This standard specifies the visual assessment grade of the rust degree and rust removal quality of steel surfaces before painting. It is applicable to hot-rolled steel surfaces that have been treated by spray or blasting, manual and power tool rust removal, and flame rust removal. The assessment of the rust removal grade of cold-rolled steel surfaces can also be used as a reference. This standard is equivalent to the international standard ISO8501-1:1988 "Pretreatment of steel before application of paint and related products - Visual assessment of surface cleanliness - Part 1: Rust grade and rust removal grade of unpainted steel and steel after complete removal of the original coating." GB 8923-1988 Rust grade and rust removal grade of steel surfaces before painting GB8923-1988 Standard download decompression password: www.bzxz.net

UDC 669.14: 620.191
National Standard of the People's Republic of China
GB 8923-88
Rust grades and preparation grades of steel surfaces before application of paints and related products1988-03-21Published
Implemented on 1989-03-01
Published by the State Administration of Technical Supervision
WNational Standard of the People's Republic of China
Rust grades and preparation grades of steel surfaces before application of paints and related productsUDC 669.14:620.191
GB8923-88
This standard specifies the visual assessment grade of the rust removal quality of steel surface before painting. It is applicable to the hot-rolled steel surface treated by spraying or blasting, rust removal by tools and power tools, and rust removal by ignition. The assessment of the rust removal grade of cold-rolled steel surface is also used as a reference.
This standard is equivalent to the international standard ISO8501-1:1988 "Pretreatment of steel before painting and related products - Visual assessment of surface cleanliness Part 1: Rust grade and rust removal grade of unpainted steel and steel after complete removal of the original coating". 1 General
1.1 This standard divides the original rust degree of the uncoated steel surface into four "rust grades", and divides the quality of the uncoated steel surface and the steel surface after rust removal from all coatings into ten "rust removal grades". The rust grade and rust removal grade of the steel surface are determined by the description and photos of typical samples. 1.2 This standard expresses the rust grade and rust removal grade by the visual appearance of the steel surface. When evaluating these grades, they should be observed directly under moderate lighting conditions without the aid of a microscope or other instruments. 2 Rust Grades
The four rust grades of the steel surface are represented by A, B, C and D respectively. Typical sample photos of these corrosion grades are shown in Chapter 5, and the description is as follows:
A Steel surface completely covered with scale and almost free of rust; B Steel surface already rusted and with some scale peeled off; B Steel surface with scale peeled off due to rust or scraped off and with a small amount of pitting; H Steel surface with scale peeled off due to rust and generally pitting. 3 Rust removal grades
3.1 General
The rust removal grade of a steel surface is indicated by the letter "Sa", "S" or "F1" representing the rust removal method used. If there is a Arabic numeral after the letter, it indicates the degree of removal of attachments such as scale, rust and paint coating. Steel: The textual description of the surface derusting grade is given in 3.2, 3.3 and 13.4. The typical sample photos of these grades are given in 5, 3.1.2
Note: (1) In the definitions of the derusting grades in this chapter, the term "adherence" may include welding slag, welding spatter, soluble salts, etc. (2) In this chapter, when the amine scale, rust or paint coating can be peeled off from the steel surface with a metal scraper, it should be considered as loosely attached.
3.2 Derusting by blasting or blasting
3.2.1 Derusting by blasting or blasting is indicated by the letter \Sa. 3.2.2 Before derusting by blasting or blasting, the rust layer should be scraped off. Visible grease and dirt should also be removed. After derusting by blasting or blasting, the steel surface should be free of loose dust and debris.
Approved by the State Administration of Technical Supervision on March 21, 1988, and implemented on March 1, 1989
1
GB 8923-88
3.2.3 For steel surfaces that have been derusted by spraying or blasting, this standard has four levels of derusting. The text is as follows: Sal Mild spraying or blasting derusting
The steel surface should be free of visible grease and dirt, and free of loosely attached scale, rust, paint coating and other attachments. See photos BSa1, CSSa1 and DSSa1. Si2 Thorough spraying or blasting derusting
The steel surface should be free of visible grease and dirt, and the scale, rust, paint coating and other attachments have been basically removed, and the H residue should be completely attached. See photos BSa2, CSa2, and DSa2uSa2 Very thorough blasting or blasting will leave the steel free of visible deposits of grease, dirt, scale, rust, and paint. Any remaining traces will be only slight spots or streaks of color. See photos ASa2, BSa27, CSa2±, and LSa2≠Sa3 Clean steel blasting or blasting will leave the steel free of visible deposits of grease, dirt, scale, rust, and paint. The surface will show a uniform metallic color. See photos ASa3, BS±3, CSu3, and LSa3 3.3 Rust removal by power tools 3.3.t Rust removal by hand and power tools, such as shovels, hand or wire brushes, powered sandpaper discs or wheels, is indicated by the letter \st\.
