Automatic filler wire welding process of electric heating elements of voltage stabilizer of nuclear power plant

Abstract

The invention belongs to the technical field of field replacement of electric heating elements of a voltage stabilizer of a nuclear power plant or equipment manufacturing and mounting, and particularly relates to a field replacement full-set process of the electric heating elements of the voltage stabilizer of the nuclear power plant. The process aims to reduce the welding heat input and eliminateheat crack risk; the risk that weld joint is not welded thoroughly or the root of the weld joint is not fused is eliminated, and the good forming of the inner and outer surfaces of the weld joint isensured standard welding wire materials replace specially-made ferrite filling rings to serve as welding materials, the import dependence of foreign materials is free, and the cost is reduced greatly;and an automatic filler wire pulse tungsten electrode welding process and a matched auxiliary process achieving the welding process achieve the field replacement of the electric heating elements withhigh quality. The process achieves the field replacement of fourteen electric heating elements successfully for four times at 1# and 2% machines at Fangjia Shan and the 1# machine at the Qin Second Plant, all replacement achieves one-time operation and one-time acceptance, and the process reliability is successfully verified.

Description

technical field [0001] The invention belongs to the technical field of on-site replacement or equipment manufacturing and installation of an electric heating element of a voltage stabilizer in a nuclear power plant, and in particular relates to an automatic wire-filling welding process for an electric heating element of a voltage stabilizer in a nuclear power plant. Background technique [0002] The voltage stabilizer is an important device for the pressure boundary of the primary circuit of the nuclear power plant, and it mainly plays the role of stabilizing the pressure of the primary circuit. The electric heating element is the main functional element of the voltage stabilizer. The electric heating element is inserted into the inside of the voltage stabilizer from the penetrating part of the bottom head of the voltage stabilizer, and passes through the sleeve of the electric heating element. outer diameter It runs through the bottom head of the voltage stabilizer, and ...

AI Technical Summary

Problems solved by technology

This one-time self-fluxing welding process is relatively simple, but requires a large penetration depth. In order to ensure full penetration of the weld root, the welding process requires a large heat input, and the heat dissipation conditions of the connecting parts are poor, and thermal cracks are prone to occur.

In order to reduce the tendency of weld thermal cracking, the ferritic stainless steel filling ring is used as the filling material. This material is different from the base material, the impact toughness is lower than the base material, and the industrial consumption is small, so it needs to be smelted separately. The actual use mainly depends on imports. expensive

In addition, this structure has very high requirements for the centering of the weld bevel or welding arc, and a little carelessness may cause welding defects such as incomplete penetration or poor fusion on one side, and the formation of the root of the weld and the surface of the weld is not easy Taking into account, to a certain extent, affects the quality of the weld

Since the weld is a primary circuit pressure boundary weld, if the weld has welding defects such as unilateral infusion, incomplete penetration, or thermal cracks, it needs to be replaced again, causing huge losses

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