Method for restoring crack of blade of hydraulic turbine

A blade crack and repair method technology, applied in the field of metal parts repair, can solve the problems of reducing the service life of blades, material composition, complex structure, and affecting the bonding strength of welds, so as to prolong the service life, prevent weld defects, and improve welding The effect of seam bond strength

Inactive Publication Date: 2015-12-02
GUANGDONG UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Conventional repair method (i.e. filling welding) due to the difference between the filling material and the blade body material, the material composition and structure at the welding j

Method used

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  • Method for restoring crack of blade of hydraulic turbine
  • Method for restoring crack of blade of hydraulic turbine
  • Method for restoring crack of blade of hydraulic turbine

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Embodiment Construction

[0018] Such as Figure 1-4 As shown, a water turbine blade crack repair method of the present invention includes a preparation stage, a self-fluxing welding stage, a filling welding stage, and a post-processing stage.

[0019] Among them, in the above preparation stage, the following steps are performed: 1) cleaning the blade 1 to be repaired, removing oil stains and sundries on the surface of the blade 1 and in the weld seam; The maximum depth and its position; 3) Make a truncated hole 2 at each end of the crack 7 with a diameter greater than 1-2 mm of the crack width and a depth of about 3 mm greater than the crack depth; 4) Make a hole 2 with a diameter greater than the crack width 1-2 mm at the maximum crack depth 2mm, and a detection hole 5 whose depth is about 3mm greater than the crack depth; 5) Fix an ultrasonic generator 6 on the back of the blade.

[0020] When the preparatory stage is completed, the crack self-fluxing welding is carried out, and the self-fluxing we...

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Abstract

The invention discloses a method for restoring a crack of a blade of a hydraulic turbine. The method mainly comprises a preparation stage, a self-melting welding stage, a filling welding stage and an aftertreatment stage. At the preparation stage, the blade to be restored is cleaned and detected; at the self-melting welding stage, an inclined convergent laser beam with a negative defocusing amount is adopted for carrying out scanning in the extending direction of the crack, a V-shaped melting pool is formed, and molten metal liquid sinks to the bottom of the melting pool under the action of gravity, and is solidified to form a self-melting weld joint; at the filling welding stage, a material identical to a body of the blade is adopted as a welding wire for surface layer bead welding; at the aftertreatment stage, distressing tempering and blade surface finishing machining are carried out after welding is completed. In the restoring process, based on self-melting of the material of the body of the blade, the blade is filled with a few materials identical to the body of the blade, the material of the weld joint is identical to that of the blade, the material and the blade are combined well, a weld joint defect is not likely to be generated, and the combining strength of the weld joint is improved. In the self-welding welding and filling welding processes, molten metal in the melting pool is vibrated through ultrasonic waves generated by an ultrasonic generator on the back face of the blade to remove gas, and the defects of weld porosity and the like are reduced.

Description

technical field [0001] The invention relates to the technical field of repairing metal parts, in particular to a repairing process for water turbine blades. Background technique [0002] The blades of equipment such as steam turbines or water turbines are impacted by the fluid working medium during work, and fatigue cracks will occur on the surface of the blades after long-term operation. If repairs are not carried out in time, the blades will break. Blade repair often adopts methods such as surfacing welding and cladding. [0003] For example, the Chinese invention patent with the application number of 201310054557.9 discloses a repair method for aeroengine blade damage. The method performs segmented processing according to the surface size and shape characteristics of the blade to be repaired, and sets the pulse plasma heat input parameters and pulse wire feeding control of each segment. Parameters, perform plasma welding repair in sections. Another example is the Chines...

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Application Information

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IPC IPC(8): B23K26/24B23K26/211
CPCB23K26/24
Inventor 顾永玉罗红平郭钟宁张永康张永俊黄志刚
Owner GUANGDONG UNIV OF TECH
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