GB/T 17445-2022 PDF English
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| GB/T 17445-2022 | English | 245 |
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Cast grinding balls
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| GB/T 17445-2009 | English | 439 |
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Cast grinding balls
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| GB/T 17445-1998 | English | 359 |
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GB/T 17445-2022: Cast grinding balls---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT17445-2022
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.80
CCS J 31
Replacing GB/T 17445-2009
Cast Grinding Balls
铸造磨球
ISSUED ON: MARCH 9, 2022
IMPLEMENTED ON: OCTOBER 1, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative References ... 5
3 Terms and Definitions ... 6
4 Designation and Code ... 7
5 Technical Requirements ... 8
6 Test Method ... 10
7 Inspection Rules ... 11
8 Marking, Certificate of Conformity, Packaging and Transportation ... 12
Appendix A (Normative) Test Method of Impact Fatigue Life of Grinding Ball ... 14
Appendix B (Normative) Determination and Calculation of Breakage Ratio of Ball 17
Appendix C (Normative) Calculation of Ball Consumption of Cast Grinding Ball ... 18
Cast Grinding Balls
1 Scope
This Document specifies the designations and codes, technical requirements, test methods,
inspection rules, markings, certificates, packaging and transportation of chromium alloy white
cast iron grinding balls and ductile iron grinding balls for drum mills.
This Document is applicable to chromium alloy white cast iron grinding balls and ductile iron
grinding balls (hereinafter referred to as "grinding balls") used for crushing and grinding ore,
coal, cement and other related materials in the metallurgical, electric power, building materials
and chemical industries.
2 Normative References
The provisions in following documents become the essential provisions of this Document
through reference in 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 Document.
GB/T 223.3 Methods for chemical analysis of iron, steel and alloy; The diantipyrylmethane
phosphomolybdate gravimetric method for the determination of phosphorus content
GB/T 223.4 Alloyed steel - Determination of manganese content - Potentiometric or visual
titration method
GB/T 223.11 Iron, Steel and Alloy - Determination of Chromium Content - Visual Titration
or Potentiometric Titration Method
GB/T 223.18 Methods for Chemical Analysis of Iron, Steel and Alloy - The Sodium
Thiosulfate Separation Iodometric Method for the Determination of Copper Content
GB/T 223.23 Iron, Steel and Alloy-Determination of Nickel Content - The
Dimethylglyoxime Spectrophotometric Method
GB/T 223.26 Iron, Steel and Alloy - Determination of Molybdenum Content - The
Thiocyanate Spectrophotometric Method
GB/T 223.60 Methods for chemical analysis of iron, steel and alloy - The perchloric acid
dehydration gravimetric method for the determination of silicon content
GB/T 223.63 Methods for chemical analysis of iron, steel and alloy - The sodium
(potassium) periodate photometric method for the determination of manganese content
GB/T 223.71 Methods for Chemical Analysis of Iron, Steel and Alloy - The Gravimetric
Method after Combustion in the Pipe Furnace for the Determination of Carbon Content
GB/T 223.72 Iron, Steel and Alloy - Determination of Sulfur Content - Gravimetric
Method
GB/T 230.1 Metallic materials - Rockwell hardness test - Part 1:Test method
GB/T 5611 Foundry terminology
GB/T 5612 Code for representing cast iron
GB/T 8170 Rules of rounding off for numerical values & expression and judgment of
limiting values
GB/T 9441-2009 Metallographic test for spheroidal graphite cast iron
GB/T 20066 Steel and Iron - Sampling and Preparation of Samples for the Determination
of Chemical Composition
GB/T 24234 Cast iron - Determination of multi-element contents - Spark discharge atomic
emission spectrometric method (Routine method)
3 Terms and Definitions
For the purposes of this Document, the following terms and definitions given in GB/T 5611
apply.
3.1 Chromium alloy white cast iron grinding ball
Grinding balls that are cast from white cast iron with chromium as the main alloying element.
