GB/T 18838.3-2008 English PDF (GB/T18838.3-2008)

GB/T 18838.3-2008: Preparation of steel substrates before application of paints and related products -- Specifications for metallic blast-cleaning abrasives -- Part 3: High-carbon cast-steel shot and grit
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GB/T 18838.3-2008
Preparation of steel substrates before application of paints and related products.Specifications for metallic blast-cleaning abrasives.Part 3. High-carbon cast-steel shot and grit
ICS 25.220.10
A29
National Standards of People's Republic of China
GB/T 18838.3-2008/ISO 11124-3.1993
Coating steel surface treatment before coating
Technical requirements for blast cleaning metal abrasives
Part 3. High Carbon Cast Steel Balls and Sand
(ISO 11124-3.1993, IDT)
Posted on.2008-04-01
2008-09-01 Implementation
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
China National Standardization Administration released
Foreword
GB/T 18838 "Technical Requirements for Metallic Abrasives for Surface Cleaning of Steel Sheets Prior to Coating Coatings" is divided into the following sections.
--- Part 1. Guidelines and classifications;
--- Part 2. Chilled cast iron sand;
---Part 3. High-carbon cast steel balls and sand;
---Part 4. Low-carbon cast steel pellets;
--- Part 5. Wire section.
This part is part 3 of GB/T 18838.
This section is equivalent to the technical requirements of ISO 11124-3.1993 "Applying Metal Abrasives for Spray Cleaning of Steel Surfaces before Coatings."
Part 3. High Carbon Cast Steel Balls and Sand (English Edition).
This section is equivalent translation ISO 11124-3.1993.
For ease of use, this section made the following editorial changes.
--- The term "this international standard" is replaced by "this part";
---Replace the comma "," as a decimal point with a decimal point ".";
--- Use the "," instead of the comma "," as a statement;
--- Increased the list of Table 3;
--- Deleted the foreword of international standards.
Appendix A and Appendix B of this section are informative annexes.
This part is proposed by China State Shipbuilding Corporation.
This part is under the jurisdiction of the Technical Committee of Metal Surface Treatment and Painting Technology before painting by the National Standardization Technical Committee for Coatings and Pigments.
This section was drafted by. China National Shipbuilding Industry Comprehensive Technology and Economic Research Institute, the 11th Institute of China Shipbuilding Industry, Shandong Kaitai Metal
Abrasives Co., Ltd., Shandong University.
The main drafters of this section. Song Yanyuan, Liu Bingyang, Fu Jianhua, Liu Ruwei, Wang Ruiguo, Song Qingan.
GB/T 18838.3-2008/ISO 11124-3.1993
Coating steel surface treatment before coating
Technical requirements for blast cleaning metal abrasives
Part 3. High Carbon Cast Steel Balls and Sand
Warning. The abrasives, materials and equipment used for surface treatment may be dangerous if used carelessly. Many countries have during use
Or after use (waste management) materials and abrasives that are considered to be dangerous, such as. free silicon, carcinogens or toxic substances, have been specified. because
Therefore, these regulations should be observed. It is important to ensure that appropriate guidance and all required preventive measures are implemented.
1 range
This part of GB/T 18838 specifies 14 grades of high carbon cast steel shots for blast cleaning and 12 grades of high carbon cast steel sanders.
Material requirements, including hardness, density, defects and structural requirements, and chemical composition.
The requirements of this part of ISO /IEC 18838 apply only to abrasives that have not been used, and do not apply to used abrasives.
The test method for blast cleaning metal abrasives is shown in various parts of GB/T 19816.
High-carbon cast steel pellets and sand are recyclable and reusable abrasives that can be used both in fixed and on-site injection equipment.
Note 1. Refer to Appendix A and Appendix B for a list of commonly used standards for metal abrasives in the world and their relationship with this standard.
Note 2. Although this part of the GB/T 18838 is specifically formulated to meet the surface treatment requirements of steel structures, the specified characteristics are generally applicable to
Surfaces or components of other materials treated with jet cleaning techniques. These provisions are already in ISO 8504-2.20001) "Coating the surface of steel before coating
Surface Treatment Methods Part 2. Abrasive blast cleaning.
