 479 |
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Refractory products. Sampling of raw materials and unshaped products
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GB/T 17617-2018: PDF in English (GBT 17617-2018) GB/T 17617-2018
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 81.080
Q 40
Replacing GB/T 17617-1998
Rule of sampling and inspection for refractory raw materials
(ISO 8656-1:1998, Refractory products - Sampling of raw materials and unshaped
products - Part 1: Sampling scheme, MOD)
ISSUED ON: FEBRUARY 06, 2018
IMPLEMENTED ON: JANUARY 01, 2019
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of PRC;
National Standardization Administration.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 General ... 8
5 Sampling inspection of bulk refractory raw materials ... 9
5.1 Sampling inspection procedure ... 9
5.2 Group-batching ... 10
5.3 Determination of the increment size (mI) ... 11
5.4 Determination of the number of increments (nI) ... 11
5.5 Sampling of increment ... 13
5.6 Synthesis of gross samples and reduction of laboratory samples ... 14
5.7 Laboratory sampling ... 15
5.8 Preparation and testing of test samples ... 15
5.9 Product quality assessment ... 15
6 Sampling inspection of packaged particle size graded materials ... 17
6.1 Sampling inspection procedure ... 17
6.2 Group-batching ... 17
6.3 Extraction of unit packages ... 19
6.4 Taking of unit package samples ... 19
6.5 Laboratory sampling, test sample preparation, testing ... 20
6.6 Product quality assessment ... 20
7 Sampling inspection report ... 22
Appendix A (Informative) Correspondence of chapter and clause numbers between this
standard and ISO 8656-1:1988 ... 24
Appendix B (Informative) Technical differences between this standard and ISO 8656-
1:1988 ... 25
Appendix C (Normative) Calculation of standard deviation and precision of sampling
inspection ... 26
Appendix D (Normative) Empirical estimation of coefficient of variation of quality
characteristics of refractory raw materials ... 36
Appendix E (Normative) Reduction method of refractory raw material sample ... 37
Rule of sampling and inspection for refractory raw materials
1 Scope
This standard specifies the terms and definitions, general principles, sampling
inspection of bulk refractory raw materials, sampling inspection of packaged particle
size graded materials, sampling inspection reports, etc. for sampling inspection of
refractory raw materials.
This standard applies to sampling inspection of refractory raw materials.
2 Normative references
The following documents are essential to the application of this document. For the dated
documents, only the versions with the dates indicated are applicable to this document;
for the undated documents, only the latest version (including all the amendments) is
applicable to this standard.
GB/T 6005 Test sieves - Metal wire cloth, perforated metal plate and electroformed
sheet - Nominal sizes of openings
GB/T 8170 Rules of rounding off for numerical values and expression and
judgement of limiting values
GB/T 18930 Terminology for refractories
GB/T 22555 Acceptance sampling plans and procedures for the inspection of bulk
materials
3 Terms and definitions
The terms and definitions, as defined in GB/T 18930, as well as the following terms
and definitions, apply to this document.
3.1
Refractory raw materials
Bulk refractory materials with the appearance of blocks, granules, powders or
mixtures thereof, used to prepare shaped or amorphous refractory products.
3.2
f) The packaging of samples and the transportation and delivery method to the
inspection laboratory;
g) Laboratory sampling requirements, quality characteristic test methods, the
number of test samples;
h) Rules for evaluating the quality of the inspection batch products based on the
sample test results.
4.2 If the purpose of sampling inspection is to accept the quality of the product, the
sampling inspection scheme shall also clearly specify the quality characteristics items
to be inspected for acceptance. It shall be noted that not all quality characteristics
specified in product quality standards or technical requirements shall be used as
acceptance inspection items. Generally, chemical composition and no more than three
relatively independent main physical characteristics shall be selected as acceptance
inspection items.
4.3 During sampling, sample preparation, sample transfer and storage, care shall be
taken not to change the test performance of the original state of the material, and to
prevent any change in the properties to be tested. For example, when collecting samples
for moisture detection, the sampler shall be made of non-hygroscopic materials,
meanwhile the sample shall be sealed immediately after collection.
