Precautions for pickling of seamless steel pipes

Pickling of seamless steel pipes (SMLS pipe) is an important process for treating the surface of steel pipes and removing impurities such as oxides and rust. When pickling seamless steel pipes, the following matters need to be noted:

1. Preliminary preparation

Wearing labor protection supplies: Before pickling seamless steel pipes, workers must wear labor protection supplies, such as acid and alkali resistant gloves, goggles, protective clothing, etc., to prevent acid from splashing on the body and causing injury.

Check the working environment: Conduct a detailed inspection of the working environment on site, mainly to check whether the slings of the seamless steel pipe are intact, and only after confirmation can the operation be carried out.

2. Pickling operation

Concentration and temperature of pickling agent:
The concentration and temperature of pickling agent will directly affect the pickling effect. The pickling agent generally used is hydrochloric acid solution, and the concentration is usually between 10% and 20%. The specific concentration needs to be determined according to the material and surface condition of the steel pipe.

Temperature is also an important factor affecting the pickling effect. It usually needs to be carried out within an appropriate temperature range to avoid being too high or too low.

Pickling time:
The pickling time should be determined according to the material, thickness and surface contamination of the steel pipe. Generally speaking, the pickling time should not be too long to avoid excessive corrosion of the steel pipe. The time is usually controlled between 5 and 15 minutes, and the specific time can be adjusted according to the actual situation.

Vibration and tilting:
During the pickling process, the seamless steel pipe needs to be vibrated frequently to ensure that the acid can evenly cover the surface of the steel pipe.
When the pipe is lowered into the acid tank, the seamless steel pipe should be tilted to prevent the hydrochloric acid from accidentally injuring people.

Steel pipe weight control:
For the pickled seamless steel pipe, its weight should be controlled within a certain range, usually recommended between 2 and 5 tons, to ensure the consistency and safety of the pickling effect.

3. Subsequent treatment

Full cleaning and drying:
After pickling, the seamless steel pipe needs to be fully cleaned to remove residual acid and impurities. After cleaning, it is also necessary to blow dry to avoid secondary corrosion of the steel pipe by residual moisture.

Passivation treatment:
In order to improve the corrosion resistance of seamless steel pipes, passivation treatment can be carried out after pickling. Passivation is achieved by forming a dense oxide film on the surface of the steel pipe. The passivating agent usually used is chromic acid solution, etc.

4. Safety protection and environmental protection

Safety protection:
During the entire pickling process, it is necessary to strictly abide by the safety operating procedures to ensure the personal safety of the staff. At the same time, the pickling equipment should be inspected and maintained regularly to prevent accidents caused by equipment failure.

Environmental protection treatment:
Chemical wastes such as pickling liquid should be treated and recycled in accordance with environmental protection requirements to avoid pollution to the environment.

In summary, the matters that need to be paid attention to in the pickling of seamless steel pipes cover multiple aspects such as preliminary preparation, pickling operation, subsequent treatment, safety protection and environmental protection. Only by strictly observing these precautions can the quality and safety of pickling of seamless steel pipes be ensured.

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