3.2 Ductile iron grinding ball
Grinding balls that are made of ductile iron.
3.3 Breakage ratio of ball
The percentage of the total weight of broken balls to the total weight of used balls.
NOTE: Broken balls refer to grinding balls whose broken area exceeds 1/3 of the surface area of the
grinding balls during normal production operation of the mill.
3.4 Impact fatigue life of grinding ball
The number of impacts that a grinding ball sustains, when it fails due to impact fatigue,
measured in a drop ball test.
5.3.4 Whether the Impact fatigue life of grinding ball and ball consumption are used as
acceptance items shall be agreed upon by the supplier and the purchaser.
5.4 Surface quality
Grinding balls should not have cracks and casting defects such as slag inclusions, sand holes,
shrinkage cavities, shrinkage, pores, cold shuts, etc. that affect the performance.
5.5 Metallographic structure
5.5.1 The metallographic structure of chromium alloy white cast iron grinding balls and ductile
iron grinding balls is not used as an acceptance item for products. If there are special needs, it
shall be agreed upon by the supplier and the purchaser.
5.5.2 The graphite spheroidization level of ductile iron grinding balls shall be no lower than
Level-3 specified in GB/T 9441-2009. The number of graphite balls shall be no less than 100
piece/mm2. If there are special requirements, the spheroidization level shall be agreed upon by
the supplier and the purchaser. Other metallographic structures are not accepted as acceptance
items of the product. If there are special needs, they shall be agreed upon by the supplier and
the purchaser.
6 Test Method
6.1 The diameter of the grinding balls shall be measured with a measuring tool with an accuracy
of no less than 0.1mm.
6.2 The chemical composition analysis method shall be carried out in accordance with the
provisions of GB/T 223.3, GB/T 223.4, GB/T 223.11, GB/T 223.18, GB/T 223.23, GB/T 223.26,
GB/T 223.60, GB/T 223.63, GB/T 223.71 and GB/T 223.72.
6.3 The preparation and sampling methods of specimens for chemical composition analysis
shall comply with the provisions of GB/T 20066. The preparation and sampling of spectral
analysis specimens shall comply with the provisions of GB/T 24234.
6.4 The Rockwell hardness test shall be carried out in accordance with the provisions of GB/T
230.1. The surface hardness is allowed to be tested with a portable hardness tester.
6.5 The surface hardness shall be tested 2mm~3mm below the surface of the grinding ball. The
hardness test surface shall be machined, wire cut or electrospark machined; and the wire cut or
electrospark machined surface shall be machined to remove the heat affected zone.
6.6 Conduct impact fatigue test of grinding ball according to Appendix A.
6.7 The determination and calculation of breakage ratio of ball shall comply with the provisions
of Appendix B.
6.8 The calculation of ball consumption shall comply with the provisions of Appendix C.
7 Inspection Rules
7.1 Inspection batch
One of the following situations constitutes an inspection batch:
a) Chemical composition inspection batch: when electric furnace smelting is adopted, each
furnace is regarded as a batch; when cupola furnace smelting is adopted, every 2 h is
regarded as a batch;
b) Grinding ball diameter and hardness inspection batch: grinding balls of the same
designation cast in multiple furnaces under the condition of stable smelting process and
subjected to the same heat treatment process (if heat treatment is required), heat-treated
in intermittent heat treatment furnace, with the same nominal diameter in each furnace
are regarded as a batch; grinding balls heat-treated in continuous heat treatment furnace,
with the same nominal diameter every 10t are regarded as a batch.
7.2 Judgment rules
7.2.1 Take one specimen from each batch for chemical composition inspection. When sampling
by taking chips, chips at least 6mm below the casting surface shall be removed. If the inspection
result is unqualified, double sampling can be carried out for reinspection. If one specimen is
still unqualified, the chemical composition of the batch of grinding balls shall be judged as
unqualified.
