A method for anti-corrosion treatment of tail rudder connecting rod thread

Abstract

The invention belongs to the field of static powder coating preservative technology in marine environment, and relates to a preservative treatment method of tail vane connecting rod threads. The method comprises the steps of selecting tail vane connecting rod external threads of which the section is of stage shaped structure or rectangular tooth shaped structure, chamfering the square edge of the connecting rod threads, cleaning and drying the to-be-painted surface, grounding the connecting rod threads, shielding the first threads by a transparent adhesive tape, statically spraying power to the connecting rod threads, heating and roasting the connecting rod threads in an oven, then cooling, finishing thermal sintering and curing, turning to remove a redundant PEEK (poly ether ether ketone) layer, and performing secondary static spraying powdering, thermal sintering and curing on the first threads of the connecting rod threads, thus realizing the insulating type preservative treatment of the whole connecting rod threads. The whole technical principle is reliable, the operation steps are simple and easy to control, the used equipment is available, the preservative effect of the sprayed powder is good, the service life is long, and the preservative operation is environment-friendly.

Description

Technical field: [0001] The invention belongs to the technical field of electrostatic powder coating anticorrosion in marine environment, and relates to a compound preparation process of electrostatic powder spraying and thermal sintering curing for ship rudder propeller connecting rod thread insulation anticorrosion polyether ether ketone (PEEK) coating, especially It is an anti-corrosion treatment method for the thread of the rudder connecting rod. Background technique: [0002] The existing insulation technology is generally achieved by reducing the size of the connecting thread and adding insulators, and some are realized by insulating sleeves. These existing methods will cause the strength of the connecting thread to fail to meet the requirements, or due to the installation of the insulating sleeve The process is complicated, and there is a large hidden danger of conduction; and the method of realizing thread insulation by spraying high-resistivity materials has not yet...

AI Technical Summary

Problems solved by technology

[0002] The existing insulation technology is generally achieved by reducing the size of the connecting thread and adding insulators, and some are realized by insulating sleeves. These existing methods will cause the strength of the connecting thread to fail to meet the requirements, or due to the installation of the insulating sleeve The process is complicated, and there is a large potential for conduction; and the method of thread insulation by spraying high-resistivity materials has not yet been reported.

Chinese invention patent CN201310602468.3 discloses an electrostatic spraying + thermal sintering curing method of PEEK coating, but there is no technical feature on how to achieve uniform coating on the complex shape surface; Chinese invention patent CN201210187043.6 discloses a The method of preparing PEEK coating by electrostatic spraying + thermal sintering curing on the thread surface of the collar; these two patent technologies only describe how to spray and cure and the curing process, but do not involve how to uniformly obtain PEEK insulating coating on the surface of the thread; at the same time, electrostatic Due to the high porosity of spray coating, in actual use, if the coating is thin, there will be a high defective rate

In addition, the above-mentioned technology is aimed at tapered threads, and there are differences between the thread of the stern rudder connecting rod and the thread of the EMWD sub-section. Firstly, the thread of the connecting rod is a barrel thread, while the thread of the EMWD sub-section is It is a tapered thread, and the tolerance requirements of the tapered thread are relatively small. When there is a certain tolerance that cannot be matched, under the premise of meeting the mechanical performance requirements, a gasket can be applied to achieve a gapless fit; even so, on the thread surface The prepared coating also often has unevenness, which leads to poor fit of the thread, and the possibility of redoing after firing is also very high; for cylindrical bolts, it is impossible to meet the fit requirements by applying gaskets, because as long as it is uneven, it will appear. The problem of not screwing in or not tightening; therefore, designing a process method of anti-corrosion coating for the thread of the tail rudder connecting rod is of great application value

[0003] At present, the materials used for the connecting rod thread and the stern rudder of the ship are different. These materials have a large potential sequence difference in the seawater medium, and severe galvanic corrosion will occur; at the same time, the connecting rod thread and the butt thread are not Water-tight, there are tiny gaps during movement, which are enough to cause serious crevice corrosion. Therefore, corrosion and pull-off of connecting rods occur from time to time, and no effective corrosion protection method for connecting rods has been found yet

In view of the serious corrosion problem of the thread at the connecting rod of the stern rudder, an insulating and anti-corrosion coating is applied to the surface of the connecting rod thread to electrically isolate the butt joint of the connecting rod and eliminate the galvanic couple caused by the excessive potential difference between the two metals. Corrosion; at the same time, the coating has the effect of isolating and blocking the seawater medium, preventing the occurrence of crevice corrosion in the tiny gaps between the connecting rods, so as to solve the phenomenon of pull-off of the stern rudder connecting rod thread well site has not yet been published

There are many forms of special corrosion on special parts of ships, which will cause serious impacts, but usually there is no effective solution

For example, the connection of dissimilar metals (copper, brass, stainless steel, etc.) in the joints of seawater pipeline systems is relatively common. Due to the large potential difference between different materials, serious galvanic corrosion problems will occur, which will affect the reliability of pipeline operation and limit the The use of materials; galvanic corrosion can be effectively reduced by isolating the electrical connection between dissimilar metals. The insulation technology currently used is mainly insulating gaskets. Because ordinary rubber is easy to age and has poor mechanical properties, the service life and reliability are affected. There are great restrictions. Improper installation of gaskets will form tiny gaps and cause more serious crevice corrosion. Therefore, an alternative insulating sleeve technology is sought to avoid the complicated process of installing insulating devices and improve equipment installation efficiency and safety. Sexual craftsmanship is necessary

At the same time, seek an insulating coating preparation that can be used to measure insulating pup joints while drilling, and replace the current ceramic coating. The resistivity of the ceramic coating is low. When contacting a large area, the insulation resistance is often too small. material whose bulk resistivity is 10 15 Ω.m or more, can work at a high temperature of 260°C for a long time, and excellent materials with an insulation resistance of 100MΩ or more also have a wide range of application backgrounds

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