For
steel pipes that require chemical cleaning (pickling), the cleaning scope and quality requirements shall meet the requirements of the design documents. If there are special cleaning requirements for the inner wall of steel pipelines, such as hydraulic and lubricating oil steel pipelines, chemical cleaning can be used for de-rusting. The implementation points are as follows:
(1) When performing chemical cleaning of steel pipelines, unrelated equipment, and steel pipelines should be isolated.
(2) The formulation of the chemical cleaning solution should be used after being tested and identified.
(3) Pickling and passivation of steel pipelines should be carried out in the order of degreasing, pickling, water washing, passivation, water washing, and drying with oil-free compressed air. When pickling is carried out in a circulation mode, the steel piping system shall be passed the air leak test or hydraulic leak test in advance.
(4) The steel pipes after chemical cleaning shall be inspected visually. The metal luster on the inner wall is qualified.
(5) For steel pipes that cannot be put into operation in time and pass the chemical cleaning, protective measures should be taken to seal or fill them with nitrogen.
