This standard specifies the original rust level of the ship repair hull surface and the visual quality assessment level and assessment method of rust removal on the ship repair hull surface by spraying, manual, power tool and mechanical grinding. This standard is applicable to the rust removal quality assessment of various steel operating ship hull parts. CB 3375-1991 Ship repair hull rust removal quality requirements CB3375-1991 standard download decompression password: www.bzxz.net

Shipbuilding Industry Standard of the People's Republic of China
CB3375-91
Quality requirements for rust removal on ship repair hulls
Published on November 8, 1991
Implementation on July 1, 1992
China State Shipbuilding Corporation
Shipbuilding Industry Standard of the People's Republic of China
CB 3375--91
Quality requirements for rust removal on ship repair hulls
Classification number: R31
1 Subject content and scope of application
This standard specifies the original rust grade on the surface of the ship repair hull and the visual quality assessment grade and assessment method for rust removal on the surface of the ship repair hull by spraying, manual, power tool and mechanical grinding.
This standard is applicable to the rust removal quality assessment of the hull parts of various steel operating ships.
2 Reference standards
Approved by China State Shipbuilding Corporation on November 8, 1991, and implemented on July 1, 1992 GB 8923
3 Terminology
CB 3375---91
Surface rust grade and rust removal of steel before painting 3.1 Rust removal by spraying
Surface rust removal by spraying abrasives (sand, metal slag particles, iron shots, steel shots, steel wire particles, etc.) onto the surface of steel using compressed air as the power. Indicated by "Sa". 3.2 Manual and power tool rust removal
Rust removal on the steel surface is carried out by manual or power tools, such as scrapers, rust removal hammers, wire brushes, power wire brushes or grinding wheels. Indicated by "St".
3.3 Mechanical grinding rust removal
Rust removal on the steel surface is carried out completely with power tools, such as power sandpaper discs, pneumatic rust removal hammers, pneumatic grinding wheels, needle guns, etc. Indicated by "Ma".
3.4 ​​Local rust removal
CB 3375--91
Refers to rust removal on the local rusted parts of a part of the hull. Indicated by "P".
4 General provisions
4.1. The original state of the surface of the ship repair hull is stipulated as three original rust levels, and the surface state of the hull after rust removal is divided into three groups of eight rust removal quality levels. The original rust level and rust removal quality level of the surface are determined by text description and typical sample photos.
4.2 The original rust level and rust removal quality level are expressed by the visual appearance of the hull surface. When evaluating these levels, it should be observed directly with normal vision under good diffuse sunlight or artificial lighting conditions with equivalent illumination, without magnifying glasses or other instruments.
CB 3375-91
5 Original rust level
This standard divides the original rust state of the repair hull surface into three levels, represented by 1, I, and Z, respectively. The text description is as follows:
Level I: The paint coating of a certain area on the hull surface is basically intact, with a small amount of rust spots visible, but pitting has not yet formed: Level I: Part of the paint coating of a certain area on the hull surface is lifted or peeled off, there is loose rust, and partial pitting can be seen; Level I: The paint coating of a certain area on the hull surface is almost completely peeled off; pitting has occurred generally and large pieces of rust have formed. Typical sample photos of rust grades are shown in Chapter 8. 6 Rust removal quality grades
6.1 General
The quality grades of local rust removal on the hull surface are indicated by the codes of local rust removal and rust removal methods plus Arabic numerals, such as "PSal\", "PStl\ and "PMa\. Arabic numerals indicate the degree of removal of oxide scale, rust, original paint coating and other attachments.
6.1.2 In the retained paint There should be a transition area between the surface of the coating and the surface after rust removal.
6.1.3 Before rust removal, visible grease and dirt should be removed, and after rust removal, the surface should be free of floating dust and debris.
6.2 Rust removal quality level
When repairing a ship, local rust removal is generally performed. The firmly adhered paint coating should remain intact during the rust removal process, and the remaining rust-removed surfaces should be free of visible grease and dirt after rust removal and meet the requirements of the following table.
CB 3375--91
Rust removal quality grade requirements
Rust removal characteristics
Local light
Spray
Local more
Thorough spray
Rust removal
Quality requirements
No loosely attached
scale, rust
and paint coating and otherwwW.bzxz.Net
attachments.
No loosely attached
paint coating and
Almost no
scale, rust and other
attachments, and the residue should be
firmly attached.
CB 3375—91 Rust removal characteristics Partial contact Whitening Spraying Partial Whitening Spraying Quality requirements No frozen paint layer, no oxide scale, rust and other attachments, any residual traces should be only slight color in the form of dots or stripes No paint coating, no oxide scale, rust and other attachments, the surface should show a uniform metallic color. Manual T power T true knee rust CB 3375-91 Rust Removal Characteristics Local light manual and power tool rust removal General manual and power tool rust removal Quality requirements No loose rust and oil and paint coatings, etc. No loosely attached scales, rust and paint coatings, etc. Rust removal of manual power tools CB 3375---91 Rust removal characteristics Partial thorough manual and power tool rust removal Partial mechanical grinding Quality requirements No loosely attached scale, rust and paint coating and other attachments. Rust removal is more thorough than PSt2. The exposed surface of the substrate should have a metallic luster. No loosely attached paint coating and attachments and almost no scale and rust.
CB 3375-91
Note: ① The attachments in the table include welding slag, welding spatter, bath-soluble salts and marine organisms, etc.
② The oxide scale, rust and paint coating that can be scraped off with a gold flag putty scraper should be considered as loosely attached
③ Although the pits on the hull surface have been knocked and polished, there are still very few rust particles and paint in the pits, which are still considered to meet the requirements of PSt3 and PMa.
7 Visual assessment of the original rust level and rust removal quality level of the hull surface
7.1 The external conditions for assessment are shown in Article 4.2. 7.2 The hull surface to be inspected shall be visually compared with the corresponding photos, and the corresponding photos shall be as close to the compared surface as possible. 7.3 When assessing the original rust level, the most obvious worst level shall be taken as the assessment result; the assessment of the rust removal quality level shall be carried out immediately after the rust removal, and the level that is most consistent with the appearance of the hull surface shall be taken as the assessment result.
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