(1) Defatting - using degreasing agent to remove the oil attached to the pipe;

(2) Washing - removing dirt from the pipe with clean water;

(3) Removing rust - removing rust spots on the pipe wall, rolling iron filings, etc., in the pickling solution;

(4) Washing with water and high-pressure water - flushing the attachment produced in the above operation with clean water and flushing the inside of the tube with high-pressure water;

(5) Neutralization - neutralizing the residual acid on the pipe with lye;

(6) Drying-in order to dry effectively, the pipe should be immersed in hot water or steam dried, and the pipe should be dried thoroughly;

(7) Antirust;

(8) Inspection - inspection of the pipe after pickling and whether it is cleaned or not;

(9) Packaging and custody - seal the opening of the pipe with plastic or plastic tape immediately after pickling to prevent foreign bodies, moisture, etc., from invading.

Matters needing attention in pickling

The main results are as follows:

(1) The welding operation of the pipe has been completed before pickling;

(2) Then disassembling, transporting and pickling, be careful not to hurt the pipeline, thread and sealing surface, and block the seal with tape or plastic pipe;

(3) The welding slag, spatter and varnish on the pipe should be cleaned before pickling;

(4) The parts of each thread shall be protected by acid-resistant materials such as plastic tape and rubber belt, or coated with dry oil on the thread after degreasing and washing, and then rust in the acid solution to prevent acid erosion;

(5) Then pickling, be careful not to make the matching mark of the pipe disappear or blur.