5 Sampling inspection of bulk refractory raw materials
5.1 Sampling inspection procedure
For bulk refractory raw materials that have not been graded, sampling inspection shall
be carried out according to the procedure shown in Figure 1. The specific steps are as
follows:
a) Divide into batches;
b) Determine the quantity of each increment;
c) Determine the number of samples to be taken from the inspection batch;
d) Take increment;
e) Synthesize a gross sample;
f) Divide the gross sample into two laboratory samples;
g) Use one of the laboratory samples for testing;
h) Evaluate the quality of the product based on the test results of the first laboratory
of the batch product μ for estimation. σI can be calculated according to the method given
in Appendix C.
5.4.3 If there are not enough previous test data of the same product to be inspected,
meanwhile the exact value of the coefficient of variation CV of the quality characteristic
cannot be obtained, the product non-uniformity category can also be estimated
according to the empirical method in Appendix D, under the agreement of the sampling
personnel of the relevant parties.
5.4.4 There are often more than one quality characteristic to be inspected for a batch of
products; their coefficients of variation CV are usually different. In this case, the value
of the minimum number of samples nI shall be determined, based on the largest
coefficient of variation CV among the quality characteristics to be inspected.
For bulk refractory raw materials, nI shall usually be determined based on the largest
coefficient of variation among the main chemical composition, bulk density, water
absorption.
5.5 Sampling of increment
5.5.1 Before sampling, the inspection batch of products shall be divided into several
parts equal to the number of increments nI, according to the actual sampling conditions;
the volume or weight of the material in each part shall be roughly equal. If sampling is
done during the dynamic process of product loading and unloading, the sampling
intervals can be divided by time; if sampling is done during the static state of product
stacking, the sampling intervals can be divided by regional location.
5.5.2 Dynamic sampling shall be preferred for increment sampling. When sampling in
a dynamic manner, within the first sampling interval, the time point for increment
sampling shall be random, but it cannot start at the starting point. Subsequent increment
sampling shall be done at equal intervals, until the sampling of the entire batch of
products is completed.
5.5.3 When sampling in a static manner, the sampling points for each regional increment
sampling shall not be the same in spatial position. Whether it is a single wagon, truck
or container, the sampling points shall be distributed in a hierarchical, interlaced or
square array arrangement. If the particle size of the material is particularly dispersed,
the increment sampling points shall be staggered at 1/3 or 2/3 of the depth of the pile
or at the bottom layer. In addition, the sampling points shall avoid the edge of the pile.
5.5.4 Whether it is dynamic sampling or static sampling, the amount of each increment
shall be basically equal, meanwhile the required quantity of an increment shall be
collected at one time as much as possible; otherwise, it will lead to unforeseen sampling
deviation.
5.5.5 Appropriate sampling equipment, tools or containers shall be used for increment
sampling.
For static sampling, a perforator can be used for powdery materials and a bucket can be
used for granular materials. When using a perforator for sampling, the perforator shall
be fully pressed into the material; an increment shall be taken for each hole. When using
a bucket for sampling, a pit shall be dug on the material pile first; the depth of the pit
shall be at least equal to half the depth of the material layer at that place; then the
material on the pit wall shall be shoveled from the bottom to the top; the material shall
not overflow from the bucket.
For dynamic sampling, if it is taken on a belt conveyor, an automatic sampling device
can be used to sweep a section of material from the moving belt, OR a section of
material can be manually swept from the belt after the belt conveyor is stopped to take
increment. If it is taken from the chute of the unloading hopper, a sampling box can be
used. When sampling from the belt, the length of the sampling section shall be greater
than 4 times the critical cake of the material; the material on the belt of the sampling
section shall be cleaned as much as possible. When taking sample with a sampling box,
it is necessary to confirm that the material is evenly discharged to form a stable material
flow; the size of the sampling box opening can intercept the complete material flow;
the depth of the sampling box is greater than the loading depth of an increment; the
particles do not pop out of the box during sampling.
