Process for parkerising internal surface of long thin steel tube with manganese phosphate

Abstract

The invention relates to a process for parkerising a steel tube with manganese phosphate, in particular to a process for parkerising the internal surface of a long thin steel tube with manganese phosphate, which comprises the following steps: 1, cleaning with alkali; 2, cleaning with high-pressure water twice; 3, derusting with 5% hydrochloric acid; 4, cleaning with high-pressure water; 5, carrying out surface conditioning in a Bondfine PM solution for 0.5-1 minute; 6, carrying out manganese phosphate film treatment in a Bondeline 448 solution; 7, cleaning with high-pressure water twice; 8, carrying out antirust oil coating and seal treatment on the surface; and 9, heating and drying the surface. The invention thoroughly solves the technical problem that the internal wall of a long thin tube can not be subjected to manganese phosphate parkerising treatment in the field, and ensures that the parkerising quality of the internal wall is the same as that of the external wall, thereby having wide use value.

Description

Technical field [0001] The invention relates to a manganese phosphate phosphating process for steel pipes, in particular to a manganese phosphate phosphating process for slender seamless carbon steel pipes. Background technique [0002] After the steel parts are treated in the manganese-containing phosphoric acid solution, a layer of manganese salt phosphating film that is insoluble in water will be formed on the surface. The film layer is mainly composed of manganese phosphate and acid manganese iron phosphate. This phosphating film is fine and compact, excellent in adhesion, friction resistance, high corrosion resistance and hardly soluble in water crystal protective film, which can improve the anti-adhesion and wear resistance of the workpiece, and prevent seizure or scratches. And because of the porous storage lubricating oil characteristics of the phosphating film, it has better wear resistance after being immersed in oil. [0003] The quality of manganese phosphate phosphati...

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Problems solved by technology

[0003] The quality of manganese phosphoric acid phosphating depends on the uniformity of contact between the phosphating solution and the phosphating part and the soaking time. For general workpieces and products soaked in the phosphating solution, it is easy to control the soaking time and the uniformity of surface contact. However, for steel pipe fittings, especially slender pipe fittings, it is difficult for the manganese phosphoric acid phosphating solution to enter the inner wall of the steel pipe evenly and smoothly, and it is difficult to ensure a relatively consistent phosphating time. It takes enough time, but the phosphating solution has not yet entered and reached the middle of the part, so it is difficult to perform manganese phosphoric acid phosphating treatment on the inner wall of the slender steel pipe, or the quality of the treatment is very poor

[0004] In the prior art, for manganese phosphoric acid phosphating treatment of seamless carbon steel pipes with a length of 6000 mm and an inner hole of 8 mm, a pressure gun is generally used to align the pipe mouth with forced pressure into the phosphating solution. However, because the inner diameter of the steel pipe is relatively small, it is often When spraying, the phosphating solution will be reflected from the tube, and cannot evenly enter the entire tube to complete the phosphating, and the quality of phosphating is also very poor.

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