The function of cleaning is to clean the remaining acidic substances and other sundries on the surface of the square pipe, and good cleaning effect can be obtained through passivation treatment. To consider the temperature of hot water for cleaning and other matters, let's talk about it briefly.
The cold water washing tank should always be kept full flow, and the high-pressure water should be continuously washed. The water pressure should be kept above 0.5MPa for the production and processing of cold drawn special-shaped steel pipes. Under the above conditions, the mass concentration of acid in cold water shall not exceed 0.1g/l, otherwise the cold drawn seamless pipe after pickling is easy to rust. Test the mass concentration of acid in cold water every day and at night. The hot water temperature of the hot water tank should be above 95 ℃, and there should be no acid in the hot water to prevent the square pipe from rusting.
A pair of squeeze rubber rollers at the outlet of the hot water tank shall be pressed tightly to ensure the moisture on the surface of the square tube. In the continuous pickling unit, the square tube is oiled after pickling, so that the square tube will not rust during the storage period (about 10 days) before rolling. Passivation is to form a passivation film on the surface of the pickled square tube, improve the ability to resist environmental corrosion, and generally ensure that the square tube will not rust within 2-3 days.
In addition, the reason why square tubes can be loved and widely used is because square tubes have many advantages. It is these advantages that make square tubes become "regular customers" in our life. In the past, the materials used were very common and easy to rust, and the use time was often not very long, but now the square tube used, after anti-corrosion treatment, this square tube will not rust easily. It will take a long time to use.
The heavy strength of square tube is slightly higher than that of other materials, with little quenching and no tempering brittleness. Cold deformation has high plasticity. It is generally used for bending, calendering, bending and hammer arch processing. Electric arc welding and contact welding have good welding performance. During gas welding, cracks are easy to occur on parts with small thickness, strict shape requirements or complex shape. The machinability of cold drawing or normalizing state is better than that of annealing state. It is generally used for manufacturing with low stress and high toughness requirements.
Jinan square tube is suitable for engineering, coal mining and textile production. Of course, every advantage of square tube will be used in the field. Just as square tube is very light, it is widely used in manufacturing parts, such as the frame of bicycle. The advantages of square tube are far more than these. It is these advantages that make square tube can be used in a large number of ways, and also provide a lot of convenience to our life. At the same time, square tube manufacturers have also received rich benefits.
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