Online surfacing welding repair method for large grinding roller sleeve

Abstract

The invention belongs to the technical field of surfacing welding methods, in particular to an online surfacing welding repair method for a large grinding roller sleeve. Compared with the prior art, the invention provides continuous, long-time heating effects for the large grinding roller sleeve by the use of pre-heating air and cooling air and effectively solves the various problems in the existing online surfacing welding repair. The weld bead is closely connected with the outer surface of the large grinding roller sleeve to be repaired and does not fall off easily. In addition, the weld bead has no crack and is resistant to wear, which conforms to the repair requirements.

Description

technical field [0001] The invention belongs to the technical field of surfacing welding methods, in particular to an online surfacing welding repair method for large grinding roller sleeves. Background technique [0002] During the operation of the large grinding roller sleeve (hereinafter referred to as the roll sleeve), its outer surface will be squeezed by the material and the grinding disc for a long time, which will inevitably cause wear. As the amount of wear increases, the output of the mill continues to decline until it needs to be stopped for maintenance. The outer surface of the roller sleeve with poor use effect or unusable can be repaired by surfacing welding. Since the roller sleeve is generally made of high hardness and high wear-resistant materials, it is not only expensive, but also returns to the factory for maintenance and replacement procedures. Complex, long cycle, high cost. [0003] In order to solve the above problems, the roller cover can be repair...

AI Technical Summary

Problems solved by technology

[0004] However, in practice, there are many problems affecting the quality, safety and progress of surfacing welding that are easily overlooked, resulting in substandard surfacing welding quality, affected progress, many safety hazards, and affecting safe production and maintenance costs.

[0005] For example, the roller sleeve has a relatively large size and thickness. When the traditional overlay welding method is used for online repair, the welding part of the roller sleeve cannot be preheated to a suitable temperature before the overlay welding point. For example, the Chinese patent with the publication number CN101433990B It discloses a method of covering the entire workpiece as a whole by covering the track heater and then preheating the track heater. The track heater can only preheat the roller sleeve between the surfacing and repairing of the roller sleeve, and the temperature of the roller sleeve can only be determined by the position. For a period of time, especially the inner surface of the roller sleeve, the temperature drops very fast, and the overall and continuous heating effect cannot be guaranteed during the surfacing of the roller sleeve, which leads to low strength or even failure of the connection between the weld bead and the roller sleeve. The weld bead formed by welding is easy to fall off, the weld bead has cracks, and the weld bead is not wear-resistant. Phenomena occur from time to time. In the slightest, rework occurs, and in severe cases, the surfacing part is broken, affecting the repair progress, and increasing the repair cost.

[0006] The working place of the mill is generally open, and the air has a great influence on the temperature of the roller sleeve, which makes it difficult to apply the patented preheating method to the online repair work of the roller sleeve

For example, due to the long repairing time of the roller sleeve, during the continuous repairing process, the welding points continue to heat the outer surface of the roller sleeve, resulting in the continuous increase of the temperature of the outer surface, and the inner and outer surfaces of the roller sleeve are formed. A large temperature difference can easily cause radial cracks or even bursts on the roller sleeve; for example, when the air temperature is low, the weld bead welded by the roller sleeve is subjected to sudden cooling, and the weld bead is prone to warping, fracture, embrittlement and other defects. As a result, the connection strength between the weld bead and the roller sleeve, and between the weld bead and the weld bead becomes low, and the surfacing repair effect is not good or even impossible to complete

[0007] The existing on-line repair method for roller sleeves has defects such as long surfacing time, poor welding bead connection stability, and inability to apply to continuous and long-term surfacing repair work, so that online repair of roller sleeves is only for some Can be used under certain circumstances, but cannot be promoted

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