So called pickling is using hydrofluoric acid and nitric acid solution to wash steel surface oxide generated after heat-treated. Used in the solution composition and ratio values: HF (3-8%), HNO3 (10-15%), H2O (the remaining amount) when processing solution temperature at 40-60 °C.

Steel pipe pickling procedure:
Clean up debris in oil spill → Loaded baskets → Chemical degreasing → Hot water cleaning  → Cold water Cleaning  →  Chemical rust → high pressure hair water purge →  The flow of water to wash  → Hot water cleaning → Blow-dry → test

The pickling process should pay attention to the following points:
The first point :the acceptance of incoming listed, specifications, quantity and straightening cut quality unqualified acceptance of pause the pickling and timely notice of the quality control department or workshop.

The second point:The first is to add acid in accordance with the ratio value of the shop floor control, added acid should be evenly distributed in the pickling tank, rather than adding in one part of the acid tank; then control the size of the amount of steam, in order to control the temperature of the acid steels generally control the temperature of the acid to slightly steaming prevail (about 60 degrees), and should not control the temperature is too high or feeling of boiling acid; remaining is to organize the process of site steel pipe card, to distinguish between the different frame number, Because of the presence of different kinds of steel pickling time difference.

The third point :the pickling process control, and also the most important step. Different products steel pipes and finished steel pickling and degreasing. Which, lifting products steel pipes can be directly used nylon rope to the pickling tank, hanging the fashionable steel pipe should tail high head low, so that the acid can successfully enter the pipe bore; finished steel pipe hanging into the acid bath pickling, at appropriate intervals time lifting steel pipe back into the acid tank, to be the oxidation of the surface of the steel pipe inside and outside Picchi this off to remove the steel pipe, gradually branched substantially flush with high-pressure water jets to wash pipe bore, then steel pipe into the hanging folders in the acid soak appropriate time steel pipes hanging out the acid tank should be soaked for 10 minutes in the sink and then gradually branched rinse the inside and outside surfaces. To oil pipe should go sump off of the surface oil and lubrication lime soak in the sink for 10 minutes and then rinse the inner hole-by-branch flush; rolling the finished products to the oil pipe in the sink to soak for a period of time sure the steel pipe has cooled completely, the steel pipe into the acid bath for half a minute, and then into the sink and flush-by-branch.

The fourth point:the pickling process after the inspection work. Finished pickling steel pipe test focused primarily oxide cleanliness of the inner and outer surfaces of the steel pipe, especially in the cleanliness of the inner bore, the best use yarn DON by formula inspection, the sampling amount should be not less than 10%. Followed by acid blot testing the steel surface and steel pipe color inspection failure should be re-pickling; away oil the surface of the steel pipe should be no oil spill, particular attention should be no residual acid outflow pipe ends.