This standard specifies the basic requirements, cleaning process and acceptance requirements for chemical cleaning of steel pipes, copper pipes and aluminum pipes. This standard is applicable to chemical cleaning of steel pipes, copper pipes and aluminum pipes. CB/T 3760-1996 Chemical cleaning of steel pipes, copper pipes and aluminum pipes CB/T3760-1996 Standard download decompression password: www.bzxz.net

Shipbuilding Industry Standard of the People's Republic of China
CB/T3760-1996
Chemical Cleaning of Steel, Copper and Aluminum Pipes
Published on September 3, 1996
Implemented on April 1, 1997
CB/T3760-1996
This standard is a revision of the two standards CB/Z98-68 "Chemical Cleaning of Steel, Copper and Aluminum Pipes" and CZ40-61 "Chemical Cleaning of High-Pressure Copper Pipes", and adds the basic requirements and process flow of chemical cleaning. From the date of entry into force, this standard replaces CB/Z98-68 and CZ40-61 at the same time. Appendix A of this standard is a reminder appendix.
This standard was proposed by the Shipbuilding Technology Sub-Technical Committee of the National Technical Committee for Standardization of Marine Ships. This standard is under the jurisdiction of the 611 Institute of China State Shipbuilding Corporation. The drafting unit of this standard: Hudong Shipyard. The main drafters of this standard are: Zhang Jinfang, Yang Jun, Tang Yuming. 1 Scope
Ship Industry Standard of the People's Republic of China
Chemical Cleaning of Steel Pipes, Copper Pipes and Aluminum Pipes
CB/T3760-1996
Classification Number: U06
Replacer%/%-68
This standard specifies the basic requirements, cleaning process and acceptance requirements for chemical cleaning of steel pipes, copper pipes and aluminum pipes. This standard is applicable to the chemical cleaning of steel pipes, copper pipes and aluminum pipes. 2 Basic Requirements
2.1 General Requirements for Chemical Cleaning:
a) Remove grease, protective layer and other attachments on the surface of the pipe; b) Remove oxide scale and severe rust on the surface of the pipe; c) Remove dirt remaining on the surface of the pipe. 2.2 The chemical cleaning solution must be tested regularly and its chemical composition must be adjusted in time according to the test data. 2.3 The rinse tank for clean water rinsing should have an overflow port to remove grease on the water surface and have sufficient water flow. 2.4 The same pickling tank cannot be used for steel pipes, copper pipes, and aluminum pipes. 2.5 In addition to the formula of chemical cleaning solution according to Appendix A (the suggested appendix), other formulas with less environmental pollution can also be used. 2.6 The disposal of chemical cleaning solutions that can no longer be used must comply with environmental protection regulations. 3 Chemical cleaning of steel pipes and copper pipes
3.1 Chemical cleaning process
Preparation work→Chemical degreasing→Hot water rinsing+Acid cleaning→Clean water rinsing→+Passivation→Hot water rinsing→+Drying→Maintenance. 3.2 Preparation work
3.2.1 For pipes with oil seals on the surface, scrub them with diesel (or water-based detergent) before chemical degreasing. Pipes with severe oil stains or pipes coated with anti-rust asphalt or resin can be treated by other methods. 3.2.2 Pipes with severe dirt can be removed by mechanical methods. 3.3 Chemical degreasing
3.3.1 Chemical degreasing should be done by soaking in a tank. 3.3.2 When soaking in the tank, pay attention to the direction of the cleaning parts to avoid air in the pipe. 3.3.3 During the soaking process, the pipe should be turned over to continuously change the solution in the inner cavity. 3.3.4 Chemical degreasing until the surface of the pipe is completely wetted by water. 3.4 Hot water rinsing
Soak the pipe in a water tank with a water temperature of about 80 for 3 to 5 minutes, and the water should flow and be renewed. 3.5 Pickling
3.5.1 Pickling should be done by soaking in a tank.
3.5.2 When soaking in the tank, the direction of the cleaning parts should be in accordance with the provisions of 3.3.2. 3.5.3 The soaking process should be carried out in accordance with the provisions of 3.3.3. 3.5.4 When the rust or oxide scale on the surface of the steel pipe is loose and can be easily removed by rubbing lightly, the pickling of the steel pipe is completed. Approved by China State Shipbuilding Corporation on September 3, 1996, and implemented on April 1, 1997
CB/T3760-1996
3.5.5 When the surface oxide scale of the copper tube is completely removed and it shows red copper color, the copper tube pickling is finished. 3.6 Clean water flushing
The water flow should have appropriate impact force. It is advisable to use a mixed flow of compressed air and water to spray the surface of the tube to remove the surface dirt after pickling, and then put it into the water rinse tank for rinsing.
