Method for repairing microcrack tip on stainless steel surface by means of nano-particles

Abstract

The invention provides a method for repairing a microcrack tip on a stainless steel surface by means of nano-particles. The method is suitable for stainless steel with microcracks on the surface. The method comprises the steps that the to-be-repaired microcrack tip on the stainless steel surface is treated; composite powder containing the nano-particles is arranged on the microcrack tip in advance; the composite powder and a part of a matrix are fused by means of lasers; the repaired microcrack tip region is finished; and the fracture property of the stainless steel matrix obtained after repairing is detected, and the microstructure of the section of a repair layer is observed. The repairing method is high in flexibility, and repairing can be carried out many times; and meanwhile, the problems of large deformation, a large heat affected zone and the like in a conventional method are avoided in the repairing method. According to the repairing method, the microcrack tip is closed again, the matrix and the composite powder arranged on the microcrack tip in advance are in metallurgical bonding, and the defects of cracks, pores and the like do not exist in the bonding region; grains of the repair layer of the microcrack tip are refined, and the structural compactness is improved; and in addition, the fracture property generated after repairing is remarkably improved.

Description

technical field [0001] The invention belongs to the technical field of crack repair, and relates to a method for repairing the tips of tiny cracks on the surface of stainless steel by using nanoparticles. The method is suitable for stainless steel with tiny cracks on the surface. Background technique [0002] Due to its good strength and superior corrosion resistance, stainless steel is widely used in automotive, energy, aerospace and other fields. The service workpiece made of stainless steel will produce microscopic defects under the influence of cyclic loading and working stress, and the microscopic defects will slowly expand into macroscopic cracks. In order to ensure the safety of the workpieces in service, we have to reluctantly discard the workpieces containing tiny cracks. Equally, because stainless steel can produce damage or scratch on its surface in the process of processing, transportation, if can not carry out good recovery to workpiece, whole workpiece will be...

AI Technical Summary

Problems solved by technology

Traditional repair methods, such as argon arc welding, plasma spraying, plasma arc welding, and tungsten inert gas shielded welding, are simple in process but require a large amount of heat input during the repair process, and thermal cracks are prone to appear in the heat-affected zone, and welding is easy to deform , it is easy to cause problems such as falling off and cracking during use, and it is easy to cause shrinkage and deformation during the repair process, so the application of these methods has great limitations

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