7.2.2 Three grinding balls are randomly selected from each batch for inspection of diameter
and hardness. If the diameter or hardness of one grinding ball fails to meet the standards, the
same number of grinding balls are randomly selected for reinspection. If the number of grinding
balls that fail to meet the standards in the two inspections is greater than or equal to 2, the
diameter or hardness of the batch of grinding balls shall be determined to be unqualified. If the
diameter or hardness of two grinding balls fails to meet the standards in the first sampling, the
diameter or hardness of the batch of grinding balls shall be determined to be unqualified. If the
hardness of the grinding balls fails to meet the standards, re-heat treatment shall be allowed.
7.2.3 The inspection results of chemical composition, hardness and diameter shall be rounded
off in accordance with the provisions of GB/T 8170.
Appendix A
(Normative)
Test Method of Impact Fatigue Life of Grinding Ball
A.1 Test principle
The impact fatigue life test of grinding ball of ball drop method (hereinafter referred to as the
"ball drop test") uses a ball to drop on the fatigue test machine (hereinafter referred to as the
"ball drop test machine") to simulate the impact process of cast grinding balls in a drum mill
under laboratory conditions; calculate the number of impacts of the cast grinding balls when
they fail due to impact fatigue; and use the number of impacts when fatigue failure occurs to
represent the impact fatigue life of the cast grinding balls.
The number of impacts is displayed by a counter; and the impact fatigue life of the cast grinding
balls shall be no less than 8000 times.
A.2 Ball drop machine model
The ball drop machine model is Type-MQ, and the drop distance is 3.5m.
A.3 Specimen
The specimen for the ball drop test is a ϕ100mm grinding ball.
A.4 Number of grinding balls for the ball drop test
The specimen for the ball drop test shall be 16 cast grinding balls randomly selected from the
batch to be inspected as test balls; and 3 or more cast grinding balls shall be selected as
replacement balls; and marks shall be placed on the surface of the replacement balls.
A.5 Ball drop test temperature
The ball drop test is carried out at room temperature.
A.6 Judgment and test procedure of cast grinding balls failure
A.6.1 Test procedure
A.6.1.1 Grind the edges of the test balls and replacement balls or clean the surfaces in the
cleaning drum; and check the working status of the test machine.
A.6.1.2 First put 12 test balls into the curved pipe; start the test machine; and gradually put the
remaining 4 test balls into the circulation conveying system from the downhill slide.
A.6.1.3 Turn on the counter; reset the counter; clear the alarm; and turn the digital dial to the
preset number (8000).
A.6.1.4 The test personnel shall observe carefully on site. When it is found that one test ball
fails in accordance with the provisions of a) or b) in A.6.2, take out the failed ball and put in a
replacement ball until the third failed ball appears; and respectively record the cumulative
number of impacts received by the three test balls in the ball drop machine system when they
fail. If the number of failed balls in the test does not reach the indicator number of failed ball,
the added replacement ball has been damaged and then it shall not be counted in the number of
failed balls.
A.6.2 Failure judgment
When one of the following situations occurs, the cast grinding ball can be judged as failed:
a) The average diameter of the peeling layer on the surface of the cast grinding ball (the
average of the maximum and the minimum diameter) is greater than 20mm; and
meanwhile the thickness in the middle is greater than 5mm;
b) The cast grinding ball is broken along the middle.
A.7 Impact fatigue test life of grinding ball
The impact fatigue test life of grinding ball is determined according to Formula (A.1):
Where:
Nf – Impact fatigue test life (number of times) of this batch of grinding balls;
Bt – The number of cast grinding balls in the curved pipe;
Bs – The total number of cast grinding balls in the test system;
N1 – The number of times recorded by the counter when the first test ball fails;
N2 – The number of times recorded by the counter when the second test ball fails;
N3 – The number of times recorded by the counter when the third test ball fails.
A.8 Data processing
When processing data, the decimal part shall be filled in the test report with integer value
according to the numerical rounding rules of GB/T 8170.
......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
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