3.7 Passivation
3.7.1 Passivation should be carried out by soaking in the tank.
3.7.2 When soaking in the tank, the direction of the cleaning parts shall be in accordance with the provisions of 3.3.2. 3.7.3 The soaking process shall be carried out in accordance with the provisions of 3.3.3. 3.8 Hot water flushing
3.8.1 Rinse the tube with hot water at a temperature of about 80℃ until it is clean. 3.8.2 After the pipe is passivated, if it does not affect the subsequent process or the use of the pipe, the hot water flushing can be omitted. 3.9 Drying
3.9.1 Blow the pipe dry with clean compressed air. 3.9.2 For high-pressure pipeline copper pipes with a pressure of ≤24.5MPa, the surface of the pipe must be blown completely dry with clean hot air with a gauge pressure of p≤50Pa and a temperature of 80~150℃. 3.10 Maintenance
3.10.1 After the chemically cleaned pipe passes the inspection, in order to ensure the cleaning quality, the pipe surface should be coated with the prescribed protective layer in time. 3.10.2 The pipe ends and branch pipe openings should be sealed with appropriate covers, plates and other materials, and stored in a clean and dry place. 3.11 Others
After the steel pipe is treated by pickling and phosphating in one step, the three processes of water flushing, passivation and hot water flushing can be omitted. 4 Chemical cleaning of aluminum tubes
4.1 Chemical cleaning process
Preparation-→ pickling or alkali cleaning for oil removal→ rinse with clean water→ polishing→ rinse with clean water→ drying→ maintenance4.2 Preparatory work
Preparatory work before chemical cleaning shall be carried out in accordance with the provisions of 3.2.1 and 3.2.2. 4.3 Pickling or alkali cleaning for oil removal
4.3.1 Pickling or alkali cleaning shall be carried out by immersion in a tank, and the process shall be carried out in accordance with the provisions of 3.3.2 and 3.3.3. 4.3.2 The immersion time of pickling or alkali cleaning shall be such that the surface dirt is completely removed without excessive corrosion. 4.4 Rinse with clean water
Rinse the tube with clean water to remove the surface dirt after pickling or alkali cleaning. 4.5 Polishing
Use the method of immersion in the tank until the surface is silvery white. 4.6 Rinse with clean water
Rinse the pipe with clean water to make the pH value of the pipe surface neutral. 4.7 Drying
Drying shall be carried out in accordance with the provisions of 3.9.1.
4.8 Maintenance
Maintenance shall be carried out in accordance with the provisions of 3.10.
5 Acceptance requirements
5.1 After chemical cleaning, the steel pipe shall be grayish white. After chemical cleaning, the copper pipe shall be red copper (local dark color and water marks are allowed). After chemical cleaning, the aluminum pipe shall be silvery white. 2
CB/T3760-1996
5.2 Grease, dirt, oxide scale, rust, loose materials, sand and garbage are not allowed to exist on the pipe surface. 5.3 The outer surface of the pipe shall be fully inspected. For the inspection of the inner surface of the pipe, 1 to 3 pipes can be selected from each batch, and white cloth can be passed through the inside of the pipe to check whether there is oxide scale, garbage, etc. If one piece fails, double sampling should be carried out for re-inspection. If one piece still fails, all pipes should be inspected.
5.4 The pH value of the pipe surface after chemical cleaning can be tested with pH test paper. The pH value of steel pipes should be within the range of 7 to 10. Copper and aluminum pipes should be neutral.
5.5 Pipes that fail the inspection must be reprocessed. No.
Solvent name
Sodium hydroxide
Sodium carbonate
Sodium silicate
Sodium hydroxide
Trisodium phosphate
Sodium silicate
Sodium carbonate
Sodium hydroxide
Corrosion inhibitor, etc.
Corrosion inhibitor, etc.
Corrosion inhibitor, etc.
Sodium carbonate
Sodium nitrite
Corrosion inhibitor, etc.
CB/T3760—1996
Appendix A
(Suggested appendix)
Recommended chemical cleaning solution formula
Solution composition and concentration
Chemical molecular formula
Na,Si,
NaSiO ,
Concentration+g/L
80~120
150~200bZxz.net
200~250
100~150| |tt||100150
50~100
150200
Solution temperature
around 90
around 90| |tt||Around 90
For chemical degreasing of steel and copper tubes
For chemical degreasing of copper tubes
For degreasing and alkali cleaning of aluminum tubes
For pickling of steel tubes
For pickling of steel and copper tubes
For pickling of aluminum tubes
For polishing of copper tubes
For passivation of steel tubes
For pickling of steel tubes
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.