5.5.6 When the particle size of the material is relatively large or there are particularly
large particles dispersed, the relevant parties may reach an agreement on the method of
taking the increment; if necessary, consider allowing large pieces to be picked up by
hand.
5.6 Synthesis of gross samples and reduction of laboratory samples
5.6.1 All the increments taken from an inspection batch are collected together and fully
mixed to form a gross sample.
5.6.2 According to the method given in Appendix E, two laboratory samples are
reduced from the mixed gross sample. The amount of a laboratory sample finally
reduced shall be controlled according to the critical cake of the gross sample; it shall
not be less than the minimum increment size specified in Table 1.
5.6.3 The number of samples in the two laboratories shall be roughly equal; the amount
of each laboratory sample shall be sufficient to prepare at least two independent test
samples for all quality characteristics to be tested. If the number of gross samples cannot
meet this requirement, the amount of each increment or the number of increments taken
can be appropriately increased.
5.6.4 Each laboratory sample shall be properly packaged, sealed, labeled to ensure that
test results of the sample are used to determine the conformity of product quality or
estimate the average quality of the product. The second sample is used as a backup
sample or duplicate sample. The second laboratory sample is tested only when there is
an objection to the test results of the first laboratory sample, or the first sample cannot
be tested due to untestable reasons. When the second laboratory sample is also tested,
the quality of the product shall be assessed by the valid test results. If the test results of
both laboratory samples are valid, the product quality is assessed by the test mean of
the two samples.
5.9.2 When the purpose of the sampling inspection is to estimate the average quality of
the product, the test results of the laboratory sample can be directly used as the
estimated value of the average quality of the product. The total precision β0 of the
sampling inspection can be calculated according to Appendix C.
5.9.3 If the purpose of the sampling inspection is to determine the acceptability of the
product, meanwhile there are clear requirements for the risk quality of both parties, the
standard deviation of the sampling inspection can be calculated according to Appendix
C; then the product quality determination rules can be determined, by negotiation
between the two parties, according to the methods given in GB/T 22555 or other
statistical standards.
5.9.4 If the purpose of sampling inspection is to determine the acceptability of the
product, where there is no other special agreement between the two parties and the
standard deviation of the sampling inspection is difficult to obtain, the mean value of
the quality characteristic test results of the samples taken can be directly compared
with the mean of the required product qualified quality batch µ0L or µ0U, to determine
the quality of the product:
When the lower specification limit of batch mean is not suitable, ≥ µ0L, it determines
that the characteristic is qualified; otherwise, it is judged to be unqualified.
When the upper specification limit of batch mean is not suitable, ≤ µ0U, it
determines that the characteristic is qualified; otherwise, it is judged to be unqualified.
When the double-sided limit is required, µ0L ≤ ≤ µ0U, it determines that the
characteristic is qualified; otherwise, it is judged to be unqualified.
If all the quality characteristic values that shall be inspected for the product meet the
requirements, THEN the product quality is judged to be qualified; otherwise, the
product is judged to be unqualified.
5.9.5 When judging the quality of a product based on a direct comparison between the
sample quality characteristic testing result and the product quality requirement
value µ0L or µ0U, the significant figures or decimal places of the test result shall be
rounded to the same as the product quality requirement value μ0L or μ0U in accordance
with GB/T 8170.
5.9.6 For products that are judged to be unqualified, the both parties may agree to treat
them as downgraded products or adopt other treatment methods.
6 Sampling inspection of packaged particle size graded
materials
6.1 Sampling inspection procedure
The sampling inspection of packaged refractory raw materials shall be carried out
according to the procedure shown in Figure 2. The specific steps are as follows:
a) Divide into batches according to varieties and particle sizes;
b) Take unit packages as sampling units; randomly select nC unit packages;
c) Take each unit package as a laboratory sample, OR obtain a laboratory sample
from each unit package by taking increment and synthesize composite sample
respectively from each unit package; obtain a total of nC laboratory samples;
d) Test each quality characteristic of each laboratory sample separately; test nT
samples for each characteristic;
e) Calculate the test mean of nT test samples contained in each laboratory sample;
use it as the test result of the corresponding laboratory sample;
f) Evaluate the quality of the batch product based on the mean test result of each
quality characteristic of nC laboratory samples.
