Repair method of airplane hydraulic system aluminum alloy piston rod wear-resisting layer damage

Abstract

The invention relates to a repair method of airplane hydraulic system aluminum alloy piston rod wear-resisting layer damage. The repair method comprises the following specific steps: removing an old film layer on an aluminum alloy piston rod through an alkali corrosion method; checking whether corrosion, gouges, scratches, abrasion and other damage exist on the surface of an aluminum alloy pistonrod base body or not in a visual mode, and eliminating the existing damage; and measuring the size of the excircle surface of the piston rod, calculating the thickness size, and increasing the thickness of a spraying coating by 1-2mm on the thickness size. The repair method has the advantages that on the basis of an existing repair method, the repair technology and process are optimized, a cold spraying additive manufacturing working procedure is added, the size recovery of the piston rod is achieved through cold additive forming operation, hard anodizing of the coating is carried out on the basis, then a film layer is sealed through a hole sealing technology, and the sealing performance of the film layer is further improved. The problem that the size of the piston rod is reduced after theold film layer is removed through alkali corrosion and hard anodizing is conducted again in the traditional repair process is solved.

Description

technical field [0001] The invention relates to the technical field of aircraft component repair, in particular to a method for repairing damage to the wear-resistant layer of an aluminum alloy piston rod in an aircraft hydraulic system. Background technique [0002] The piston rod is an important force transmission component in the aircraft hydraulic system. Due to the frequent reciprocating motion and load bearing, in order to improve the wear resistance of the aluminum alloy piston rod, the hard anodizing process is often used in the process of parts processing. Through The electrochemical reaction forms a dense, wear-resistant gray-black oxide protective film on the surface of the part, with a thickness of about 50-60 μm, which can significantly improve the wear resistance of the part. As the use time of the parts increases, the anodized layer will suffer from wear, scratches and other failures, resulting in excessive fit clearance, reduced sealing performance, oil leaka...

AI Technical Summary

Problems solved by technology

As the use time of parts increases, the anodized layer will suffer from wear, scratches and other faults, resulting in excessive fit clearance, reduced sealing performance, oil leakage and other problems, affecting the reliability of use, and the piston rod needs to be repaired

[0003] The common repair methods for the above faults are: remove the old hard anodized film layer → eliminate the substrate damage (if necessary, if and only if the substrate is still damaged after the film layer is removed) → re-hard anodize, but the above process has the following Problem: The old hard anodized film is mainly removed by alkali corrosion, and part of the substrate size will be lost during the removal process, while the formation of a new anodized film mainly depends on the electrochemical reaction between the substrate and the bath to form a new film. Part of the size will also be lost when the matrix participates in the reaction, that is, when the matrix is ​​not damaged, the re-anodization will reduce the size of the piston rod by about 30 μm. If the matrix of the piston rod is damaged, the size of the piston rod will be will be smaller

After such re-anodization for 1-2 times, the piston rod will be completely irreparable due to the size of the piston rod being too small and the fit clearance being out of tolerance.

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