Composite welding preparation method for babbitt metal on surface of curved surface bearing bush

Abstract

The invention discloses a composite welding preparation method for a babbitt metal on the surface of a curved surface bearing bush. The preparation method comprises the following steps of 1) processing a curved surface bearing bush blank; 2) integrally preheating the curved surface bearing bush; 3) cleaning the surface before welding; 4) welding a priming coat of the babbitt metal along a preset welding path by adopting a right welding method in a pulse welding mode; and 5) welding babbitt metals in a second layer and a third layer along a preset welding path by adopting a left welding methodin a cold metal transitional mode. The method disclosed by the invention can improve the welding forming quality of the babbitt metal on the curved surface bearing bush and solves the problem that thebabbitt metal at the edge of the bearing bush collapses, the bonding strength is improved, the service life is prolonged, the repair rate of a product is reduced, and the material cost is saved.

Description

Technical field: [0001] The invention relates to the field of hydroelectric generator product manufacturing, in particular to a preparation method for babbitt alloy compound welding on the surface of a curved bearing bush of a large hydroelectric generator. Background technique: [0002] The bearing bush is an important component of the bearing, which is used to support the shaft and the parts on the shaft, ensure the rotation accuracy of the shaft, and reduce the friction between the shaft and the parts on the shaft. In order to improve the wear resistance of the bearing bush, Babbitt alloy with a thickness of 3 mm to 6 mm is usually prepared on its surface. [0003] The traditional production process of the Babbitt alloy layer on the surface of the bearing bush is mainly static casting and centrifugal casting. Due to the low melting point of the Babbitt alloy material and the characteristics of different densities of the three intermetallic compounds during crystallization...

AI Technical Summary

Problems solved by technology

[0003] The traditional production process of the Babbitt alloy layer on the surface of the bearing bush is mainly static casting and centrifugal casting. Due to the low melting point of the Babbitt alloy material and the characteristics of different densities of the three intermetallic compounds during crystallization, centrifugal casting or static casting is used to obtain The babbitt alloy layer has problems such as composition segregation, low bonding strength, and many surface defects. In addition, the casting process is cumbersome, the degree of automation is extremely low, and the product quality is unstable.

[0004] In recent years, the industry has developed the process of using CMT cold metal transfer technology to realize the welding of babbitt alloy on the surface of the bearing bush, which basically solved the problems of composition segregation and surface defects, but based on the characteristics of the extremely low heat input of CMT cold metal transfer technology , the metallurgical reaction between the prepared babbitt alloy and the base metal of the bearing pad is usually very little, which leads to the bonding strength of the babbitt alloy is not too high. The bonding strength of the matrix is ​​20MPa~30MPa, which will greatly affect the service life of the product; in addition, due to the low melting point of Babbitt alloy (solid phase point temperature is 240 °C, liquid phase point temperature is 370 °C), the welding process is extremely Easy to flow, when using automatic welding equipment to surfacing Babbitt alloy according to the zigzag path, the characteristics of the obtained Babbitt alloy will be thick in the middle and thin at the edge. Figure 5 Shown is a schematic diagram of the cross-section of the Babbitt alloy on the surface of the bearing bush obtained by the traditional zigzag welding track. The flow of the Babbitt alloy during the welding process causes a large range of collapse at the edge position. The collapse of the Babbitt alloy directly causes the waste of welding materials, and the existence of the collapse directly causes the thickness of the Babbitt alloy in this area to fail to meet the product design requirements, requiring manual repair welding

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