2 Normative references
The clauses in the following documents are quoted in this part of GB/T 18838 and become the terms of this part. Any quoted text
Any subsequent amendments (not including errata content) or revisions do not apply to this section, however, it is encouraged to achieve
The parties to the agreement study whether the latest versions of these documents can be used. For undated references, the latest edition applies to this
section.
GB/T 19816.1-2005 Preparation of steel substrates before application of paints. Test methods for spray-cleaning metal abrasives. Part 1.
Sampling (ISO 11125-1.1993, IDT)
GB/T 19816.2-2005 Preparation of steel substrates before application of paints. Test method for metal abrasives for blast cleaning. Part 2.
Determination of particle size distribution (ISO 11125-2.1993, IDT)
GB/T 19816.3-2005 Preparation of steel substrates before application of paints - Test methods for spray-cleaning metal abrasives - Part 3.
Determination of hardness (ISO 11125-3.1993, IDT)
GB/T 19816.4-2005 Preparation of steel substrates before application of paints. Test methods for spray-cleaning metal abrasives. Part 4.
Determination of apparent density (ISO 11125-4.1993, IDT)
GB/T 19816.5-2005 Preparation of steel substrates before application of paints. Test methods for spray-cleaning metal abrasives. Part 5.
Defective particle percentage and microstructure determination (ISO 11125-5.1993, IDT)
GB/T 19816.6-2005 Preparation of steel substrates before application of paints - Test methods for spray-cleaning metal abrasives - Part 6.
Determination of Foreign Impurities (ISO 11125-6.1993, IDT)
GB/T 19816.7-2005 Preparation of steel substrates before application of paints. Test method for spray-cleaning metal abrasives. Part 7.
Determination of water content (ISO 11125-7.1993, IDT)
1) This standard is ISO 8504-2.1992 in ISO 11124-3.1993. GB/T 18839.2-2002 uses ISO 8504-2.2000 as a modification.
ISO 439.1982 Determination of the total silicon content of steel and cast iron gravimetric method
GB/T 18838.3-2008/ISO 11124-3.1993
ISO 629.1982 Determination of manganese content in steels and cast irons - Spectrophotometric method
ISO 4935.1989 Determination of steel and iron-sulfur content Infrared absorption after combustion in induction furnaces
ISO 9556.1989 Determination of the total carbon content of steel and iron. Infrared absorption after combustion in induction furnaces
ISO 10714.1992 Determination of steel and iron phosphorus content Phosphorus vanadium molybdate spectrophotometric method
3 Definitions
The following definition applies to this part of GB/T 18838.
3.1
A blast-cleaning metal abrasive that melts high-carbon steel by atomizing a pelletized (see 3.3) cast processed product.
3.2
A blast-cleaning metal abrasive made by crushing sharp-edged horn particles of various sizes of high-carbon cast steel pellets.
3.3
The main shape is circular, its length is not more than twice the maximum particle width, and there are no edges, broken sections and other sharp surface defects
particle.
3.4
The main shape is an angular shape, with a broken section and sharp edges, and the section size is smaller than half of the cross-section particles.
3.5
Abrasive cavities, shrinkage holes, cracks, or irregular shape of particles, if greater than or equal to the specified value, will be harmful to the abrasive performance
(See Table 3).
3.5.1
The smooth surface of the inner hole, the area of not more than 10% of the cross-section of the inner hole.
3.5.2
Pores with a rough dendritic surface or microporous region, the area of which is not more than 40% of the cross-section of the particle.
3.5.3
Line-shaped non-continuous defects, having an aspect ratio of 3.1 or greater, a length exceeding 20% of the diameter or the minimum size of the particles, and being present
Radial.
3.6
Non-magnetic, any material or particle that is not in the abrasive particles but is mixed in the abrasive.
4 Abrasive marking
High-carbon cast steel pellets and sand should be marked with "abrasive GB/T 18838" and the abbreviated letter "M/HCS" representing metallic high-carbon cast steel abrasive.
The identification, followed by the label required to buy the pellet shape or sand grain symbol "S" or "G", the final mark indicates the required grade or particle mark
Three digits of the size. If the hardness of the abrasive can be selected, the required particle Vickers hardness (HV) range should be specified.
Example 1.
Abrasive GB/T 18838M/HCS/S140
Said high-carbon steel-type metal abrasive, in line with the requirements of this part of GB/T 18838, the initial particle shape is pellets, grade is 140 (ie, the nominal particle size is
GB/T 18838.3-2008/ISO 11124-3.1993
1.40mm).