6.2 Group-batching
Packaged refractory raw materials shall be inspected in batches according to the
following requirements:
a) Products of the same particle size processed from raw materials of the same variety,
designation, production conditions can be grouped into one inspection batch;
6.3 Extraction of unit packages
6.3.1 Take the unit package as the sampling unit, to take nC unit packages at a time by
dynamic sampling or static sampling.
6.3.2 When taking unit packages by dynamic sampling, the entire inspection batch can
be divided into nC roughly equal parts according to the loading and unloading time
interval; take one unit package from each part. The taking time point of the first unit
package is randomly determined; the taking time points of the unit packages of each
part are distributed at equal intervals.
6.3.3 When taking unit packages by static sampling, the entire inspection batch can be
divided into nC roughly equal parts in number according to the stacking area of the
product; take one unit package from each part. It is best to have the taken nC unit
packages staggered in the upper and lower layers of the material stack.
6.3.4 If the unit packaging is damaged or the sampling is not representative enough, the
sampling personnel may select another unit packaging at the adjacent position to replace
the damaged unit packaging.
6.3.5 The number of unit packaging nC that shall be sampled for a batch of products is
mainly determined by the precision of the test results expected to be achieved by the
sampling inspection and the standard deviation of the quality characteristics of the unit
packaging sampling. The relevant parties can determine the value of nC by setting the
precision of the expected sampling test results before sampling. If the relevant parties
do not set the precision of the expected sampling test results, the following sampling
scheme can generally be used:
a) When the requirements for inspection precision is not high, nC = 3 unit packaging
is sampled for a batch of products at a time;
b) When the inspection precision is required to be high, nC = 9 unit packaging is
sampled for a batch of products at a time.
When selecting the n = 9 sampling scheme, it shall be clearly stated in the requirements
for product sampling inspection in advance.
6.4 Taking of unit package samples
6.4.1 If the unit package weight is small (usually not more than 50 kg), each unit
package taken can be used as a laboratory sample intact. If the unit package weight is
large, a laboratory sample shall be collected from each unit package taken, by taking
increments and synthesizing them into unit package composite sample.
6.4.2 When taking increments from each unit package extracted to synthesize the unit
package composite sample, the minimum increment size shall be controlled according
to the critical cake of the product in accordance with the requirements of 5.3 and comply
with the provisions of Table 1.
6.4.3 When taking increments from each unit package to synthesize the unit package
composite sample, the minimum number of increments taken shall be determined
according to Table 2. Here, m0 shall be the unit package weight. Considering that the
weight of the material in the unit package of the packaged particle size graded material
is usually not more than 5 t and the quality is relatively uniform, it can be seen from
Table 2 that when CV ≤ 5%, the minimum number of increments taken from each unit
package shall usually be not less than 4.
6.4.4 It is best to use a special sampling tool to take the increments. The sampling points
of increments shall be evenly and staggered on the upper and lower layers of the unit
package, meanwhile the amount of each increment shall be roughly equal.
6.4.5 The increments taken from each unit package shall be mixed respectively
according to the unit package from which they came. One unit package corresponds to
one composite sample.
6.4.6 Divide each fully mixed composite sample into two equal parts, using one part as
a laboratory sample and the other part as retained sample.
6.4.7 The number of composite samples for each unit package shall be able to meet the
needs of at least two independent test sample preparations for all quality characteristics
to be tested. If the amount of laboratory samples taken according to the above sampling
requirements cannot meet the requirements, the number of increments or the amount of
each increment can be appropriately increased.
6.4.8 Each unit package composite sample shall be properly packaged, sealed, labeled
to ensure that the performance to be tested does not change during storage and
transportation and the labeling is clear and complete.
6.5 Laboratory sampling, test sample preparation, testing
Laboratory sampling shall be carried out in accordance with the provisions of 5.7.
The test sample preparation and testing shall be carried out in accordance with the
provisions of 5.8.
