Manufacturing method of small-inner-diameter hollow spindle

Abstract

The invention provides a manufacturing method of a small-inner-diameter hollow spindle, which comprises the following steps: dividing a small-inner-diameter spindle into a plurality of spindle sections, respectively carrying out sectional forging, welding into an integral body, and carrying out stress-relief annealing on the small-inner-diameter spindle to finish the outer circle and the inner circle, thereby obtaining the finished product. The inner side of the welding joint of every two adjacent spindle sections is an assembly seam / spigot, and the outer side is a welding seam bevel. The welding process comprises the following two steps: carrying out bottoming and root welding in an argon arc welding mode, and filling and capping in a submerged arc welding mode. The invention implements sectional processing of the small-inner-diameter hollow spindle of a hydroelectric generating set, thereby greatly lowering the manufacturing cost, shortening the production cycle of the small-inner-diameter spindle, ensuring the welding quality of the small-inner-diameter spindle and relieving the manufacturing bottleneck of the small-inner-diameter spindle.

Description

technical field [0001] The invention relates to the mechanical processing field of spindle casting, in particular to a method for manufacturing a hollow spindle with a small inner diameter of a hydraulic generating set such as a tubular hydroelectric generating set or a tidal generating set. Background technique [0002] Due to the structure and strength requirements of the main shaft of the tubular hydroelectric generating unit or tidal generating unit, a hollow main shaft with a small inner diameter is generally used. The small inner diameter main shaft needs to bear the weight of the rotating part of the water wheel and the axial thrust of the internal water flow. At the same time, the two ends of the small inner diameter main shaft are respectively connected to the water turbine and the generator, which are related to the key components of the whole unit and transmit the torque generated by the rotation of the runner. Such as figure 1 As shown, the main structural featu...

AI Technical Summary

Problems solved by technology

However, when it is applied to the welding of such small inner diameter spindles, there are several difficulties that cannot be solved so far: 1. Since the inner diameter of the small inner diameter spindle is <600mm, welding operators cannot enter the inside of the small inner diameter spindle. Assembling, fixing and welding the root of the segmented spindle at the interface of the small inner diameter spindle; it is also difficult for non-destructive testing personnel to carry out the process and final inspection of the root of the weld

2. The submerged arc welding technology is only applicable to the flat welding position, requiring segmented spindle assembly and welding in the horizontal position

However, the shaft length of such small inner diameter spindle cannot be accurately positioned and effectively fixed when assembled in a horizontal position, and it is easy to form misaligned teeth during groove assembly, and welding defects such as lack of fusion are likely to occur during welding, and it will also affect the small inner diameter spindle after welding. The coaxiality and parallelism of the end faces

3. When submerged arc automatic welding is welding shaft products with small inner diameter, the flux will slip due to the large arc of the welding surface

The welding process cannot form effective protection, which seriously affects the welding quality

4. The wall thickness δ>300mm belongs to ultra-thick cross-section welding, and the distance between the welding pool and the operator is too far, and the operator's ability to monitor the welding process is greatly reduced

[0005] Therefore, the narrow-gap submerged arc welding segmented spindle welding technology commonly used in the hydropower industry cannot be successfully implemented in the manufacture of such spindles

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