Example 2.
Abrasive GB/T 18838M/HCS/G140/570-710HV
Said high-carbon steel-type metal abrasive, in line with the requirements of GB/T 18838 of this part, the initial particle shape is grit, grade is 140 (ie, the nominal particle size is
1.40mm), hardness range from 570HV to 710HV.
It is necessary to mark this complete product mark on the order form.
Note 1. Table 1 and Table 2 show the grade requirements and code requirements. The grade code is an intermediate approximation or nominally straight representing a range of particle sizes for each grade.
The number of the path is expressed in millimeters multiplied by 100.
Note 2. Appendix A provides approximately equivalent grades and codes in other national standards commonly referenced for casting metallic abrasives.
5 Sampling
Sampling according to the provisions of GB/T 19816.1-2005.
6 Requirements for High Carbon Cast Steel and Sand Abrasives
The requirements for high-carbon cast steel pellets and sand abrasives are as specified in Table 3.
7 Packing and batch number signs
All supplies should be clearly marked and identified in accordance with Chapter 4. Sales units (such as containers, barrels, boxes, etc.) should clearly
The complete product code label is affixed and, if possible, the hardness range.
Subpackages (eg bags) should mark the shape and grade codes of the particles.
Note. It is recommended that the packaging mark should include additional marks that can be traced to a specific product cycle or batch number, at least in containers, barrels or boxes, etc.
Should include traceable signs.
8 Information Provided by Manufacturers and Suppliers
When necessary, the manufacturer or supplier shall provide a test report detailing the results of determining the relevant properties in accordance with the methods specified in Table 3.
GB/T 18838.3-2008/ISO 11124-3.1993
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GB/T 18838.3-2008/ISO 11124-3.1993
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GB/T 18838.3-2008/ISO 11124-3.1993
Table 3 Performance requirements for high carbon cast steel pellets and sand abrasives
Performance requirements test methods
Grades are shown in Table 1 and Table 2 GB/T 19816.2-2005
hardness
The hardness of 90% of the tested particles should be within one of the following ranges.
Standard hardness.
Pellets. 390HV to 530HV
Sand grains. 390HV to 530HV
470HV～610HV
570HV～710HV
≥700HV
Special hardness (pellets and grit). Other hardness ranges can be determined by the ordering party, but at least
90% of the particle hardness difference is within about 140HV.
Abrasives sometimes contain recessive internal shrinkage defects or voids that exist beneath the polished sample surface.
Holes, which will cause some uneven hardness indentations, giving an erroneous hardness reading.
When testing, these readings should be discarded
GB/T 19816.3-2005
Apparent density ≥ 7.0 × 103kg/m3 (7.0kg/dm3) GB/T 19816.4-2005
Defects (see 3.5)
Particle shape
a) Pellet
b) Sand grains
Cavity
Shrinkage hole
crack
a) Pellet
b) Sand grains
Total amount of defects
a) Pellet
b) Sand grains
The number of defective particles in the measured particles shall not exceed the following provisions.
Non-spherical particles no more than 5%
In sands with a hardness of not more than 700 HV, the number of pellets or more than hemispherical pellets does not exceed
10%, in the sand particles with a hardness greater than 700 HV, the number of pellets or particles exceeding the hemispherical shape is not exceeded
Over 5%
≤10%
≤10%
≤15%
≤40%
≤20%
≤40%
Particles with more than one of the above defects are counted only once in the total amount of defects
GB/T 19816.5-2005
Foreign impurities (including
Slag
The mass fraction is not more than 1% GB/T 19816.6-2005
GB/T 18838.3-2008/ISO 11124-3.1993
Table 3 (continued)
Performance requirements test methods
Microstructure
High-carbon cast steel and sand abrasives should have uniform martensitic and/or bainite microstructures and heat
Treated to the same extent as the hardness, with fine and evenly distributed carbides. Due to high temperatures
Transformation of formed products such as partial decarburization, network carbides, and dendritic grain boundary segregation of pearlite
It is undesirable.
The number of measured particles with this unwanted microstructure should not exceed 15%
GB/T 19816.5-2005
chemical composition
Carbon. 0.8% to 1.2% mass fraction <...