6.6 Product quality assessment
6.6.1 If the purpose of sampling inspection is to estimate the average quality of a batch
of products, the mean value of the test results of nC laboratory samples can be
directly used as the estimated value of the mean value µ of the quality characteristic of
the batch of products. The precision of the testing results can be calculated according
to the method given in Appendix C, based on the current or previous test data of the
same product (the data shall be sufficient).
6.6.2 If the purpose of sampling inspection is to determine the acceptability of the
inspection batch of products, when the nC = 3 sampling scheme is selected, the mean
value of the test results of the laboratory samples can be directly compared with the
upper specification limit of batch mean μ0U or lower specification limit of batch mean
μ0L of the batch of products to determine the conformity of the product quality. The
judgment rules are as follows:
When the lower specification limit of batch mean is not suitable, ≥ μ0L, it
determines that the characteristic is qualified; otherwise, the characteristic is judged
to be unqualified.
When the upper specification limit of batch mean is not suitable, ≤ μ0U, it
determines that the characteristic is qualified; otherwise, it is judged to be
unqualified.
When the double-sided limit is required, μ0L ≤ ≤μ0U, determines that the
characteristic is qualified; otherwise, it is judged to be unqualified.
If all the quality characteristic values that shall be inspected for the product meet the
requirements, the product quality is judged to be qualified. Otherwise, the product is
judged to be unqualified.
6.6.3 If the purpose of sampling inspection is to determine the acceptability of the
inspection batch products, when the selected sampling scheme is nC = 9, the conformity
of the single quality characteristic of the product is determined according to the
following rules:
When the lower specification limit of batch mean is not suitable, ≥ μ0L - 0.62S,
it determines that the characteristic is qualified; otherwise, it is judged to be
unqualified.
When the upper specification limit of batch mean is not suitable, ≤ μ0U + 0.62S,
it determines that the characteristic is qualified; otherwise, it is judged to be
unqualified.
When the double-sided limit is required, μ0L - 0.62S ≤ ≤μ0U + 0.62S, it
determines that the characteristic is qualified; otherwise, it is judged to be
unqualified.
If the quality characteristic values of all products to be inspected meet the requirements,
the product quality is judged to be qualified; otherwise, the product is judged to be
unqualified.
Appendix C
(Normative)
Calculation of standard deviation and precision of sampling inspection
C.1 Inspection procedures and conditions
When the standard deviation of each process of sampling inspection of a certain quality
characteristic of refractory raw materials is unknown, several batches of the same
products can be sampled and inspected according to the procedures and requirements
set below, to calculate the standard deviation of each process of product sampling
inspection.
a) Inspect N batches of the same product; take nI increments for each batch of bulk
products; take nC unit package composite samples from each batch of packaged
products;
b) Reduce nP subsamples from each increment or unit package composite sample;
c) Prepare and test nT test samples in parallel for each subsample.
When the above procedure is used, the larger the value of N, nI or nC, nP, nT, the more
accurate the estimated value of standard deviation and precision is; at least N × nI ≥ 20
or N × nC ≥ 20, nP ≥ 2, nT ≥ 2 shall be achieved.
In addition, for the convenience of measurement, this document also requires: the
number of increments nI taken from each batch of bulk products is equal; the number
of unit packages nC taken from each batch of packaged products is equal; the number
of subsamples nP taken from each increment or unit package composite sample is equal;
the number of test samples nT prepared and tested from each subsample is equal; each
laboratory reports only one test result for each test sample.
C.2 Measurement standard deviation σM
When a laboratory tests the same sample, the standard deviation obtained from multiple
inconsistent measurement results, due to the uncertainty of the measurement itself, is
called the measurement standard deviation σM. σM is a component of the total standard
deviation of the final sampling inspection result. If the testing standard gives the
allowable difference r between two independent tests of the same sample in the same
laboratory, the value of σM can be estimated according to formula (C.1). If the testing
standard does not give the test deviation requirements, the laboratory can estimate the
value of σM according to statistical methods based on the data of several independent
tests of the same test sample.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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