3.3.2 Before manual and power tool rust removal, the original rust layer should be scraped off, and visible grease and dirt should also be removed. After manual and power tool rust removal, the steel surface should be cleaned of dust and debris. 3.3.3 For the steel surface rusted by manual and power tools, the standard stipulates two rust removal levels, which are described as follows: St2 Thorough manual and power tool rust removal
The steel surface should be free of visible grease and dirt, and no loose oxide scale, rust and paint coating and other attachments, see RSt2, CSt2 and LSt2.
St3 Very thorough manual and power tool rust removal The steel surface should be free of visible grease and dirt, and no loose oxide scale, rust and paint coating and other attachments. Rust removal should be more thorough than St3, and the surface of the exposed part of the substrate should have a metallic luster. See photos BSt3, CSt3 and DS13. 3.4 Flame rust removal
3.4.1 Flame rust removal is indicated by the letters \FI\. 3.4.2 Before flame rust removal, thick rust layers should be removed. Flame rust removal should include the use of a powered wire brush to remove the products of heating attached to the steel surface during the flame heating operation.
3.4.3 The rust removal level after flame rust removal is described as follows: FI Flame rust removal
The steel surface should be free of attachments such as scale, rust and paint coating. Any remaining traces should only be surface discoloration (different color shadows). See photos AFI, HFI, CFI and DFI. GB 8923-88bzxz.net
4 Visual assessment of the rust grade and rust removal grade of steel surfaces 4.1 The assessment of the rust grade and rust removal grade of steel surfaces should be carried out under good diffuse light or under artificial lighting conditions of equivalent illumination. The inspectors should have normal vision. 4.2 The steel surface of the inspected piece should be visually compared with the corresponding photograph (see Chapter 1). The photograph should be close to the steel surface. 4.3 When assessing the rust grade, the rust grade indicated in the photograph of the corresponding more serious rust grade shall be used as the assessment result; when assessing the rust removal grade, the rust removal grade indicated in the photograph that is closest to the steel surface appearance shall be used as the assessment result. Note: (1) There are many factors that affect the visual assessment results of the rust removal grade of steel surfaces, the main ones of which are: 1. The abrasive used for spraying or projectile rust removal, which is used for work and power tools. a. The process used for rust removal; b. The rust condition of the steel surface that does not belong to the standard rust grade; c. The color of the steel itself:
d. The difference in roughness of each part due to different corrosion degrees; e. Surface unevenness, such as pitting;
fT Tool scratches:
. Uneven lighting;
1. The shadow caused by the different angles of the abrasive impacting the surface during spray or projectile rust removal i. Abrasive embedded in the surface.
Visually assess the rust removal grade of the originally painted steel surface. The instrument can use photos with rust grade symbols C and D (2)
such as DSa2 or CSa2+). Which one to choose (for example, DSa2 or CSa2±) depends on the degree of pitting on the steel surface (see Chapter 2). Photos
5.1 This standard includes 28 typical sample photos of steel surface corrosion levels, which correspond to the photos in the international standard IS08501-1:1988. In case of disagreement, the photos in ISOS501-1 shall be used as the basis for judgment. 5.1.1 There are 4 photos showing the corrosion levels, marked A, B, C and TD5.1.2. There are 24 photos showing the rust removal grades achieved by blasting or projectile removal, manual and power tool rust removal, and flame rust removal. These photos are marked with symbols for the original rust grade before rust removal and the rust removal grade after rust removal, such as BSa2: 5.2 The 14 photos of blasting or projectile removal show the surface condition of steel after blasting or projectile removal with quartz sand abrasives. The surface of steel after blasting or projectile removal with other types of abrasives may have different colors. 5.3 This standard does not include photos of ASal, ASu2, ASt2 and AS3. 5.4 Typical sample photos of rust grade and rust removal grade are arranged in the order shown in the figure below and are an integral part of the standard. Rust grade:
W4
Rust removal grade:
Rust removal by jetting
Rust removal by hand and power tools
Rust removal by fire
ASa2→
GB 8923-88
Order of typical sample photos
Additional notes:
This standard is proposed by China State Shipbuilding Corporation and the Ministry of Railways. This standard is under the jurisdiction of the National Technical Committee for Standardization of Paints and Pigments, Metal Surface Treatment before Painting and Painting Technology Sub-Committee. This standard is issued by the Ship Technology Research Institute of China State Shipbuilding Corporation and the Qishuyan Locomotive and Rolling Stock Technology Research Institute of the Ministry of Railways. The Wuhan Forestry Protection Research Institute of the Machinery Commission and the Nanjing Water Conservancy Science Research Institute of the Ministry of Water Resources and Hydropower are responsible for the drafting of the standard. Institute, China Petrochemical Corporation Shanghai Chemical Plant Research Institute, Ministry of Railways Standard Metrology Institute, Ministry of Aerospace 6991 participated: This standard was drafted by Hong Dongyu, Liu Panxing, Lu Xiankang, Chen Shuigen, Ge Zhenchao, Wei Zhonggen, Boer, and Sun Jianming. WA
W.ASa2
BSa1
Sa1
W.DSa1
DSa2/2
W.BSt2
W.DSt2
W.
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.